A hoop of radius 2 m weighs 100 kg. It rolls along a horizontal floor so.that its centre of mass has a speed of 20 cm/s. How much work has to be done to stop it?

A 200 g ball falls from rest through air. If its speed is 10 m/s after having through a distance of 20m, how much energy was lost due to friction against air?

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 to the other (10 m away) with a speed of 4 m s^-1 relative to the trolley in a direction opposite to the its motion, and jumps out of the trolley. What is the final speed of the trolley? How much has the trolley moved from the time the child begins to run?

A body of radius R and mass m is rolling horizontally without slipping with a unifrom speed v. It then rolls up in an inclined plane to a maximum height of h. If h = (3v^2)/(4g) , determine the MI of the body about its axis of rotation.

A block of mass 4 kg irioving horizontally on a frictionless table at speed 2ms^(-1) compresses a spring through a distance 10 cm before its speed is halved. Find the spring constant of the spring.

How much work is done on a body of mass m in moving it around a horizontal circle of radius R?

A body of mass 2 kg initially at rest moves under the action of 0 an applied horizontal force of 7 N on a table with coefficient of kinetic friction= 0.1. Compute the work done by friction in 10 s,

Two heavy spheres each of mass 100 kg and radius 0.10 m are placed 1.0 m apart on a horizontal table. What is the gravitational force and potential at the mid point of the line joining the centers of the spheres? Is an object placed at that point in equilibrium? If so, is the equilibrium stable or unstable?

A person trying to lose weight (dieter) lifts a 10 kg mass, one , thousand times, to a height of 0.5 m each time. Assume that the potential energy lost each time she lowers the mass is dissipated, (a) How much work does she do against the gravitational force? (b) Fat supplies 3.8 xx 10^7 J of energy per kilogram which is converted to mechanical energy with a 20% efficiency rate. How much fat will the dieter use up?

A man of mass 70 kg stands on a weighing scale in a lift which is moving (a) upwards with a uniform speed of 10 m s^1 (b) downwards with a uniform acceleration of 5 m s^2, upwards with a uniform acceleration of 5 m s-^1z. What would be the readings on the scale in each case? What would be the reading if the lift mechanism failed and it hurtled down freely under gravity?

A body of mass 2 kg initially at rest moves under the action of 0 an applied horizontal force of 7 N on a table with coefficient of kinetic friction= 0.1. Compute the (a) work done by the applied force in 10 s, .