A body of mass 2 kg makes an elastic collision with another body at rest and continues to move in the original direction with one-fourth its original speed. The mass of the second body which collides with the first body is
2 kg
1.2 kg
3 kg
1.5 kg
In the stable equilibrium position, a body has
maximum potential energy
minimum potential energy
minimum kinetic energy
neither maximum nor minimum potential energy
A particle of mass m at rest is acted upon by a force P for a time t. Its kinetic energy after an interval t is
A car of mass 1000 kg accelerates uniformly from rest to a velocity of 54 km/h in 5 s. The average power of the engine during this period in watts is (neglect friction)
2000 W
22500 W
5000 W
2250 W
A quarter horse power motor runs at a speed of 600 rpm. Assuming 40% efficiency the work done by the motor in one rotation will be
7.46 J
7400 J
7.46 erg
74.6 J
Two bodies of masses 1 kg and 2 kg have equal momentum. Then, the ratio of their kinetic energies is
2 : 1
3 : 1
1 : 3
1 : 1
When a body moves in a circular path, no work is done by the force since
force and displacement are perpendicular to each other
the force is always away from the centre
there is no displacement
there is no net force
A.
force and displacement are perpendicular to each other
When a body moves on a circular path then force and distance are perpendicular to each other. Therefore, work done by the force is
W = F . d cos θ
= F . d cos 90° [ Since θ = 90°]
= 0 [Since cos 90° = 0]
A 5.0 amp current is setup in an external circuit by a 6.0 volt storage battery for 6.0 minutes. The chemical energy of the battery is reduced by
1.08 × 104 J
108 × 104 J
1.8 × 104 J
18 × 104 J
The relationship between the force F and position x of a body is as shown in figure. The work done in displacing the body from x = 1 m to x = 5 m will be
30 J
15 J
25 J
20 J