The boy’s foot causes the motion. His foot is the one that causes the ball to roll down the hill.
example force. because you can say" I applied 3 newtons downward to the floor".
force has magnitude and direcion
Answer:
Explanation:
Given





R for Helium 

mass of gas 


Similarly
can be found


Work done 


Since it is a polytropic Process
therefore 






From Energy balance
Neglecting kinetic and Potential Energy change

Change in Internal Energy 




i.e. Heat is being removed