Question

A bullet traveling horizontally at a speed of 350 m/s hits a board perpendicular to the surface, passes through it, and emerges on the other side at a speed of 210 m/s. if the board is 4.00 cm thick, how long does the bullet take to pass through it? (assume a constant deceleration as the bullet passes through the board.

Answer 1

The average speed of the bullet as it travels through board,

`v=(350 m/s+210 m/s)/(2) =280 m/s`

As the speed of the bullet decreases linearly in the board, therefore the time of the bullet travels through the board is

`t= (distance)/(v_(ave) )`

As the board is 4.0 cm ( 0.04 m) thick, therefore

`t= (0.04 m)/(280 m/s) =1.43 * 10^(-4) s`

Thus, the time taken by the bullet to pass the board is
`1.43 * 10^(-4) s`.