10. A safe place to use the trebuchet would be away from other buildings and people. A good example of a place would be a large field with no nearby structures.
14. Many factors need to be kept consistent throughout the experiment. One example of a variable that would need to be consistent is the weight and size of the projectile.
15. It is important to do many trials so that you can make sure that the results of each trial are nearly the same. If they are all vastly different, then it means that something has gone wrong.
Sorry I was only able to answer a few questions, but I hope these few answers help! :)
Answer:
Current = 8696 A
Fraction of power lost =
= 0.151
Explanation:
Electric power is given by

where I is the current and V is the voltage.

Using values from the question,

The power loss is given by

where R is the resistance of the wire. From the question, the wire has a resistance of
per km. Since resistance is proportional to length, the resistance of the wire is

Hence,

The fraction lost = 
Answer:
Vehicles typically employ both hydraulic shock absorbers and springs or torsion bars. In this combination, "shock absorber" refers specifically to the hydraulic piston that absorbs and dissipates vibration.
Explanation:
hope this helps
F = m₁ a₁ = m₂ a₂
if m₁ = m and m₂ = 2m :
F = ma₁ = 2m a₂ ⇒ a₁ = 2 a₂
since v = at + v₀ with t = 3, v₀ = 0 ⇒ v = 3a:
v₁ = 2 v₂
since p = vm with v₁ = 2v and v₂ = v :
p₁ = v₁m₁ = 2v ⁻ m
p₂ = v₂m₂ = v ⁻ 2m
p₁ = p₂