5. A force of 250 N is applied to the right (horizontally) on a 50-kg block that rests on a horizontal surface. The coefficient of static and kinetic friction are 0.50 and 0.35, respectively. Which of the following statements is correct? A) The block remains at rest. B) The block moves and continues to move at constant velocity. C) The block accelerates to the right. D) The block does not move until is increased to greater than 490 N. E) No conclusions can be drawn concerning the movement of the block from the information given.

A 3.00-kg block starts from rest at the top of a 27.5° incline and slides 2.00 m down the incline in 1.30 s. (a) Find the acceleration of the block. m/s² (b) Find the coefficient of kinetic friction between the block and the incline. (c) Find the frictional force acting on the block. N (d) Find the speed of the block after it has slid 2.00 m. m/s

2) Veronica is working in a shoe test lab measuring the coefficient of friction for tennis shoes on a variety of surfaces. The shoes are pushed against the surface with a force of 400 N, and a sample of the surface material is then pulled out from under the shoe by a machine. The machine pulls with a force of 300 N before the material begins to slide. When the material is sliding, the machine has to pull with a force of only 200 N to keep the material moving. a. What is the coefficient of static friction between the shoe and the material? b. What is the coefficient of dynamic friction between the shoe and the material?

You are helping your friend move a new refrigerator into his kitchen. You apply a horizontal force of 263 N in the negative x direction to try and move the 53 kg refrigerator. The coefficient of static friction is 0.70. (a) How much static frictional force does the floor exert on the refrigerator? Give both magnitude (in N) and direction. magnitude N direction -Select--- ✓ (b) What maximum force (in N) do you need to apply before the refrigerator starts to move? N

A 620 kg car pulling a 495 kg trailer accelerates forward at a rate of 2.20 m/s2. Assume frictional forces on the trailer are negligible. Ignore air drag.   (c) What is the force (in N) exerted by the trailer on the car?   Magnitude: Direction: (forward or backward)

10. To meet a U.S. Postal Service requirement, employees' footwear must have a coefficient of static friction of 0.5 or more on a specified tile surface. A typical athletic shoe has a coefficient of static friction of 0.800. In an emergency, what is the minimum time interval in which a person starting from rest can move 3.00 m on the tile surface if she is wearing (a) footwear meeting the Postal Service minimum and (b) a typical athletic shoe? Answers: a) 1.11 s b) 0.875 s