Question

A bullet with kinetic energy of 400J strikes a wooden block where a 8.00x10N resistive force stops the bullet what is the penetration of the bullet

Answer 1

The "penetration of the bullet" is 5 m

Explanation:

A "bullet" with "kinetic energy" of = 400J

A resistive force stops the bullet  = 8.00 x 10 N

Work = change in energy  

Work = ∆ Kinetic Energy   (equation 1)

Work = $F\times d$   (equation 2)

From equations 1 and 2 we have,

$F\times d$ = ∆ Kinetic Energy

Where ,

Kinetic Energy = 400 J

F = 8.00 x 10 N

(8.00 x 10 N) d = 400 J

(80 N) d = 400 J

$d=\frac{400}{80}$

d = 5 m

The penetration of the bullet is 5 m