M = mass of the girl = 53.4 kg
m = mass of skateboard = 3.55 kg
V' = velocity of the combination of girl and skateboard before she jumps forward = 0 
V = velocity of the girl forward = 1.32
v = velocity of the skateboard afterward = ?
Using conservation of momentum
(M + m) V' = MV + m v
inserting the values
(53.4 + 3.55) (0) = (53.4) (1.32) + (3.55) v
v = - 19.86
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Gravity is pushing you down on the earth while the friction from the ground is pushing you up. Those are the two frictions you must overcome when walking.
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Answer: Lightning is mostly light and electricity, this light that is hitting is going at a rate of 299,792.458 km per second (or 186,282 miles per second) this is so much compared to sound which only travels at about 761 mph (or approximately 332 meters per second). Fun fact: The lightening you are seeing is that coming back to the cloud because the process happens so fast.
Explanation:
The answer is b, anything that has mass and takes up space
There is no theoretical OR observational evidence for that statement.
