Some examples of when friction is helpful are: to help the movement of tires. When you walk, and also, when you erase. :)
When you are in free fall, the force of gravity is stronger than your velocity perpendicular to where you're falling, and you move at a constant speed downwards.
Under feelings of weightlessness, you are still being pulled by gravity, but your perpendicular velocity and distance from the source can cancel each other out.
Answer:
The lose of thermal energy is, Q = 22500 J
Explanation:
Given data,
The mass of aluminium block, m = 1.0 kg
The initial temperature of block, T = 50° C
The final temperature of the block, T' = 25° C
The change in temperature, ΔT = 50° C - 25° C
= 25° C
The specific heat capacity of aluminium, c = 900 J/kg°C
The formula for thermal energy,
<em>Q = mcΔT</em>
= 1.0 x 900 x 25
= 22500 J
Hence, the lose of thermal energy is, Q = 22500 J
The correct answer is C) Rainfall
