Hypothesis means <span>a supposition or proposed explanation made on the basis of limited evidence as a starting point for further investigation</span>
Answer:
C. The floor pushing back against the foot
Explanation:
The mass of the football player is 250 kg.
<u>Explanation:</u>
Momentum is defined as the product of mass and velocity. So here the velocity (v) is given as 10 m/s and the momentum is given as 2500 kg m /s. So we can determine the mass (m) of the player by substituting the known terms in the formula of determining momentum as shown below.

As we know the value of momentum and velocity, the mass can be found as,

Thus, the mass of the football player is found to be 250 kg.
The formula for a kinetic energy KE of a falling body is
KE = mgh
where m = mass, g = acceleration due to gravity (9.8 m/s^2, constant), h = height.
The total mass of a skateboader and a skateboard is 64 + 2.0 = 66 kg.
Finally,
KE = 66*9.8*5.0 = 32340 J
I’m pretty sure it’s, B. An Electric Motor. I apologize in advance if it’s incorrect.