Question

A bullet leaves a rifle with velocity 200m/s and strike a wooden target up to 4 cm. What velocity

Answer 1

KE= work done

mv^2/2= F *s

m200*200/2= F*4/100

F/m= 200*200*100/8( the retardation produced in the wooden peg.

Now to pierce 16 cm

m*v^2/2= m*4000000/8 *16/100

v^2/2= 80000

v^2= 160000

v= 400 m/s. answer.

Answer 2

Answer:

V¹=200m/s , s=4cm=4/100m

Kinetic energy=work done

(or) mv²/2=Fs

(or) m×200×200/2=F×4/100(retardation of the bullet

(or) F/m=200×200×100/4×2

Pierce 16cm=16/100m

mv²=m×200×200×100×16/4×2×100

(or) v²=m×80000×2/m

(or) v=400m/s