Recent questions tagged physics 9th

Description : two army person a and b each of weight -Physics 9th

Last Answer : The ratio of powers of A and B = 2: 1 Explanation : Where , Fa = 500N S = 10m Fb = 500N ta = 20s , tb = 40s

Description : two persons a and b each of weight 500 n climb up a rope through a height of 10 m . a takes 20 s while b takes 40 s to achieve this task . what is the ratio of powers of a and b ? -Physics 9th

Last Answer : The ratio of powers of A and B = 2: 1 Explanation : Where , Fa = 500N S = 10m Fb = 500N ta = 20s , tb = 40s

Description : Two army persons A and B each of weight of 500 N climb up a rope through a height of 10 m. A takes 20 s while B takes 40 s to achieve this task. -Physics 9th

Last Answer : The ratio of powers of A and B = 2: 1 Explanation : Where , Fa = 500N S = 10m Fb = 500N ta = 20s , tb = 40s

Description : Two army persons A and B each of weight of 500 N climb up a rope through a height of 10 m. -Physics 9th

Last Answer : Here you go :

Description : can average speed of a moving object be zero -Physics 9th

Last Answer : Answer : No Explaination Speed is the distance travelled in the given time. Distance can never be zero. Therefore, average speed will always be a positive value and will not be zero. Speed is a scalar quantity and has only magnitude.

Description : Obtain a relation for the distance travelled by an object moving with a uniform acceleration in the interval between 4th and 5th seconds -Physics 9th

Last Answer : Uniform acceleration in the interval between 4th and 5th seconds = = (5u + 1/2 * a * 5^2) - (4u + 1/2 * a * 4^2) = 5u + 1/2 *a * 25 - 4u + 1/2 * a * 16 = u + 1/2 * a * (25-16) = u + 1/2 * a * 9 = u + 9/2 * a If it starts from rest then the displacement will be 9/2a. hope this helps!

Description : ncert exemplar class 9th science pdf -Physics 9th

Last Answer : matter in our surroindings Which one of the following sets of phenomena would increase on raising the temperature? (a) Diffusion, evaporation, compression of gases (b) Evaporation, compression of gases, solubility ... Pressure (i) cubic metre (b) Temperature (ii) kilogram (c) Density (iii) pascal

Description : Can non uniform linear motion be accelerated ? -Physics 9th

Last Answer : Yes, the statement is correct. In a uniform linear motion, there is no change in the magnitude or direction i.e., velocity is constant, hence there will be no acceleration. Further, in a ... motion, the direction of motion changes at each point.. Hence, the uniform circular motion is accelerated.

Description : Best Mind Map or Flow Chart of sound Ch -14 class 9th Physics -Physics 9th

Last Answer : NEED ANSWER

Description : Best Mind Map or Flow Chart of work, energy and power Ch -13 class 9th Physics -Physics 9th

Last Answer : NEED ANSWER

Description : Give reason how will the force of attraction between two bodies changes if -Physics 9th

Last Answer : Therefore when the distance between the objects is reduced to half, then the force of gravitation increases by four times the original force.

Description : Find the energy possessed by an object of mass 10 kg when it is at a height of 2 m above the ground. Given, g = 10 m/s2 -Physics 9th

Last Answer : Given, Mass of object m=10kg. Height h=6m. Acceleration due to gravity g=9.8m/s2 Potential Energy of object P.E=m×g×h ⇒mgh=10×9.8×6=98×6 =588J Energy possessed by the object is 588Joule.

Description : An electric bulb of 100 W is used for 8 h per day. Calculate the 'units' of energy consumed in one day by the bulb? -Physics 9th

Last Answer : Given : t=6 hrs P=0.06 kW Thus energy consumed per day is: E=Pt=0.06×6=0.36 kWh=0.36 units

Description : A force of 10 N displaces a body by a distance of 3 m at an angle 60° to its own direction. Find the amount of work done. -Physics 9th

Last Answer : F=10N,S=2m,θ=600 So, Work=F×Scosθ=10×2cos600 =10×2×21​=10J

Description : An engineer is asked to design a playground slide such that the speed a child reaches at the bottom does not exceed 4.0 m/s. Determine the maximum height that the slide can be.?Given, g = 9.8 m/s2. -Physics 9th

Last Answer : Entire PE is converted to KE when the child reaches bottom So KE = PE 12mv2=mgH12mv2=mgH or H=v22g=162×9.8=.816mH=v22g=162×9.8=.816m

Description : A rocket is moving up with a velocity v. If the velocity of this rocket is suddenly tripled, what will be the ratio of two kinetic energies? -Physics 9th

Last Answer : hope its clear

Description : When the force acts at right angle to the direction of motion, what is the work done by the force -Physics 9th

Last Answer : Let F is the force applied and s is the displacement produce and the angle between force and displacement is θ The work done by this force is given as FW = Fs Cosθ Its unit is joule

Description : If the mass of the body is doubled and velocity is made halved, the kinetic energy will become? -Physics 9th

Last Answer : New kinetic energy becomes, So, the new kinetic energy of the object gets doubled.

Description : An object of mass m and velocity v has kinetic energy= 200J. Find the new kinetic energy if the mass of the object becomes double and velocity still remains the same? -Physics 9th

Last Answer : let the k.e. in first case be x x = 1/2*m*v^2=200j in second case let the kinetic energy be x' v'=v m'=2m x'= 1/2*2m*v^2 x'= 2(1/2*m*v^2) x'=2(x) x'=2*200j x'=400j

Description : Calculate the power of an electric motor that can lift 800 kg of water to store in a tank at a height of 1500cm in 20s -Physics 9th

Last Answer : The power of an electric motor to store the water is 6000 W. Given m= 800 kg, h = 1500 cm = 15 m, g = 10 m/s^2 and t = 20 s. W = 120000 J. P = 6000 W. Thus, the power of an electric motor to store the water is 6000 W.Apr 6, 2016

Description : An electric heater of 1000 W is used for two hours in a day? What is the cost of using it for a month of 28 days, if one unit costs 3.00 rupees? -Physics 9th

Last Answer : energy consumed by heater of 1000W for 2h in one day=1000/1000×2 =2units number of units=W×h×day/1000 energy consumed by heater in 28 day 2×28=56units cost of 1unit =RS 3 cost of 56unit=3×56=RS 168

Description : An object with 100 N weights is raised to a height of 15m. Find the potential energy possessed by the object at that height. Also find the new potential energy: -Physics 9th

Last Answer : Potential Energy is given by PE=mgHPE=mgH Given mg=100N and H=15 m PE=100 15=1500JPE=100 15=1500J If If the same object is raised half of its original height i.e H= 7.5 m PE=100 7.5=750JPE=100 ... same object is raised to three times of its original height i.e H=45 m PE=100 45=4500JPE=100 45=4500J

Description : How is work and energy related to each other? -Physics 9th

Last Answer : Work results when a force acts upon an object to cause a displacement. The Energy is capacity for doing work. It may exist in potential, kinetic, thermal, electrical, chemical, nuclear, or other various forms. ... shares the same units of measure as work. The SI unit of work or energy is the joule.

Description : If energy is neither created nor destroyed then from where do we get energy? -Physics 9th

Last Answer : The first law of thermodynamics, also known as Law of Conservation of Energy, states that energy can neither be created nor destroyed; energy can only be transferred or changed from one form to another. ... on a light would seem to produce energy; however, it is electrical energy that is converted.

Description : State and explain one example where kinetic energy is present in a body and is used -Physics 9th

Last Answer : (i) Kinetic energy is the energy present in a body by virtue of its motion. When water is stored in a dam at particular height, we say it has maximum potential energy as the water ... potential energy is stored in the water which transforms into kinetic energy when it released from that height.

Description : Explain the Law of conservation of energy with pendulum. -Physics 9th

Last Answer : Law of conservation of energy state that energy can neither be created nor be destroyed it can only be converted into one form to another form. Now, let us consider a pendulum in which to ... pendulum to overcome the friction is gained by surrounding, So total energy of system will remain conserved.

Description : Derive the formula for potential energy. -Physics 9th

Last Answer : Potential energy is the energy possessed by the body by virtue of its position or configuration. Consider a body of mass m at a height 'h' from the ground. The amount of work done to raise this body to this height h against the force of gravity: W=F×h where F is the force of gravity . W=mgh

Description : Certain force acting on a 20 Kg mass changes its velocity from 5 m/s to 2 m/s. Calculate the work done by the force ? -Physics 9th

Last Answer : Certain force acting on 20 kg mass changes its velocity from 5 m s-1 to 2 m s-1. Calculate the work done by the force. (E k)2 = (1 )/2x 20 — (2)2 = 40 J.

Description : A car is accelerated on a levelled road and attains a velocity 4 times of its initial velocity. In this process the kinetic energy of the car -Physics 9th

Last Answer : The kinetic energy becomes 16 time that of initial kinetic energy Final speed = 4 times of initial speed The kinetic energy of car Where, m = mass of car v = initial velocity of car ... of initial velocity, then kinetic energy Hence, The kinetic energy becomes 16 time that of initial kinetic energy