The person walking down the sidewalk follows the newton's third law of motion.
Explanation:
- A person is able to walk down the sidewalk by using the reaction forces from the ground.
- In simple term, feet pushes the ground and the reaction forces makes the feet able to walk.
- Another important force included in the walking mechanism is friction. With out friction one cannot walk down the sidewalks.
- Hence the forces involved in the walking of a person down the sidewalk are:
- Friction force
- Action and reaction force between ground and person's feet.
I think because water gives pressure and if u go even deeper theres more pressure
Heat required to raise the temperature of water is given as

here we have
m = 100 g = 0.100 kg
s = 4183 J/kg C

now we can use the above equation


so here it requires 20920 J heat to raise the temperature of 100 g water by 50 degree C
It is 7.4x(10 to the power of 7)