A box of unknown mass is sliding with an initial speed v₁ = 4.30 m/s across a horizontal frictionless warehouse floor when it encounters a rough section of flooring d = 2.80 m long. The coefficient of kinetic frictio between the rough section of flooring and the box is 0.100. Using energy considerations, determine the final speed of the box (in m/s) after sliding across the rough section of flooring. m/s

In the figure, a block of mass m = 4.00 kg slides head on into a spring of spring constant k = 230 N/m. When the block stops, it has compressed the spring by 8.40 cm. The coefficient of kinetic friction between block and floor is 0.480. 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) Number -0.81 (b) Number 1.6 (c) Number i -1.1 Units J Units J Units m/s

4. This Olympic skeleton athlete slides down an icy track head first. The track has many twists and turns with a total height of 102.75 m. If the 99.375 kg man has a speed of 27 m/s at the bottom, what was the total work done on him by friction and air resistance slowing him down? (In other words, what was the energy lost to friction and air resistance?) He starts from rest at the top. 6.3843e4 Previous submissions: -63.84 63.84 63843 J J incorrect

A 1100 kg car drives up a hill that is 16.2m high. During the drive, two nonconservative forces do work on the car: (i) the force of friction, and (ii) the force generated by the car's engine. The work done by friction is −2.91×105J; the work done by the engine is 6.74×105JFind the change in the car's kinetic energy from the bottom of the hill to the top of the hill

8. A 55-kg skateboarder enters a ramp moving horizontally with a speed of 6.5 m/s, and leaves the ramp moving vertically with a speed of 4.1 m/s. (A) Find the height of the ramp, assuming no energy loss to frictional forces. (B) What is the skateboarder's maximum height above the bottom of the ramp?

In order to test energy principles, I decide to do the following experiment with my son at the playground. I push him on a swing so that his initial velocity, at the low point of the arc, is vi=8.0 m/s. His mass is 25kg How high will he swing? Ignoring air resistance, how high will he swing on the other side of the arc?

A hockey puck of mass 0.26 kg is sliding along a slippery frozen lake, with an initial speed of 64 m/s. The coefficient of friction between the ice and the puck is eventually causes the puck to slide to a stop. Find the work done by friction. J = 0.031. Friction

A child on a sled is initially at rest on an icy horizontal surface. The sled is pushed until it reaches a final velocity of 6.05 m/s in a distance of 15.6 m. The coefficient of friction between the ice and runners of the sled is 0.200, and the weight of the child and the sled is 375 N. Find the work done by the force pushing the sled.

When a car is moving at constant speed, the developed potential is used to overcome the frictional forces exerted by the air and the road. If the power developed by the motor is 50.0 hp, what is the total frictional force acting on the car at 24.6 m / s? 1 hp = 746 W.

A child on a sled is initially at rest on an icy horizontal surface. The sled is pushed until it reaches a final velocity of 6.60 m/s in a distance of 12.8 m. The coefficient of friction between the ice and runners of the sled is 0.200, and the weight of the child and the sled is 335 N. Find the work done by the force pushing the sled.