Answer:
They typically "want" 2, so the answer is C.
Explanation:
The gravitational potential energy:
E p = m x g x h
where m is the mass and h is the height;
m = 50 kg, g = 9.81 m/s² , h = 40 m
E p = 50 kg x 9.81 m/s² x 40 m
Answer:
E p = 19,620 J = 19.62 kJ
Answer:
40 s
Explanation:
After 10 seconds, the first skater would have a 8m/s * 10s = 80 m head start
Let t be the number of seconds after the second skater starts will the second skater overtake the first skater
The distance traveled by the first skater after t seconds is

Similarly the distance traveled by the 2nd skater after t seconds is

Since the 2nd skater catches up to the 1st one after 80 m behind, the distance traveled by the 2nd one must be 80m greater than the distance of the 1st skater

We can substitute 



Answer:
80 J
Explanation:
PE = mgh
PE = (4 kg)(9.8 m/s^2)(2 m)
PE = 78.4 J and with sig figs, it would be 80 J