A person is pushing a wooden crate of mass m, = 20 kg at a constant speed vo = 1.2– for Ax = 3 m along a rough horizontal floor that has a coefficient of friction uz = .4.

At an accident scene on a level road, investigators measure a car’s skid mark to be 112 m long.  It was a rainy day and the coefficient of friction was estimated to be 0.42.  Use these data to determine the speed of the car when the driver slammed on (and locked) the brakes.

The coefficient of static friction µg between the 83-lb body and the 14° wedge is 0.37. Determine the magnitude of the force P required to begin raising the 83-lb body if (a) rollers of negligible friction are present under the wedge, as illustrated, and (b) the rollers are removed and the coefficient of static friction Hs = 0.37 applies at this surface as well. 83 lb 14° Answers: (a) P = i Ib (b) P = i Ib

A block of mass 1.96kg is accelerated across a rough surface by a rope passing over a pulley, as shown in the figure below. The tension in the rope is 14.0N, and the pulley is 10.8cm above the top of the block. The coefficient of kinetic friction is 0.350. Calculate the value of x at which the acceleration becomes zero.

I'm trying to find out number 17

An inclined plane making an angle of 25º with the horizontal has a pulley at its top. A 30kg  block on the plane is connected to a freely hanging 20kg block by means of a string passing  over the pulley. Compute the distance the 20kg block will fall in 2 second starting from rest.  Neglect friction.

A feather falls at constant velocity a vertical distance of 123.8 m. If the mass of the feather is 39.04 g then(a) how much is done by gravity, and (b) air resistance?

A small boat is being pushed up a ramp into the back of a flatbed truck. The boat is sitting at the top of the ramp, which is located 1.4 m above the ground. The boaters think the boat is safe there, and begin to walkaway. However, they have neglected the thin layer of ice that has formed on the ramp, which is angled at 30◦ up from the ground. Neglecting the friction between the boat and the ramp, how long do the boaters havebefore the boat reaches the bottom of the ramp?

Redo Example 5, assuming that there is no upward lift on the plane generated by its wings. Without such lift, the guideline slopes downward due to the weight of the plane. For purposes of significant figures, use 2.91 kg for the mass of the plane, 12.2 m for the length of the guideline, and 18.2 and 36.4 m/s for the speeds. (a) Number (b) Number Units Units

At an accident scene on a level road, investigators measure a car's skid mark to be 89 m long. It was a rainy day and the coefficient of friction was estimated to be 0.43. Use these data to determine the speed of the car when the driver slammed on (and locked) the brakes.