Question

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 .

Answer 1

v₂ = 3.44 m/s

Step-by-step 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