300 J of work is done in sliding a 2kg block up an inclined plane of height 10 m. Taking g = 10 m/s2, work done against friction is
200 J
100 J
zero
1000J
A stone is thrown at an angle of 45o to the horizontal with kinetic energy K. The kinetic energy at the highest point is
K
A body of mass m moving with velocity 3 km/h collides with a body of mass 2m at rest. Now the coalesced mass starts to move with a velocity
1 km/h
2 km/h
3 km/h
4 km/h
A bullet of mass 10g leaves a rifle at an initial velocity of 1000m/s and strike the earth at the same level with a velocity of 500m/s. The work done in joule to overcome the resistance of air will be
375
3750
5000
500
Water falls from a height of 60 m at the rate of 15kg/s to operate a turbine. The losses due to frictional forces are 10% of energy. How much power is generated by the turbine? (Take g = 10 m/s2)
8.1 kW
10.2 kW
12.3 kW
7.0 kW
A force acts on a 3.0 g particle in such a way that the position of the particle as a function of time is given by x = 3 t – 4 t 2 + t 3, where x is in meter and t in second. The work done during the first 4 s is
570 mJ
450 mJ
490 mJ
528 mJ
Two bodies with kinetic energies in the ratio 4 : 1 are moving with equal linear momentum. The ratio of their masses is
1 : 2
1 : 1
4 : 1
1 : 4
A bomb of mass 30kg at rest explodes into two pieces of masses 18kg and 12kg. The velocity of 18kg mass is 6ms-1. The kinetic energy of the other mass is
256 J
486 J
524 J
324 J
The KE acquired by a mass m in traveling a certain distance d, starting from rest, under the action of a constant force is directly proportional to
m
independent of m
A stationary particle explodes into two particles of masses m1 and m2 which move in opposite directions with velocities v1 ad v2. The ratio of their kinetic energies E1 / E2 is
1