warm fluids are less dense than cold fluids
Answer:
Explanation:
She's correct but doesn't mean the wagon cannot put into motion. The force that she applied on the wagon, according to Newton's 2nd law, would have generated an acceleration, which translates into motion. The reaction force the wagon applies on her due to Newton's 3rd law, would not hinder its own motion.
As per the question the mass of the boy is 50 kg.
The boy sits on a chair.
We are asked to calculate the force exerted by the boy on the chair at sea level.
The force exerted by boy on the chair while sitting on it is nothing else except the force of gravity of earth i.e the weight of the body .The direction of that force is vertically downward.
At sea level the acceleration due to gravity g = 9.8 m/s^2
Hence the weight of the boy 
[m is the mass of the body]
we have m = 50 kg.
Hence w = 50 kg ×9.8 m/s^2
=490 N kg m/s^2
= 490 N
Here newton [N] is the unit of force.
Thus, more than 30 J of potential energy can be loosed by the ball. Thus, the gravitational potential energy of the ball is more than 30 J.
If there is no air resistance, the ball's potential energy is entirely transformed into kinetic energy. When air resistance is taken into account, a portion of the potential energy is used to overcome it. Thus, AU > AKE. In the current scenario, a ball gains 30 J of kinetic energy while falling and is treated as encountering air resistance. The energy that an object retains due to its position in relation to other objects, internal stresses, electric charge, or other factors is known as potential energy in physics. The potential energy will be transformed into kinetic energy if the stones fall. High on the tree, branches have the potential to fall, which gives them energy. Chemical potential energy exists in the food we eat.
Learn more about potential energy here:
brainly.com/question/24284560
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