In the figure the coefficients of static and kinetic friction between the crate and the incline are Hs = 0.6 and Hk 0.5 respectively. The 11.8 kg box is given a small push causing it to slide down the incline. Find the frictional (in Newtons) force while the mass is sliding if a = 28.3 °. %3D

5. (a) The weight of the block in the diagram is 54 N. The coefficient of static friction between the block and the vertical wall is 0.570. What minimum magnitude of the force F is required to prevent the block from sliding down the wall? (Note that the static frictional force is directed upward, parallel to the wall) Block F40.0° Vertical wall (b) A 104 kg baseball player slides into second base. The coefficient of kinetic friction between the player and the ground is μ = 0.651. (i) What is the magnitude of the frictional force? (ii) If the player comes to rest after 1.13 s, what is his initial speed?

25 & 26

4. You are pushing horizontally with a 300 N force on a box that is on an inclined plane as shown. The mass of the box is 30 kg and the incline is at a 25 degree angle off the Fapplied horizontal. The coefficient of kinetic friction between the box and the incline is 0.3, and the coefficient of static friction i 0.4. Assuming the box was at rest at t=0 when the force is initially applied, is the box moving up the ramp, down the ramp, or is it at rest after the force has been applied? 25⁰