Answer:
0.28 J
Explanation:
Since the air-hockey puck was initially at rest
KE₀ = initial kinetic energy of the air-hockey puck = 0 J
KE = final kinetic energy of the air-hockey puck
m = mass of air-hockey puck 0.5 kg
F = net force = 0.4 N
d = distance moved = 0.7 m
Using work-change in kinetic energy
F d = (KE - KE₀)
(0.4) (0.7) = KE - 0
KE = 0.28 J