Advertisements
Advertisements
प्रश्न
A girl riding a bicycle along a straight road with a speed of 5 ms–1 throws a stone of mass 0.5 kg which has a speed of 15 ms–1 with respect to the ground along her direction of motion. The mass of the girl and bicycle is 50 kg. Does the speed of the bicycle change after the stone is thrown? What is the change in speed, if so?
उत्तर
Given, the total mass of girl, bicycle and stone = m1 = (50 + 0.5) kg = 50.5 kg.
Velocity of bicycle u1 = 5 m/s, Mass of stone m2 = 0.5 kg
Velocity of stone u2 = 15 m/s, Mass of girl and bicycle m = 50 kg
Yes, the speed of the bicycle changes after the stone is thrown.
Let after throwing the stone the speed of bicycle is v ms.
According to the law of conservation of linear momentum,
m1u1 = m2u2 + mv
50.5 × 5 = 0.5 × 15 + 50 × v
252.5 – 7.5 = 50 v
or v = `245.0/50`
v = 4.9/m/s
Change in speed = 5 – 4.9 = 0.1 m/s.
APPEARS IN
संबंधित प्रश्न
A hockey ball of mass 200 g travelling at 10 m s−1 is struck by a hockey stick so as to return it along its original path with a velocity at 5 m s−1. Calculate the change of momentum occurred in the motion of the hockey ball by the force applied by the hockey stick.
What is the SI unit of momentum ?
state whether momentum is scalar or vector.
What is the total momentum of the bullet and the gun before firing ?
Fill in the following blanks with suitable words :
In collisions and explosions, the total _____________ remains constant, provided that no external _____________ acts.
A 150 g ball, travelling at 30 m/s, strikes the palm of a player’s hand and is stopped in 0.05 second. Find the force exerted by the ball on the hand.
Explain why it is possible for a small animal to fall from a considerable height without any injury being caused when it reaches the ground.
A ball X of mass 1 kg travelling at 2 m/s has a head-on collision with an identical ball Y at rest. X stops and Y moves off. Calculate the velocity of Y after the collision.
A heavy car A of mass 2000 kg travelling at 10 m/s has a head-on collision with a sports car B of mass 500 kg. If both cars stop dead on colliding, what was the velocity of car B ?
Two blocks P and Q of masses 0.3 kg and 0.4 kg, respectively, are stuck to each other by some weak glue as shown in the figure. They hang together at the end of a spring with a spring constant of k = 200 N/m. The block Q suddenly falls free due to the failure of glue, then the maximum kinetic energy of block P during subsequent motion will be ______ mJ.
