A 10 kg block is slid horizontally across a floor with an initial speed of 10 m s−1 . The frictional force acting on the block has a magnitude of 100 N. (a) What is the initial kinetic energy of the block? (b) What is the initial gravitational potential energy of the block? (c) What is the final kinetic energy of the block? (d) What is the final gravitational potential energy of the block? (e) What is the change in the total energy of the block? (f ) How far does the block slide

When an automobile moves with constant speed down a highway, most of the power developed by the engine is used to compensate for the mechanical energy loss due to frictional forces exerted on the car by the air and the road. If the power developed by the engine is 195 hp, estimate the total friction force acting on the car when it is moving at a speed of 30 m/s. One horsepower equals 746 W.

A 5.80-kg block is set into motion up an inclined plane with an initial speed of v₁ = 8.20 m/s (see figure below). The block comes to rest after traveling d = 3.00 m along the plane, which is inclined at an angle of 0 = to the horizontal. V. (a) For this motion, determine the change in the block's kinetic energy. (b) For this motion, determine the change in potential energy of the block-Earth system. (c) Determine the friction force exerted on the block (assumed to be constant). N (d) What is the coefficient of kinetic friction?

What average mechanical power (in W) must a 60.0 kg mountain climber generate to climb to the summit of a hill of height 365 m in 49.0 min? Note: Due to inefficiencies in converting chemical energy to mechanical energy, the amount calculated here is only a fraction of the power that must be produced by the climber's body. HINT

A 7.80-g bullet moving at 560 m/s penetrates a tree trunk to a depth of 4.80 cm. (a) Use work and energy considerations to find the average frictional force that stops the bullet. (b) Assuming the frictional force is constant, determine how much time elapses between the moment the bullet enters the tree and the moment it stops moving.

A motorcyclist drives up a 3.1-meter tall ramp and leaves the ramp with a speed of 42.5 m/s.  If his speed is 37.8 m/s when he reaches the peak of his path, what is the maximum height (in m) above ground that he reaches? (Use energy, not kinematic equations.)

You throw a tennis ball (mass 0.0570 kg) vertically upward. It leaves your hand moving at 15.0 m/s. Air resistance cannot be neglected, and the ball reaches a maximum height of 8.00 m. (a) By how much does the total mechanical energy decrease from when the ball leaves your hand to when it reaches its maximum height? (b) What is the magnitude of the average force of air resistance?

A 7.80-g bullet moving at 640 m/s penetrates a tree trunk to a depth of 6.10 cm. (a) Use work and energy considerations to find the average frictional force that stops the bullet. (b) Assuming the frictional force is constant, determine how much time elapses between the moment the bullet enters the tree and the moment it stops moving.

A 35 kg sled slides along a horizontal surface on which the coefficient of kinetic friction is 0.25. Its velocity at point A is 10.0 m/s, and its velocity at point B is 2.0 m/s. You must use Work/Energy methods (not Kinematics). (a) What is the frictional force acting on the sled? (b) How much work is done on the sled by friction over the displacement ∆x = xB − xA? (c) What is the distance the sled travels between A and B?

What average mechanical power (in W) must a 61.5 kg mountain climber generate to climb to the summit of a hill of height 405 m in 46.0 min? Note: Due to inefficiencies in converting chemical energy to mechanical energy, the amount calculated here is only a fraction of the power that must be produced by the climber's body.