Answer:
(D) It is equal to the original velocity of the skater.
Explanation:
The velocity of the center of mass of a system is

The velocity of the center of mass is constant if there is no external force, because the total momentum of the whole system is conserved.
So, before the snowball is thrown, the velocity of the center of mass is equal to that of the skater. This velocity will always be equal to the velocity of the center of mass of the system.
Light will travel more slowly in a material with a higher index of refraction
79 m/s I belive.
I hope I'm not incorrect!
Answer:
7.4 J
Explanation:
m = mass of the ball = 0.160 kg
h = height gained by the ball = 4.70 m
g = acceleration due to gravity = 9.8 m/s²
U = Potential energy gained by the ball
Potential energy gained by the ball is given as
U = mgh
W = work done by student
Using conservation of energy
W = U
W = mgh
W = (0.160) (9.8) (4.70)
W = 7.4 J