B. only its velocity should change
The answer should be B. only it's velocity.
Answer:
4.2 m/s
Explanation:
Momentum is conserved.
m₁u₁ + m₂u₂ = m₁v₁ + m₂v₂
(35 g) (9 m/s) + (75 g) (-7 m/s) = (35 g) (-15 m/s) + (75 g) v
315 g m/s − 525 g m/s = -525 g m/s + (75 g) v
315 g m/s = (75 g) v
v = 4.2 m/s
Hooke's Law
k = spring constant
x = stretch
F = force
Input the value
Work = power × time
W = (6000 W) (7.5 s)
W = 45,000 J