A body of mass 3 kg is under a constant force which causes a displacement s in metre in it, give by the relation
where t is in second. Work done by the force is 2s is
A shell of mass 200 gm is ejected from a gun of mass 4kg by an explosion that generates 1.05 kJ of energy. The initial velocity of the shell is
100 ms-1
80 ms-1
40 ms-1
120 ms-1
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
zero
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
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 body of mass 1kg is thrown upward with a velocity 20 ms-1.It momentarily comes to rest after attaining a height of 18m. How much energy is lost due to air friction ? ( g = 10 ms-2)
20 J
30 J
40 J
10 J.
A force F acting on an object varies with distance x as shown here. The force is in newton and x is in metre. The work done by the force in moving the object x = 0 to x = 6m is
4.5 J
13.5 J
9.0 J
18.0 J
A child swinging a swing. Minimum and maximum heights of swing from earth’s surface are 0.75 m and 2m respectively. The maximum velocity of this swing is
5 m/s
10 m/s
15 m/s
20 m/s
The identical balls A and B moving with velocities + 0.5 m/s and -0.3 m/s respectively collide head on elastically. The velocity of the balls A and B after collision will be respectively
+ 0.5 m/s and +0.3 m/s
-0.3 m/s and +0.5 m/s
+0.3 m/s and 0.5 m/s
-0.5 m/s and +0.3 m/s
Two masses 1g and 9g are moving with equal kinetic energies. The ratio of the magnitudes of their respective linear momenta is
1 : 9
9 : 1
1 : 3
3 : 1
