Dan is gliding on his skateboard at 2.00 m/s . he suddenly jumps backward off the skateboard, kicking the skateboard forward at 7.00 m/s (as measured by an observer on the ground). dan's mass is 40.0 kg and the skateboard's mass is 7.00 kg .

The velocity of Dan is 1.13 m/s.

Explanation:

Given that,

Initial velocity of skateboard and Dan = 2.00 m/s

Velocity of skateboard = 7.00 m/s

Mass of Dan m= 40.0 kg

Mass of skateboard M= 7.00 Kg

Suppose How fast is Dan going as his feet hit the ground?

We need to calculate the initial velocity of Dan

Using conservation of momentum

Put the value into the formula

Hence, The velocity of Dan is 1.13 m/s.

d. air pressure decreases as altitude increases.

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