Question

A bullet of mass 10g travelling horizontally with a velocity of 150m/s strikes a stationary wooden block and cones to rest in 0.03s calculate the distance of penetration of the bullet into the block.also calculate the magnitude of the force exerted by the wooden block on the bullet

Answer 1

Here , Given in the question ,

Mass , m = 10 g⇒0.01 kg

Final velocity of the bullet v = 0

Initial velocity of the bullet , $u = 150 m/sec.$

here,  time  = 0.03sec ( which is taken by the bullet )

Now for calculating the penetration distance Let = s

We know the formula ,

v = u + at

⇒0 = 150+ a (0.03)

⇒a = -5000 m/sec²

(negative sign showing retardation here ) .

∴ v² = u² +2as

⇒0 = 150²+ 2× (-5000) × s

⇒s = 2.25 m

Hence 2.25 is the penetration distance of the bullet.

Now for the magnitude of the force,

Magnitude of the force  |F | = m |a|

|F | = 0.01 × 5000

⇒ Force, F = 50 N.

Hence 50 N is the force exerted by the block.

Hope it helps .