Answer:
Your answer is D It does not need to be repeatable.
the reason for this is because C is correct.
You need to be able to experiment on something multiple times so that you can gather further data to imbedded your evidence in facts.
Answer:

Explanation:
The torque applied by a force can be calculated as

where
F is the magnitude of the force
d is the length of the arm
is the angle between the direction of the force and the arm
In this problem, we have
F = 15 N
d = 2.0 m

Substituting into the equation, we find

Answer:
Yes
Explanation:
Because if you push it, the skateboard has kinetic/potential energy.