Question

A bullet moves with a speed 150 m/s strikes and penetrates 3.5cm before stopping. find the magnitude of its acceleration.

Answer 1

initial speed, u = 150 m/s

final speed, v = 0

distance travelled, s = 3.5cm = 0.035 m

acceleration,a = ?

we know that v² - u² =2as

⇒ 0 - 150² = 2×a×0.035

⇒ -22500 = 0.07a

⇒ a = -22500/0.07

⇒ a = -321428.6 m/s²

Acceleration is -321428.6 m/s².

Answer 2

v²=  u²+ 2as

0  =   150²+2×a×0.035

-22500 = 0.07a

a = -22500/0.07

a = -321428.6 m/s²

therefore acceleration is -321428.6 m/s²