Question

A bullet of mass 50g is fired with a velocity 400m/s strikes a wall and goes out with a velocity 100m/s. Calculate the work done passing through the wall

Answer 1

Explanation:

work done = 1/2×(400^2-100^2)×0.05

= 1/2×150000×0.05

= 75000×0.05

= 37500 J

Answer 2

Answer:

3750 J

Explanation:

Mass of the bullet = 50g or 50×10^-3 kg

Initial velocity (u) = 400 m/s

Final velocity (v) = 100 m/s

From the Newton's third law of motion, we know that

v^2 = u^2 + 2as

( where a is the acceleration and 's' s displacement )

Putting the values we get

100^2 = 400^2 + 2 F/m * s. ( acceleration = force / mass )

10000 = 160000 + 2 w / m. ( work done = force * displacement )

( -150000 ) = ( 2 w ) / 50*10^-3

2 w = - 7500000 * 10^-3

2 w = - 7500

w = - 3750 J

Hope it helps you negative sign shows that force is equal and opposite.

Thanks