Two bodies with kinetic energies in the ratio of 4 : 1 are moving with equal linear momentum. The ratio of their masses is
1) 1 : 2 2) 1 : 1 3) 4 : 1 4) 1 : 4 Answer: 4) 1 : 4... View Article
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If the K.E. of a particle is doubled, then its momentum will
1) Remain unchanged 2) Be doubled 3) Be quadrupled 4) Increase √2 times Answer: 4) Increase √2 times Solution: p = √2mE ... View Article
If the K.E of a body is increased by 300%, its momentum will increase by
1) 100% 2) 1560% 3) √300 % 4) 175% Answer: 1) 100% Solution: Initial K.E = 100% Final K.E = (300 +... View Article
Two masses of 1g and 4g are moving with equal kinetic energies. The ratio of the magnitudes of their linear momenta is
1) 4 : 1 2) √2 : 1 3) 1 : 2 4) 1 : 16 Answer: 3) 1 : 2 Solution:... View Article
According to work-energy theorem, the work done by the net force on a particle is equal to the change in its
1) Kinetic energy 2) Potential energy 3) Linear momentum 4) Angular momentum 5) Acceleration Answer: 1) Kinetic energy Solution: According... View Article
A light and a heavy body have equal momenta. Which one has greater K.E
1) The light body 2) The heavy body 3) The K.E are equal 4) Data is incomplete Answer: 1) The light... View Article
If a force F is applied on a body and it moves with a velocity v, the power will be
1) F × v 2) F/ v 3) F / v2 4) F × v2 Answer: 1) F × v Solution:... View Article
If we throw a body upwards with a velocity of 4 m/s, at what height does its kinetic energy reduce to half of the initial value (Taking g = 10 ms–1)
1) 4m 2) 2 m 3) 1 m 4) 0.4 m Answer: 4) 0.4 m Solution: Initial Kinetic Energy, K= (1/2)... View Article
If the force and displacement of a particle in direction of force are doubled. Work would be
1) Double 2) 4 times 3) Half 4) 1/4 times Answer: 2) 4 times Solution: Work = Force × Displacement If... View Article
A 50kg man with a 20 kg load on his head climbs up 20 steps of 0.25 m height each. The work done in climbing is
1) 5 J 2) 350 J 3) 100 J 4) 3430 J Answer: 4) 3430 J Solution: Work done to climb... View Article
The slope of the kinetic energy versus position vector curve gives the rate of change of
1) Momentum 2) velocity 3) Force 4) Power Answer: 1) Momentum Solution: Slope = dK.E/dx \(\begin{array}{l}\frac{dK.E}{dx}=\frac{d(1/2)mv^{2}}{dx}= \frac{1}{2}m2v.\frac{dv}{dx}\end{array} \) = mv (dv/dx) ... View Article
The work done against gravity in taking 10 kg mass at 1m height in 1 sec will be
1) 49 J 2) 98 J 3) 196 J 4) None of these Answer: 2) 98 J Solution: Work done =... View Article
A force of 5N acts on a 15kg body initially at rest. The work done by the force during the first second of motion of the body is
1) 5J 2) (⅚) J 3) 6J 4) 75J Answer: 2) (⅚) J Solution: Force, F = ma 5 = 15a... View Article
A man pushes a wall and fails to displace it. He does
1) Negative work 2) Positive but not maximum work 3) No work at all 4) Maximum work Answer: 3) No work... View Article
If the unit of force and length each be increased by four times, then the unit of energy is increased by
1) 16 times 2) 8 times 3) 2 times 4) 4 times Answer: 1) 16 times Work = Force x... View Article
A body of mass 1 kg is thrown upwards with a velocity 20 m/s. It momentarily comes to rest after attaining a height of 18 m. How much energy is lost due to air friction (g = 10 m / s2)
1) 20 J 2) 30 J 3) 40 J 4) 10 J Answer: 1) 20 J Solution: The energy lost due... View Article
Assertion The apparent weight of a body in an elevator moving with some downward acceleration is less then the actual weight of body. Reason The part of the weight is spent in producing downward acceleration, when body is in elevator.
1) If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion. 2) If... View Article
Assertion A reference frame attached to earth is an inertial frame of reference. Reason The reference frame which has zero acceleration is called a non-inertial frame of reference.
1) If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion. 2) If... View Article
Assertion The slope of momentum versus time curve gives us the acceleration. Reason Acceleration is given by the rate of change of momentum.
1) If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion. 2) If... View Article
A closed compartment containing gas is moving with some acceleration in the horizontal direction. Neglect effect of gravity. Then the pressure in the compartment is
1) Same everywhere 2) Lower in front side 3) Lower in the rear side 4) Lower in the upper side... View Article
