Physics Work, Power, Energy and Collision Conceptual Questions with answers for JEE Mains and other engineering Entrance Exam.

## Work Power Energy

Question 1 |

A body of mass 10

*kg*is dropped to the ground from a height of 10*metres*. The work done by the gravitational force is (g = 9.8 m/sec^{2})**Related:** Amrita Vishwa Vidyapeetham Exam Chemistry Questions

– 980 Joules | |

+ 980 Joules | |

+ 490 Joules | |

– 490 Joules |

Question 2 |

A ball is released from certain height. It loses 50% of its kinetic energy on striking the ground. It will attain a height again equal to

Three fourth initial height | |

Half the initial height | |

None of these | |

One fourth the initial height |

Question 3 |

Masses of two substances are 1

*g*and 9*g*respectively. If their kinetic energies are same, then the ratio of their momentum will be3 : 1 | |

1 : 9 | |

9 : 1 | |

1 : 3 |

Question 4 |

Two bodies having same mass 40

*kg*are moving in opposite directions, one with a velocity of 10m/s and the other with 7 m/s. If they collide and move as one body, the velocity of the combination is1.5 m/s | |

10 m/s | |

3 m/s | |

7 m/s |

Question 5 |

It is easier to draw up a wooden block along an inclined plane than to haul it vertically, principally because

The friction is reduced | |

The mass becomes smaller | |

Only a part of the weight has to be overcome | |

‘g’ becomes smaller |

Question 6 |

If the water falls from a dam into a turbine wheel 19.6

*m*below, then the velocity of water at the turbine is (g = 9.8 m/s^{2})9.8 m/s | |

19.6 m/s | |

39.2 m/s | |

98.0 m/s |

Question 7 |

A ball is dropped from height 10

*m*. Ball is embedded in sand 1*m*and stops, thenOnly momentum remains conserved | |

Only kinetic energy remains conserved | |

Neither K.E. nor momentum is conserved | |

Both momentum and K.E. are conserved |

Question 8 |

A rubber ball is dropped from a height of 5

*m*on a planet where the acceleration due to gravity is not known. On bouncing, it rises to 1.8*m*. The ball loses its velocity on bouncing by a factor of9/25 | |

16/25 | |

2/5 | |

3/5 |

Question 9 |

Work done in raising a box depends on

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How fast it is raised | |

None of these | |

The strength of the man | |

The height by which it is raised |

Question 10 |

A body of mass 2

*kg*is thrown up vertically with K.E. of 490 joules. If the acceleration due to gravity is 9.8m/s^{2}, then the height at which the K.E. of the body becomes half its original value is given by50 m | |

10 m | |

25 m | |

12.5 m |

Question 11 |

A cylinder of mass 10

*kg*is sliding on a plane with an initial velocity of 10*m*/*s*. If coefficient of friction between surface and cylinder is 0.5, then before stopping it will describe7.5 m | |

5 m | |

12.5 m | |

10 m |

Question 12 |

Two perfectly elastic particles

*P*and*Q*of equal mass travelling along the line joining them with velocities 15*m*/*sec*and 10*m*/*sec*. After collision, their velocities respectively (in*m*/*sec*) will be0, 25 | |

5, 20 | |

10, 15 | |

20, 5 |

Question 13 |

The quantity that is not conserved in an inelastic collision is

Momentum | |

Total energy | |

Kinetic energy | |

All of these |

Question 14 |

A body of mass 4

*kg*moving with velocity 12*m/s*collides with another body of mass 6*kg*at rest. If two bodies stick together after collision, then the loss of kinetic energy of system is144 J | |

172.8 J | |

Zero | |

288 J |

Question 15 |

A mass of 10

*gm*moving with a velocity of 100*cm*/*s*strikes a pendulum bob of mass 10*gm*. The two masses stick together. The maximum height reached by the system now is (g = 10 m/s^{2})Zero | |

1.25 cm | |

5 cm | |

2.5 cm |

Question 16 |

A 10

*H*.*P*. motor pumps out water from a well of depth 20*m*and fills a water tank of volume 22380*litres*at a height of 10*m*from the ground. the running time of the motor to fill the empty water tank is (g = 10 ms^{–2})15 minutes | |

20 minutes | |

10 minutes | |

5 minutes |

Question 17 |

A motor boat is travelling with a speed of 3.0

*m*/*sec*. If the force on it due to water flow is 500*N*, the power of the boat is150 kW | |

1.5 kW | |

15 kW | |

150 W |

Question 18 |

An inelastic ball is dropped from a height of 100

*m*. Due to earth, 20% of its energy is lost. To what height the ball will rise**Related:** Redox Reaction Examples with answers

20 m | |

60 m | |

80 m | |

40 m |

Question 19 |

The kinetic energy of a body of mass 3

*kg*and momentum 2*Ns*is3/2 J | |

4 J | |

2/3 J | |

1 J |

Question 20 |

A position dependent force F = 7 – 2x + 3x

^{2}newton acts on a small body of mass 2*kg*and displaces it from x = 0 to x = 5 m. The work done in*joules*is70 | |

135 | |

270 | |

35 |

Question 21 |

A steel ball of radius 2

*cm*is at rest on a friction-less surface. Another ball of radius 4*cm*moving at a velocity of 81*cm*/*sec*collides elastically with first ball. After collision the smaller ball moves with speed of63 cm/sec | |

None of these | |

144 cm/sec | |

81 cm/sec |

Question 22 |

If the stone is thrown up vertically and return to ground, its potential energy is maximum

During the return journey | |

At the bottom | |

At the maximum height | |

During the upward journey |

Question 23 |

A mass of 0.5

*kg*moving with a speed of 1.5*m/s*on a horizontal smooth surface, collides with a nearly weightless spring of force constant k = 50 N/m. The maximum compression of the spring would be0.15 m | |

0.12 m | |

1.5 m | |

0.5 m |

There are 23 questions to complete.

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