A coffee cup on the horizontal dashboard of a car slides forward when the driver decelerates from 45 km/h to rest in 3.5 s or less, but not if she decelerates in a longer time.What is the coefficient of static friction between the cup and the dash? Assume the road and the dashboard are level (horizontal).

A hockey puck (mass = 2 kg) leaves the players stick with a speed of 20 m/s and slides on the ice before coming to rest.The coefficient of friction between the puck and the ice is 0.9. How far will the puck slide after leaving the players stick? m

You are helping a friend move. Consider two boxes which have masses in factors ofm; one of mass 6m and the other of mass 7m. The coefficient of static friction betweenthe two boxes is very large. The coefficient of static friction between the boxes and thefloor is 0.7 and the coefficient of kinetic friction is 0.1. You place the large box on top ofthe small box and slide them down a 1m high ramp out of the truck. The ramp isfrictionless because it is covered with wheels. The box slides down this ramp smoothlyonto the horizontal grass with coefficient of kinetic friction is 0.142857142857143. Howfar (in meters) will the boxes slide before they stop?

In a movie, a stuntman places himself on the vertical front of a truck as the truck accelerates. The coefficient of static friction between the stuntman and the truck is 0.370. The stuntman is not standing on anything but can “stick” to the front of the truck as long as the truck continues to accelerate. What minimum forward acceleration will keep the stuntman on the front of the truck?

The 118-lb force P is applied to the 250-lb crate, which is stationary before the force is applied. Determine the magnitude and direction of the friction force F exerted by the horizontal surface on the crate. The friction force is positive if to the right, negative if to the left. Assume ??= 0.48, ??= 0.38.

Seat belts and air bags save lives by reducing the forces exerted on the driver and passengers in an automobile collision. Cars are designed with a "crumple zone" in the front of the car. In the event of an impact, the passenger compartment decelerates over a distance of about 1 m as the front of the car crumples. An occupant restrained by seat belts and air bags decelerates with the car. By contrast, an unrestrained occupant keeps moving forward with no loss of speed (Newton's first law!) until hitting the dashboard or windshield. These are unyielding surfaces, and the unfortunate occupant then decelerates over a distance of only about 5 mm. Part A A 65 kg person is in a head-on collision. The car's speed at impact is 13 m/s. Estimate the net force on the person if he or she is wearing a seat belt and if the air bag deploys. Express your answer to two significant figures and include the appropriate units. Fnet = 7293 Submit CHμA Part B X Incorrect; Try Again Fnet = Previous Answers…

A man is driving his car with speed 49.0 mi/h on a horizontal stretch of road. (a) When the road is wet, the coefficient of static friction between the road and the tires is 0.102. Find the minimum stopping distance (in m). m == (b) When the road is dry, H, = 0.598. Find the minimum stopping distance (in m). m

A person of mass m= 80 kg pushes a fridge of mass M = 140 kg across a floor with a constant velocity in the +x hat direction. the interface between the floor and the fridge has coefficients of friction μs = 0.75 and μk= 0.35    What is the force exerted by the fridge on the person? F fridge --> person?

You push downward on a trunk at an angle 25° below the horizontal with a force of  750N If the trunk is on a flat surface and the coefficient of static friction between the surface and the trunk is 0.61, what is the most massive trunk you will be able to move?     93 kg     81 kg     112 kg     73 kg