Data:
h = 2m
m = 45 Kg
PE = ? (Joule)
Adopting, gravity (g) ≈ <span>9,8 m/s²
</span>
Formula:

Solving:



Answer:
<span>
The sled's potential energy is 882 Joules</span>
Answer:
1: 19,6 N | 2: 686 N | 3: 705,6 N
Explanation:
Just apply the formula:
1: 2 . 9,8 = 19.6 N
2: (60+10) . 9,8 = 686 N
3: [30 + (6 . 7)] . 9,8
[30 + 42] . 9,8
72 . 9,8 = 705.6 N
Just sum all the weights in the system and then multiply by gravity (9,8 in this case)
You first need to convert the hours into minutes, then use the speed equals distance over time formula.