A boy has a bag of sand of mass 20 kg . First of all, he keeps the bag on his head and moves 10 metre. Second time, he drags the bag through 10 metres on a frictionless surface. In which case, he does more work?

A 10 kg boy standing on a 40 kg boat floating on water is 20 m from the shore of the river. If the boy moves 8 m on the boat towards the shore, then how far is he from the shore.(Assume there is no friction between water and boat)?

A person trying to lose weight by burning fat lifts a mass of 10 kg up to a height of 1m 1000 times. Assume that the potential energy lost each time he lowers the mass is dissipated. How much fat will he use up considering the work done only when the weight is lifted up ? Fat supplies 3.8xx10^7J of energy with a 20% effciency rate.Take g=9.8m//s^2

To verify the cash balance, the auditor of Jaya Bank Ltd. Employs his assistant to count cash in hand of Rs. 4500. At first he counts @ Rs. 150 per minute for 10 minutes only, at the end of which time he begins to count @ Rs.2 less every minute than he did in the previous minute. Ascertain how much time he will take to count Rs. 4500 ?

A man has Rs 1500 to purchase rice and wheat. A bag of rice and a bag of wheat cost Rs 180 and Rs 120 respectively he has a storage capacity of 10 bags only . he earns a profit of Rs 11 and Rs 8 per bag of rice and wheat respectively. how many bags of each must he buy to makes maximum profit

A boy of mass 40 kg is climbing a vertical pole at a constant speed. If the coefficient of friction between his palms and the pole is 0.8 and g=10m//s^2 , the horizontal force that he is applying on the pole is

A trolley of mass 200 kg moves with a uniform speed of 36 km/h on a frictionless track. A child of mass 20 kg runs on the trolley from one end the other (10 m away) with a speed to 4m/s relative to the trolley in a direction opposite to the trolly's motion and jump out of the trolly. What is the final speed of the trolly? How much has the trolly moved from the time the child begins to run?