Why is total mechanical power always constant ?

Why is total mechanical power always constant ?
by

1 Answer

Answer :

When a falling object starts to come down , the potential decreases as the height decreases. During this time, however, the kinetic energy of the object gradually increases. In fact , the potential energy is converted into kinetic energy and the more the potential energy decreases , the more the kinetic energy increases. For this reason, the sum of potential energy and kinetic energy, that is, the total mechanical energy, is always constant.
by

Related questions

A 40 kW engine has a mechanical efficiency of 80 %. If the frictional power is assumed to be constant with load, what is the approximate value of the mechanical efficiency at 50 % of the rated load? (a) 45% (b) 55 % (c) 65% (d) 75%

Description : A 40 kW engine has a mechanical efficiency of 80 %. If the frictional power is assumed to be constant with load, what is the approximate value of the mechanical efficiency at 50 % of the rated load? (a) 45% (b) 55 % (c) 65% (d) 75%

Last Answer : Ans :c

Total mechanical losses ( frictional losses , pumping loss in intake and exhaust and power accessories) will amount to a.10-20 % ihp b.2-10 % ihp c.20-30 % ihp d.30 -50 % ihp

Description : Total mechanical losses ( frictional losses , pumping loss in intake and exhaust and power accessories) will amount to a.10-20 % ihp b.2-10 % ihp c.20-30 % ihp d.30 -50 % ihp

Last Answer : a.10-20 % ihp

The statement that the sum of the kinetic and potential energies of a particle in the earth's gravitational field is constant is known as a.Principle of conservation of mechanical energy b.Law of gravitation c.Newton's law d.Principle of conservation of momentum e.Law of nature

Description : The statement that the sum of the kinetic and potential energies of a particle in the earth's gravitational field is constant is known as a.Principle of conservation of mechanical energy b.Law of gravitation c.Newton's law d.Principle of conservation of momentum e.Law of nature

Last Answer : a. Principle of conservation of mechanical energy

What is the dependence of mechanical force per unit area of charged conductor on the surface charge density and the dielectric constant of the medium

Description : What is the dependence of mechanical force per unit area of charged conductor on the surface charge density and the dielectric constant of the medium

Last Answer : What is the dependence of mechanical force per unit area of charged conductor on the surface charge density and the dielectric constant of the medium

Rittinger number which designates the new surface produced per unit of mechanical energy absorbed by the material being crushed, depends on the (A) State or manner of application of the crushing force (B) Ultimate strength of the material (C) Elastic constant of the material (D) All (A), (B) and (C)

Description : Rittinger number which designates the new surface produced per unit of mechanical energy absorbed by the material being crushed, depends on the (A) State or manner of application of the crushing force (B) Ultimate strength of the material (C) Elastic constant of the material (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

Pick out the wrong statement. (A) Mechanical agitation is required, if the system has low interfacial tension (B) Sieve tray towers are generally used for systems having low interfacial tension (C) When Henry's law constant is very small, then the mass transfer rate is controlled by the gas film resistance (D) Taylor-Prandtl analogy for heat and mass transfer considers the transfer through both laminar and turbulent layers

Description : Pick out the wrong statement. (A) Mechanical agitation is required, if the system has low interfacial tension (B) Sieve tray towers are generally used for systems having low ... Prandtl analogy for heat and mass transfer considers the transfer through both laminar and turbulent layers

Last Answer : (A) Mechanical agitation is required, if the system has low interfacial tension

Due to constant use both inlet and exhaust valves and their seats subjected to a) stress wear b) strain wear c) mechanical wear d) tensile wear

Description : Due to constant use both inlet and exhaust valves and their seats subjected to a) stress wear b) strain wear c) mechanical wear d) tensile wear

Last Answer : c) mechanical wear

The efficiency of the plant _____ with the mechanical draught a) Increases b) Decreases c) Remain constant d) None of the above

Description : The efficiency of the plant _____ with the mechanical draught a) Increases b) Decreases c) Remain constant d) None of the above

Last Answer : a) Increases

Isochoric process is one in which  (a) free expansion takes place  (b) very little mechanical work is done by the system  (c) no mechanical work is done by the system  (d) all parameters remain constant

Description : Isochoric process is one in which  (a) free expansion takes place  (b) very little mechanical work is done by the system  (c) no mechanical work is done by the system  (d) all parameters remain constant

Last Answer : Answer : c

What two things does mechanical waves always need to travel through?

Description : What two things does mechanical waves always need to travel through?

Last Answer : What is the answer ?

Pick out the correct statement. (A) If an insoluble gas is passed through a volatile liquid placed in a perfectly insulated container, the temperature of the liquid will increase (B) A process is irreversible as long as Δ S for the system is greater than zero (C) The mechanical work done by a system is always equal to∫P.dV (D) The heat of formation of a compound is defined as the heat of reaction leading to the formation of the compound from its reactants

Description : Pick out the correct statement. (A) If an insoluble gas is passed through a volatile liquid placed in a perfectly insulated container, the temperature of the liquid will increase (B) A ... compound is defined as the heat of reaction leading to the formation of the compound from its reactants

Last Answer : (D) The heat of formation of a compound is defined as the heat of reaction leading to the formation of the compound from its reactants

The law of conservation of mechanical energy is valid a.Irrespective of the nature of force field b.Only in gravitational field c.Only if the total work done by the particle in moving around in a closed trajectory is zero d.Only if the force is tangential to the trajectory e.None of the above

Description : The law of conservation of mechanical energy is valid a.Irrespective of the nature of force field b.Only in gravitational field c.Only if the total work done by the particle in moving around in a closed trajectory is zero d.Only if the force is tangential to the trajectory e.None of the above

Last Answer : c. Only if the total work done by the particle in moving around in a closed trajectory is zero

(2) Exclusion Principle of Pauli Explanation: The Pauli exclusion principle is the quantum mechanical principle that no two identical fermions (particles with half-integer spin) may occupy the same quantum state simultaneously. A more rigorous statement is that the total wave function for two identical fermions is anti-symmetric with respect to exchange of the particles.

Description : (2) Exclusion Principle of Pauli Explanation: The Pauli exclusion principle is the quantum mechanical principle that no two identical fermions (particles with half-integer spin) may occupy the same ... function for two identical fermions is anti-symmetric with respect to exchange of the particles.

Last Answer : The three elements most needed in common fertilizers are – (1) Sulphur, Phosphorous and Sodium (2) Nitrogen, Phosphorous and Sodium (3) Phosphorous, Sodium and Nitrogen (4) Calcium, Phosphorous and Potassium

In case of a centrifugal pump, the ratio of total delivered pressure to pressure developed with the impeller is called the __________ efficiency. (A) Manometric (B) Mechanical (C) Volumetric (D) Overall

Description : In case of a centrifugal pump, the ratio of total delivered pressure to pressure developed with the impeller is called the __________ efficiency. (A) Manometric (B) Mechanical (C) Volumetric (D) Overall

Last Answer : (A) Manometric