Piles of snow on slippery roofs can become dangerous projectiles as they melt. Consider a chunk of snow at the ridge of a roof with a slope of 34°. (a) What is the minimum value of the coefficient of static friction that will keep the snow from sliding down? (b) As the snow begins to melt, the coefficient of static friction decreases and the snow finally slips. Assuming that the distance from the chunk to the edge of the roof is 4.0 m and the coefficient of kinetic friction is 0.10, calculate the speed of the snow chunk when it slides off the roof. (c) If the roof edge is 10.0 m above ground, estimate the speed of the snow when it hits the ground.

The objective of curling, an Olympic discipline, is to throw stones at houses. The stone is a 18 kg block of granite that slides on the carefully prepared ice with a very low coefficient of kinetic friction, μk = 0.0178. With a curling broom the players can increase the friction to get as close as possible to the house, the target pattern embedded in the ice. Frequently an oncoming stone will bump a stone from a previous throw by the competing team. A stone reaches the house with a velocity of 1.2 m/s after traveling the 38 m length of the curling sheet. How fast the stone was going when it was released? The stone did not hit any other stones.

A cougar bites a llama of mass m and drags it across some rough horizontal ground. The cougar applies a horizontal force of magnitude F, and the llama is dragged at a constant velocity. The coefficient of kinetic friction is μk. While the cougar applies the force F, the magnitude of the kinetic friction force, fk , on the llama obeys: a)F > µk m g > fk b)F = fk = µk m gc)F = fk  < µk m gd)cannot answer, not enough information givene) F > fk = µk m g

A truck is traveling at 14.7 m/s down a hill when the brakes on all four wheels lock. The hill makes an angle of 19 ° with respect to the horizontal. The coefficient of kinetic friction between the tires and the road is 0.789. How far, in meters, does the truck skid before coming to a stop?

A truck is traveling at 10.0 m/s down a hill when the brakes on all four wheels lock. The hill makes an angle of 11 ° with respect to the horizontal. The coefficient of kinetic friction between the tires and the road is 0.933. How far, in meters,  does the truck skid before coming to a stop?

Two crates of fruit  are released from the top of a ramp inclined at 30 degrees from the horizontal and 4.5 meter long. The two crates consist of  an apple crate of mass 20 kg that is placed in front of a watermelon crate of mass 80 kg.  The apple crate has a coefficient of friction of 0.20 while the watermelon crate has a coefficient of friction of 0.15. How long does it take the apple crate to reach the bottom of the incline if it needs to travel a distance of 4.5 meters?

a rock climber on a rock slab. The coefficient of kinetic friction between the climber's rock climbing shoes and the rock is 0.70.  If the climber slide down the rock starting from rest, the amount of time it will take the climber to slide to the edge of the rock slab is?  distance=16.4 m and theta is 68 degrees.

A roller-coaster car is towed up an incline at a steady speed of 0.500 m/s by a chain parallel to the surface of the incline. The slope is 3.00%, which means that the elevation increases by 3.00 m for every 100.0 m of horizontal distance. The mass of the roller-coaster car is 594 kg. Ignoring friction, what is the magnitude of the force exerted on the car by the chain?

An ice hockey puck is sliding over a frictionless horizontal surface with a constant velocity of vo = 10.2 m/s. Find the velocity of the puck after it passes a rough area of length L 6 m and with the kinetic friction coefficient u = 0.33 as shown below. Hint: the mass of the puck is not needed, you can either calculate everything per unit of mass or, if it helps, take m 160 grams. %3D %3D %3D %3D m Vo L The steps to follow: (1) find the initial KE of the puck; (2) find the work done by the friction force (should be negative); (3) find the final kinetic energy as KE; = KE; + W, meaning that some of the initial kinetic energy is lost due to the work done by friction; (4) from the final KE find the final speed. The final speed of the puck, Vf =7.28 X Units m/s %3D If the initial speed of the puck is not high enough the puck will get stuck in the rough area. At what minimal initial speed should the puck move to barely make it through the rough area? The minimal initial velocity, Vmin =…

An engineer is working on determining the speed limit for a curved stretch of road. She knows the coefficient of friction between the wheels and the road is 0.75 when the road is dry and 0.4 when the road is wet. She also knows that the mass of the vehicle does not matter, but completes her calculations for a 700kg car. In order to set a speed limit that is safe under any conditions, should she perform her calculations with the coefficient of friction for wet or dry pavement? wet Answer the following questions for the case when the car is traveling at the maximum speed with the road conditions selected above. In this case, what is the car's centripetal acceleration? m/s² In this case, what is the car's speed? m/s mph Could vehicles, obeying a speed limit of 75mph, navigate the curve in both wet and dry conditions? yes Reference 1 2 350m 3 4 5 6 7