A horizontal force of magnitude 35.9 N pushes a block of mass 4.07 kg across a floor where the coefficient of kinetic friction is 0.552. (a) How much work is done by that applied force on the block-floor system when the block slides through a displacement of 3.46 m across the floor? (b) During that displacement, the thermal energy of the block increases by 40.2 J. What is the increase in thermal energy of the floor? (c) What is the increase in the kinetic energy of the block? (a) Number (b) Number (c) Number i i ! Units J Units Units

Melinda is pushing a chair along a 5 meter straight path through her living room. She is standing, pushing at the top of the chair with a force of 30 newtons at a 22° angle of depression from the horizontal. (a) Calculate the work done in moving the chair. (b) How could Melinda re-arrange herself to make the energy use more efficient?

In the figure, a block of mass m = 3.70 kg slides head on into a spring of spring constant k = 370 N/m. When the block stops, it has compressed the spring by 13.0 cm. The coefficient of kinetic friction between block and floor is 0.300. While the block is in contact with the spring and being brought to rest, what are (a) the work done by the spring force and (b) the increase in thermal energy of the block-floor system? (c) What is the block's speed just as the block reaches the spring?

a block of mass m=5 kg is pulled at a constant speed along a rough horizontal surface by a rope at 30 degree. the tension in the rope is T and the coefficient of kinetic friction between the block and the surface is 0.25. (a) find the tension in the rope. (b) if the block travels a distance of 4.5 m along the surface, what is the work done by the tension force from the rope? (c) find the work done by friction on the rock.

A 0.32-kg particle has a speed of 5.0 m/s at point A and kinetic energy of 8.1 J at point B. (a) What is its kinetic energy at A? (b) What is its speed at point B? m/s (c) What is the total work done on the particle as it moves from A to B?

A horizontal force of magnitude 41.3 N pushes a block of mass 3.92 kg across a floor where the coefficient of kinetic friction is 0.576. (a) How much work is done by that applied force on the block-floor system when the block slides through a displacement of 4.79 m across the floor? (b) During that displacement, the thermal energy of the block increases by 40.5 J. What is the increase in thermal energy of the floor? (c) What is the increase in the kinetic energy of the block? (a) Number i Units (b) Number i Units (c) Number i Units

A motorcyclist runs out of gas on a level road 250 m from the gas station. She pushes the 220-kg motorcycle with a constant force of 150 N. How much work does she do?   For the motorcycle of the previous problem, if it was moving with a kinetic energy equal to the work done on it, how fast would it move?

A cheerleader lifts his 68 kg partner straight up off the ground a distance of 0.72 m before releasing her. Assume the partner’s velocity is zero at the beginning and the end of the lift. The acceleration of gravity is 9.8 m/s2 . If he does this 22 times, how much work has he done? Answer in units of J.

A horizontal force of magnitude 40.1 N pushes a block of mass 3.85 kg across a floor where the coefficient of kinetic friction is 0.553. (a) How much work is done by that applied force on the block-floor system when the block slides through a displacement of 4.78 m across the floor? (b) During that displacement, the thermal energy of the block increases by 38.0 J. What is the increase in thermal energy of the floor? (c) What is the increase in the kinetic energy of the block?

A different robot begins pushing a 10kg box that was already moving at 0.5m/s [Right] along a surface with a coefficient of kinetic friction of 0.15. The robot pushes with only 3N [Right] of force. What is the acceleration of the box?  Using the Work-Energy theorem, calculate how much work the robot does on the box accelerating it from 0.5m/s [Right] to 2m/s [Right]. What distance did the robot push the box? Use kinematics to check your work.