Physics Momentum Question

Question

9. A 0.05 kg bullet moving vertically upwards at 125 m/s hits a stationary 2.6 kg block hanging from a 5.00 m long string. The block then soars upward until it reaches a maximum height (you may assume that the bullet remains within the sandbag).
a) What physics concept applies for the collision between the bullet and the block? Calculate the speed the block has immediately after the collision.



b) What kind of energy does the block have after the collision? Where does this energy go once it soars into the air and reaches its maximum height?



c) Calculate the maximum height reached by the block.

Answer 1

a) conservation of momentum.

m1v1+m2v2=mv

0.05 x 125 + 0= 2.65 x v

=> v=2.36 m/s

 

b) kinetic energy after collision, potential energy once at maximum height

 

c)2as=vf ² -v0 ²

 

2 x 9.8 x s=(2.36)²

 s=0.28 m