What is friction? Define coefficient of static friction and coefficient of kinetic friction.

What is friction? Define coefficient of static friction and coefficient of kinetic friction.
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What is friction? Define coefficient of static friction and coefficient of kinetic friction. Give the necessary formula for each.
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A block of mass m is pulled along a surface as shown. The coefficient of kinetic friction between the block and the surface is m and the tension in the rope is T. The acceleration of the block is (a) a = T cos q/mg (b) a = T cos q/mgm (c) a = T cos q/m + mmg (d) None of the above

Description : A block of mass m is pulled along a surface as shown. The coefficient of kinetic friction between the block and the surface is m and the tension in the rope is T. The acceleration of the block is (a) a = T cos q/mg (b) a = T cos q/mgm (c) a = T cos q/m + mmg (d) None of the above

Last Answer : Ans:(d)

Tangent of angle of friction is equal to (A) Kinetic friction (B) Limiting friction (C) Angle of repose (D) Coefficient of friction

Description : Tangent of angle of friction is equal to (A) Kinetic friction (B) Limiting friction (C) Angle of repose (D) Coefficient of friction

Last Answer : (D) Coefficient of friction

Ice skating is possible and practical because of a unique property of water. Is it because: w) The coefficient of kinetic friction of steel on frozen water decreases with decreasing temperature x) Ice readily sublimes y) The melting point decreases with increasing pressure z) Ice is a good thermal insulator

Description : Ice skating is possible and practical because of a unique property of water. Is it because: w) The coefficient of kinetic friction of steel on frozen water decreases with decreasing temperature x ... sublimes y) The melting point decreases with increasing pressure z) Ice is a good thermal insulator 

Last Answer : ANSWER: Y -- THE MELTING POINT DECREASES WITH INCREASING PRESSURE 

What is kinetic friction and static friction?

Description : What is kinetic friction and static friction?

Last Answer : Friction is the resistance to movement of an object pressing/resting/moving on a surface. It's not intuitively obvious but the standing still friction and moving friction are different. Assume you have a ... than the force required to keep it moving (kinetic friction) after it has begun to move.

Friction can be reduced by changing over from _____. A. Sliding to rolling B. Dynamic to static C. Potential energy to kinetic energy D. Rolling to sliding

Description : Friction can be reduced by changing over from _____. A. Sliding to rolling B. Dynamic to static C. Potential energy to kinetic energy D. Rolling to sliding

Last Answer : ANSWER: A

The function of ball bearings in a wheel is – (1) to increase friction (2) to convert kinetic friction into rolling friction (3) to convert static friction into kinetic friction (4) just for convenience

Description : The function of ball bearings in a wheel is – (1) to increase friction (2) to convert kinetic friction into rolling friction (3) to convert static friction into kinetic friction (4) just for convenience

Last Answer : (2) to convert kinetic friction into rolling friction Explanation: A ball bearing is a type of rollingelement bearing that uses balls to maintain the separation between the bearing races. The purpose of a ball bearing is to reduce rotational friction and support radial and axial loads.

Kinetic friction is always A. lesser than static friction B. greater than static friction C. equal to static friction D. equal to contact force

Description : Kinetic friction is always A. lesser than static friction B. greater than static friction C. equal to static friction D. equal to contact force

Last Answer : lesser than static friction

The function of ball bearings in a wheel is : (1) to increase friction (2) to convert kinetic friction into rolling friction (3) to convert static friction into kinetic friction (4) just for convenience

Description : The function of ball bearings in a wheel is : (1) to increase friction (2) to convert kinetic friction into rolling friction (3) to convert static friction into kinetic friction (4) just for convenience

Last Answer : to convert kinetic friction into rolling friction

A uniform cylinder of weight W is rolling while slipping on a rough horizontal surface under the influence of a horizontal force. The force of friction between the cylinder and the surface is a.Proportional to the coefficient of static friction b.Proportional to the coefficient of dynamic friction c.Indeterminate d.Determinate but depends on the acceleration of the cylinder e.None of the above

Description : A uniform cylinder of weight W is rolling while slipping on a rough horizontal surface under the influence of a horizontal force. The force of friction between the cylinder and the surface is a. ... c.Indeterminate d.Determinate but depends on the acceleration of the cylinder e.None of the above

Last Answer : c. Indeterminate

A 5 m ladder of mass 25 kg is placed in a position where its inclination to a vertical wall is at 30?. A 100 kg man is to climb the ladder. If the coefficient of static friction is 0.25 the height along ladder at which the slipping will be induced would be a.2.4 m b.1.6 m c.0.8 m d.1.2 m e.0.5 m

Description : A 5 m ladder of mass 25 kg is placed in a position where its inclination to a vertical wall is at 30?. A 100 kg man is to climb the ladder. If the coefficient of static friction is 0.25 the height along ladder at which the slipping will be induced would be a.2.4 m b.1.6 m c.0.8 m d.1.2 m e.0.5 m

Last Answer : c. 0.8 m

A uniform cylinder of weight W is rolling while slipping on a rough horizontal surface under the influence of a horizontal force. The force of friction between the cylinder and the surface is a.Indeterminate b.Proportional to the coefficient of dynamic friction c.Determinate but depends on the acceleration of the cylinder d.107 dynes e.Proportional to the coefficient of static friction

Description : A uniform cylinder of weight W is rolling while slipping on a rough horizontal surface under the influence of a horizontal force. The force of friction between the cylinder and the surface is a. ... on the acceleration of the cylinder d.107 dynes e.Proportional to the coefficient of static friction

Last Answer : c. Determinate but depends on the acceleration of the cylinder

The coefficient of static friction will have the highest value in case of a.Mild steel and mild steel b.Mild steel and copper c.Cast iron and steel d.Rope and wood e.Any of the above loctions

Description : The coefficient of static friction will have the highest value in case of a.Mild steel and mild steel b.Mild steel and copper c.Cast iron and steel d.Rope and wood e.Any of the above loctions

Last Answer : d. Rope and wood

A block of mass 37 kg rests on a rough horizontal plane having coefficient of static friction 0.3.

Description : A block of mass 37 kg rests on a rough horizontal plane having coefficient of static friction 0.3.

Last Answer : A block of mass 37 kg rests on a rough horizontal plane having coefficient of static friction ... force required to just move the block horizontally.

Calculate the coefficient of static friction for an object of mass 50 kg placed on horizontal table

Description : Calculate the coefficient of static friction for an object of mass 50 kg placed on horizontal table

Last Answer : Calculate the coefficient of static friction for an object of mass 50 kg placed on horizontal ... object just moves when spring balance shows 50N.

In the impact problems the following conditions must always be satisfied a.The total kinetic energy remains unchanged b.The total linear momentum remains unchanged c.The magnitude of the total linear momentum is multiplied by the coefficient of restitution d.The kinetic energy of the system is reduced by a factor proportional to the coefficient of restitution e.None of the above

Description : In the impact problems the following conditions must always be satisfied a.The total kinetic energy remains unchanged b.The total linear momentum remains unchanged c.The magnitude of the total linear ... is reduced by a factor proportional to the coefficient of restitution e.None of the above

Last Answer : b. The total linear momentum remains unchanged

The coefficient of fluctuation of energy of flywheel is 1. ratio of maximum fluctuation of energy to work done per cycle 2. ratio of to work done per cycle to maximum fluctuation of energy 3. difference between maximum and minimum kinetic energy during the cycle 4. ratio of maximum and minimum kinetic energy during the cycle

Description : The coefficient of fluctuation of energy of flywheel is 1. ratio of maximum fluctuation of energy to work done per cycle 2. ratio of to work done per cycle to maximum fluctuation of energy ... minimum kinetic energy during the cycle 4. ratio of maximum and minimum kinetic energy during the cycle

Last Answer : 1. ratio of maximum fluctuation of energy to work done per cycle

The coefficient of fluctuation of energy of flywheel is, (A) Ratio of maximum fluctuation of energy to work done per cycle (B) Ratio of to work done per cycle to maximum fluctuation of energy (C) Difference between maximum and minimum kinetic energy during the cycle (D) Ratio of maximum and minimum kinetic energy during the cycle

Description : The coefficient of fluctuation of energy of flywheel is, (A) Ratio of maximum fluctuation of energy to work done per cycle (B) Ratio of to work done per cycle to maximum fluctuation of ... minimum kinetic energy during the cycle (D) Ratio of maximum and minimum kinetic energy during the cycle

Last Answer : (A) Ratio of maximum fluctuation of energy to work done per cycle

Kinetic friction is a.Maximum value of frictional force when a body is about to move b.Friction between two well lubricated bodies c.Friction force acting when the body is in motion d.Driction force which keeps a body in motion e.None of the above

Description : Kinetic friction is a.Maximum value of frictional force when a body is about to move b.Friction between two well lubricated bodies c.Friction force acting when the body is in motion d.Driction force which keeps a body in motion e.None of the above

Last Answer : c. Friction force acting when the body is in motion

The maximum frictional force which comes into play when a body just begins to slide over the surface of another body is known as a.Kinetic friction b.Rolling friction c.Dynamic friction d.Limiting friction e.Sliding friction

Description : The maximum frictional force which comes into play when a body just begins to slide over the surface of another body is known as a.Kinetic friction b.Rolling friction c.Dynamic friction d.Limiting friction e.Sliding friction

Last Answer : d. Limiting friction

State the laws of kinetic friction.

Description : State the laws of kinetic friction.

Last Answer : State the laws of kinetic friction.

What would cause the force of kinetic friction to increase?

Description : What would cause the force of kinetic friction to increase?

Last Answer : an increase in uk (apex)

In case of a pipe exit fitted with a nozzle, the (A) Conversion of kinetic head to pressure head is facilitated (B) Conversion of pressure head to kinetic head is facilitated (C) Power transmitted through the nozzle is maximum, when the head lost due to friction in the pipe is equal to one third of the total supply head (D) Both (B) and (C)

Description : In case of a pipe exit fitted with a nozzle, the (A) Conversion of kinetic head to pressure head is facilitated (B) Conversion of pressure head to kinetic head is facilitated (C) Power transmitted through the nozzle ... in the pipe is equal to one third of the total supply head (D) Both (B) and (C)

Last Answer : (D) Both (B) and (C)

Kinetic friction is the (A) Tangent of angle between normal reaction and the resultant of normal reaction and the limiting friction (B) Ratio of limiting friction and normal reaction (C) The friction force acting when the body is just about to move (D) The friction force acting when the body is in motion

Description : Kinetic friction is the (A) Tangent of angle between normal reaction and the resultant of normal reaction and the limiting friction (B) Ratio of limiting friction and normal reaction (C) The friction force ... body is just about to move (D) The friction force acting when the body is in motion

Last Answer : (D) The friction force acting when the body is in motion

A block of wood initially at rest slides down an inclined plane. Neglecting friction, the kinetic energy of the block at the bottom of the plane is: w) all converted into heat x) equal to its potential energy (with respect to the bottom of the plane) when it was at the top of the plane y) less than its kinetic energy at the top of the plane z) dependant on the materials of which the block is made

Description : A block of wood initially at rest slides down an inclined plane. Neglecting friction, the kinetic energy of the block at the bottom of the plane is: w) all converted into heat x) equal to its ... kinetic energy at the top of the plane z) dependant on the materials of which the block is made 

Last Answer : ANSWER: X -- EQUAL TO ITS POTENTIAL ENERGY (WITH RESPECT TO THE BOTTOM OF PLANE) WHEN IT WAS AT THE TOP OF THE PLANE.

Kinetic friction is the?

Description : Kinetic friction is the?

Last Answer : Kinetic friction is the friction force acting when the body is in motion.

Volute of a centrifugal pump should be designed in a fashion, such that the (A) Kinetic head gets converted into static head (B) Moving stream gradually reduces velocity (C) Mean velocity remains constant (D) None of these

Description : Volute of a centrifugal pump should be designed in a fashion, such that the (A) Kinetic head gets converted into static head (B) Moving stream gradually reduces velocity (C) Mean velocity remains constant (D) None of these

Last Answer : (A) Kinetic head gets converted into static head

Design of the casing of centrifugal pump should be such as to minimise the (A) Back flow through impeller (B) Loss of kinetic head (C) Loss of static head (D) None of these

Description : Design of the casing of centrifugal pump should be such as to minimise the (A) Back flow through impeller (B) Loss of kinetic head (C) Loss of static head (D) None of these

Last Answer : (B) Loss of kinetic head

Good design of the casing of a centrifugal pump aims at minimising the (A) Cavitation (B) Frictional losses (C) Kinetic energy loss (D) Static head

Description : Good design of the casing of a centrifugal pump aims at minimising the (A) Cavitation (B) Frictional losses (C) Kinetic energy loss (D) Static head

Last Answer : Option C

Does anyone know the coefficient of friction for an A rated tire?

Description : Does anyone know the coefficient of friction for an A rated tire?

Last Answer : answer:I can't give you an exact number on that, but I the A traction grade is the second-highest rating given to a tire, AA being the highest. The traction grade applies to wet ... 'd see on a skidpad test. There, you have sidewall construction and vehicle characteristics to consider as well.

A particle inside a hollow sphere of internal radius r with coefficient of friction 1/?3 can rest upto height of a.0.18 r b.0.435 r c.0.25 r d.0.134 r e.0.125 r

Description : A particle inside a hollow sphere of internal radius r with coefficient of friction 1/?3 can rest upto height of a.0.18 r b.0.435 r c.0.25 r d.0.134 r e.0.125 r

Last Answer : d. 0.134 r

A car is travelling at 90 km/hour on a rough road where the coefficient of friction between the road and the tyre is 0.5. The distance the car will skid before stopping when the brakes are jammed suddenly would be a.127.4 m b.95.55 m c.63.7 m d.31.85 m e.90 m

Description : A car is travelling at 90 km/hour on a rough road where the coefficient of friction between the road and the tyre is 0.5. The distance the car will skid before stopping when the brakes are jammed suddenly would be a.127.4 m b.95.55 m c.63.7 m d.31.85 m e.90 m

Last Answer : c. 63.7 m

The ideal angle of banking provided on roads a.Depends on (velocity)2 of vehicle b.Depends on the nature of road surface c.Depend on coefficient of friction between the road and the vehicle cantact point d.Depends on weight of the vehicle e.All above

Description : The ideal angle of banking provided on roads a.Depends on (velocity)2 of vehicle b.Depends on the nature of road surface c.Depend on coefficient of friction between the road and the vehicle cantact point d.Depends on weight of the vehicle e.All above

Last Answer : a. Depends on (velocity)2 of vehicle

Which of the following bearing will have least coefficient of friction a.Single ball bearing b.Cylinderical roller bearing c.Self aligury bearing d.Thrust ball bearing e.Tapered bearing

Description : Which of the following bearing will have least coefficient of friction a.Single ball bearing b.Cylinderical roller bearing c.Self aligury bearing d.Thrust ball bearing e.Tapered bearing

Last Answer : e. Tapered bearing

The coefficient of friction is a.The tangent of the angle between the normal reaction and direction of limiting friction b.The tangent of the angle between the normal reaction and the resultant of the normal reaction and the limiting friction c.The tangent of the angle of the net resultant force with the direction of motion d.The tangent of the angle between the horizontal plane and the resultant force e.The angle between the normal reaction and the resultant of normal reaction and the limiting friction

Description : The coefficient of friction is a.The tangent of the angle between the normal reaction and direction of limiting friction b.The tangent of the angle between the normal reaction and the resultant ... e.The angle between the normal reaction and the resultant of normal reaction and the limiting friction

Last Answer : a. The tangent of the angle between the normal reaction and direction of limiting friction

A man wished to move a block of size 3 m x 3 m weighing 80 kg. The coefficient of friction between the block and the ground is 0.27. Which of the following methods should be used? a.Slide along the ground by pushing b.Ask for cranes c.Pull it d.Tip it over e.Lift it bodily

Description : A man wished to move a block of size 3 m x 3 m weighing 80 kg. The coefficient of friction between the block and the ground is 0.27. Which of the following methods should be used? a.Slide along the ground by pushing b.Ask for cranes c.Pull it d.Tip it over e.Lift it bodily

Last Answer : d. Tip it over

A crate weighing 40 kg rests on a cart moving with an acceleration W. The coefficient of friction between the cart and the crate is a.2.45 m/sec2 b.4.00 m/sec2 c.0.25 m/sec2 d.4.16 m/sec2 e.1.25 m/sec2

Description : A crate weighing 40 kg rests on a cart moving with an acceleration W. The coefficient of friction between the cart and the crate is a.2.45 m/sec2 b.4.00 m/sec2 c.0.25 m/sec2 d.4.16 m/sec2 e.1.25 m/sec2

Last Answer : a. 2.45 m/sec2

A weight of 4.9 N rests on a rough horizontal floor that has a coefficient of friction of 0.5. If g = 9.8 m/s2, the smallest horizontal force that gives the weight an acceleration of 4m/s2 is most nearly a.2.5 N b.3 N c.2 N d.4.5 N e.4.9 N

Description : A weight of 4.9 N rests on a rough horizontal floor that has a coefficient of friction of 0.5. If g = 9.8 m/s2, the smallest horizontal force that gives the weight an acceleration of 4m/s2 is most nearly a.2.5 N b.3 N c.2 N d.4.5 N e.4.9 N

Last Answer : d. 4.5 N

A 20kg toy wagon is pulled with an applied force of 35N. if the handle of the wagon is at 45, and the coefficient of friction is 0.1, find the acceleration of the wagon?

Description : A 20kg toy wagon is pulled with an applied force of 35N. if the handle of the wagon is at 45, and the coefficient of friction is 0.1, find the acceleration of the wagon?

Last Answer : 9.19 m/s^2

What is the coefficient of friction ?

Description : What is the coefficient of friction ?

Last Answer : When an object touches another object and moves over it, then the ratio of frictional force acting on that object to vertical reaction ball is called friction coefficient .

Name two factors on which the coefficient of friction depends.

Description : Name two factors on which the coefficient of friction depends.

Last Answer : Name two factors on which the coefficient of friction depends.

Assertion (A): Oil as a cutting fluid result in a lower coefficient of friction. Reason (R): Oil forms a thin liquid film between the tool face and chip, and it provides 'hydrodynamic lubrication'. [IES- 2000] (a) Both A and R are individually true and R is the correct explanation of A (b) Both A and R are individually true but R is not the correct explanation of A (c) A is true but R is false (d) A is false but R is true

Description : Assertion (A): Oil as a cutting fluid result in a lower coefficient of friction. Reason (R): Oil forms a thin liquid film between the tool face and chip, and it provides 'hydrodynamic lubrication'. [IES- 2000] (a ... explanation of A (c) A is true but R is false (d) A is false but R is true

Last Answer : (c) A is true but R is false

In an oil-lubricated journal bearing, coefficient of friction between the journal and the bearing. [IES-1995] (a) Remains constant at all speeds. (b) is minimum at zero speed and increases monotonically with increase in speed. (c) is maximum at zero speed and decreases monotonically with increase in speed. (d) becomes minimum at an optimum speed and then increases with further increase in speed.

Description : In an oil-lubricated journal bearing, coefficient of friction between the journal and the bearing. [IES-1995] (a) Remains constant at all speeds. (b) is minimum at zero speed and increases ... speed. (d) becomes minimum at an optimum speed and then increases with further increase in speed.

Last Answer : (d) becomes minimum at an optimum speed and then increases with further increase in speed.

Satisfactory hydrodynamic film in a journal bearing is formed when (a) Journal speed is low; unit pressure on the bearing is high and viscosity of lubricant used is low [IES-2006] (b) Journal speed is low; unit pressure on the bearing is low and viscosity of lubricant used is low (c) Journal speed is high; unit pressure on the bearing is high and viscosity of lubricant used is high (d) Appropriate combination of journal speed, unit pressure on bearing and lubricant viscosity exists resulting in low coefficient of friction

Description : Satisfactory hydrodynamic film in a journal bearing is formed when (a) Journal speed is low; unit pressure on the bearing is high and viscosity of lubricant used is low [IES-2006] ... journal speed, unit pressure on bearing and lubricant viscosity exists resulting in low coefficient of friction

Last Answer : (c) Journal speed is high; unit pressure on the bearing is high and viscosity of lubricant used is high

Consider tile following statements: [IES-1993; 2002; 2006] Radius of friction circle for a journal bearing depends upon 1. Coefficient of friction 2. Radius of the journal 3. Angular speed of rotation of the shaft Which of the statements given above are correct? (a) 1,2 and 3 (b) Only 1 and 2 (c) Only 2 and 3 (d) Only 1 and 3

Description : Consider tile following statements: [IES-1993; 2002; 2006] Radius of friction circle for a journal bearing depends upon 1. Coefficient of friction 2. Radius of the journal 3. Angular speed of rotation of the shaft Which of the ... ) 1,2 and 3 (b) Only 1 and 2 (c) Only 2 and 3 (d) Only 1 and 3

Last Answer : (b) Only 1 and 2

Increase in values of which of the following results in an increase of the coefficient of friction in a hydrodynamic bearing? [IES 2007] 1. Viscosity of the oil. 2. Clearance between shaft and bearing. 3. Shaft speed. Select the using the code given below: (a) 1 and 2 only (b) 1 and 3 only (c) 2 and 3 only (d) 1, 2 and 3

Description : Increase in values of which of the following results in an increase of the coefficient of friction in a hydrodynamic bearing? [IES 2007] 1. Viscosity of the oil. 2. Clearance between shaft and bearing. 3. Shaft speed. Select the ... 1 and 2 only (b) 1 and 3 only (c) 2 and 3 only (d) 1, 2 and 3

Last Answer : (b) 1 and 3 only

Which of the following are not true for petroff’s equation? a) Shaft is considered concentric with the bearing b) Bearing is subjected to light load c) Is used to find coefficient of friction d) Frictional torque is given by fpr2l

Description : Which of the following are not true for petroff’s equation? a) Shaft is considered concentric with the bearing b) Bearing is subjected to light load c) Is used to find coefficient of friction d) Frictional torque is given by fpr2l

Last Answer : d) Frictional torque is given by fpr2l

In trapezoidal threads, f (coefficient of friction) can be taken as a) f sec θ b) f cos θ c) f sin θ d) f cosec θ

Description : In trapezoidal threads, f (coefficient of friction) can be taken as a) f sec θ b) f cos θ c) f sin θ d) f cosec θ

Last Answer : a) f sec θ

Efficiency of the screw _______ with increase of coefficient of friction. a) decreases b) increases c) has no effect d) cannot be determined

Description : Efficiency of the screw _______ with increase of coefficient of friction. a) decreases b) increases c) has no effect d) cannot be determined

Last Answer : a) decreases

Self-locking takes place when a) Coefficient of friction is equal to or greater than the tangent of the helix angle b) Coefficient of friction is lesser than or equal to the tangent of the helix angle c) Coefficient of friction is equal to or greater than the tangent of the helix angle d) None of the mentioned

Description : Self-locking takes place when a) Coefficient of friction is equal to or greater than the tangent of the helix angle b) Coefficient of friction is lesser than or equal to the tangent of the helix ... friction is equal to or greater than the tangent of the helix angle d) None of the mentioned

Last Answer : c) Coefficient of friction is equal to or greater than the tangent of the helix angle