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3.Which of the followings works on the principle of momentum?
(a)A gun recoils after firing
(b)Rocket
(c)The case of hose pipe
(d)All the above

4.A boy of mass 50 Kg running at 5 m/s jumps on to a 20Kg trolley travelling in the same direction
at 1.5 m/s. What is the common velocity?
(a) 4m/s
(b) 3 m/s
(c)3.5 m/s
(d) None of the above

5. A body of mass M moving with velocity V explodes into two equal parts. If one comes to rest and
the other body moves with velocity v, what would be the value of v?
(a)V (b)V/ 2

(c) 4 V (d)2V
6. A body of mass 0.25 kg is projected with muzzle velocity 100 m/s from a tank of mass 100 kg.
What is the recoil velocity of the tank?
(a) 5 m/s (b) 25 m/s

(c) 0.5 m/s (d) 0.25 m/s
7. A bullet of mass 10 g is fired from a gun of mass 1 kg. If the recoil velocity is 5 m/s, the velocity of
the muzzle is
(a) 0.05 m/s (b) 5 m/s

(c) 50 m/s (d) 500 m/s

SUBJECTIVE

1. Why does a gun recoil on firing a bullet?(BOARD)
2.Two boys having the same mass are standing on ice-skates at some distance apart on a
frictionless surface. A rope is fastened around the body of a boy,the other end of which is in the
hand of the second boy. What would happen if the second boy pulls the rope? (HOTS)
NUMERICALS
1. Two objects of masses 100 g and, 200 g are moving along the same line and direction with
velocities of 2 m/s and 1 m/s respectively.They collide and after the collision the first object moves
at a velocity of 1.67 m/s. Determine the velocity of the second object.(BOARD)

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2. A 30 kg shell is flying at 48 ms . When it explodes, its one part, of 18 kg stops, while the
remaining part flies on. Find the velocity of the later?(AVG)