Question

a bullet is fired onto a wall with a velocity of 50 M per second if the bullet stops at the depth of 10cm inside the wall find the retardation produced by the wall
ans:12.5km/s²

Answer 1

initial velocity u= 50 m/s

distance traveled s =10 cm = 10/100 =0.1 m

final velocity v= 0 m/s

By equations of motion ,

v^2-u^2 = 2as

0- ( 50 )^2 =2 x a x 0.1

-2500 = 2 x a x 0.1

a= -2500/2 x 0.1 = - 12500 =  -12.5 km/s^2

hence retardation is 12.5 km/s^2

Answer 2

=>initial velocity is 50m/s
=>it stopped after firing so, final velocity will be 0m/s
=>distance is 10cm =0.1m

v²=u² +2as
0²=50² + 2*a*0.1
0= 2500+0.2a
0.2a= -2500
a= -2500/0.2
a= -12500m/s²
a=-12.5km/s²

this opposite retardation acceleration can also be written as 12.5km/s²
hope it helps you:)