Dan is gliding on his skateboard at 4.00 m/s. He suddenly jumps backward off the skateboard, kicking the skateboard forward at 8.00 m/s. Dan's mass is 50.0 kg and the skateboard's mass is 7.00 kg.

v₂ = 3.44 m/s

Explanation:

given,

Dan is gliding on skateboard at = 4 m/s

speed of skateboard = 8 m/s

mass of Dan = 50 Kg

mass of skateboard = 7 Kg

Speed of Dan when his feet hit the ground = ?

Using conservation of momentum

PE (initial) = PE (final)

(M+m) V = m v₁ + M v₂

(50+7) x 4 = 7 x 8 + 50 x v₂

50 x v₂ = 172

v₂ = 3.44 m/s

speed of Dan when his feet hit the ground = v₂ = 3.44 m/s