Advertisements
Advertisements
प्रश्न
A bullet of mass 50 g is moving with a velocity of 500 m s-1. It penetrated 10 cm into a still target and comes to rest. Calculate:
- the kinetic energy possessed by the bullet, and
- the average retarding force offered by the target.
उत्तर
(a) Mass of bullet = 50g = `50/1000 = 1/20 kg`
Velocity = 500 m/s
∴ K.E. of bullet = `1/2 mv^2`
= `1/2 xx 1/20 xx 500 xx 500`
K.E. = 6250 J
(b) u = 500 m/s, v = 0 as bullet comes to rest
distance covered = 10 cm = `10/100 = 1/10 m`
v2 - u2 = 2aS
0 - 500 × 500 = `2a × 1/10`
∴ a = - 1250000 m/s-2
∴ Retardation = 1250000 m/s-2
But F = m × a
∴ Retarding force offered by target = `1/20 xx 1250000`
F = 62500 N
APPEARS IN
संबंधित प्रश्न
Certain force acting on a 20 kg mass changes its velocity from 5 m s-1 to 2 m s-1. Calculate the work done by the force.
Kinetic energy = 1/2 × mass × ............
Define the term kinetic energy. Give one example of a body which possesses kinetic energy.
Two bodies of equal masses are moving with uniform velocities v and 2v. Find the ratio of their kinetic energies.
If the speed of a body is halved, what will be the change in its kinetic energy?
On a level road, a scooterist applies brakes to slow down from a speed of 10 m/s to 5 m/s. If the mass of the scooterist and the scooter be 150 kg, calculate the work done by the brakes. (Neglect air resistance and friction)
When a ball is thrown inside a moving bus, does its kinetic energy depend on the speed of the bus? Explain.
Find out the form of energy possessed by the following thing.
A rolling ball
Find out the form of energy possessed by the following thing.
Water falls
Find the kinetic energy of a body of mass 5 kg moving with a uniform velocity of 10 m s-1.
