The correct answer would be 2: they transfer energy.
Answer:
The height is 
Explanation:
From the question we are told that
The combined mass of the child and the sled is 
The speed of the sled is 
Generally applying SOHCAHTOA on the slope which the combined mass is down from
Here the length of the slope(L) where the combined mass slides through is the hypotenuses
while the height(h) of the height of the slope is the opposite
Hence from SOHCAHTOA

=> 
Generally from the kinematic equation we have that

Here the u is the initial velocity of the combined mass which is zero since it started from rest
and a is the acceleration of the combined mass which is mathematically evaluated as


=> 
=> 
=> 
=> 
The bottom . I hope thats the answer you looking for. Let me know
Answer:
Landed before it explodes
Explanation:
vf = vi + at,
0 = 145 - (9.8)t,
t = 14.79 s (Time to reach highest point)
14.79 x 2 = 29.59 s (Time to land on the ground)
It will have landed before it explodes because both the time to reach the highest point and the time to land on the ground are less than 32 seconds.
Answer:
20.6 N
Explanation:
Friction equals normal force times coefficient of friction.
F = Fn μ
On level ground, normal force equal weight.
Fn = W
Therefore:
F = W μ
F = (685 N) (0.0300)
F = 20.6 N