a flat,horizo

A person pushes a 0.20 kg lunch tray across a table, and it slows down as it slides because of friction. The coefficients of friction between the tray and the table are µs = 0.15 and µk = 0.11. What would the acceleration of the tray be?

A 140 kg wooden crate resting on a wood floor. The coefficients of stattic and kinetic friction here are μs =0.5 and μk=0.3. WHat maximum force, in newtons, can you exert horizontally on the crate without moving it? If you continue to extert this force once the crate starts to slip, what will its accelertation be in m/s2?

A 100-kg man stands in an elevator that starts to move from the fifth floor towards the first floor. In the initial portion of the trip, the elevator has an acceleration of 1.5 m/s2 . What is the force exerted by the floor on the man?

You are designing a high-speed elevator for a new skyscraper. The elevator will have a mass limit of 2400 kg (including passengers). For passenger comfort, you choose the maximum ascent speed to be 18.0 m/s, the maximum descent speed to be 10.0 m/s, and the maximum acceleration magnitude to be 5.00 m/s2. Ignore friction. What is the maximum upward force that the supporting cables exert on the elevator car?

A 30.7 kg girl and a 59.8 kg boy are on the surface of a frozen lake, 10.5 m apart. Using a rope, the girl exerts a horizontal 4.20 N force on the boy, pulling him toward her. Calculate the magnitude of the girl's acceleration.

A 34.8 kg child is sitting at the top of a slide, which is inclined at an angle of 55 degrees with respect to the horizontal. Someone gives the child a quick push to get them moving, after which they slide down the incline without any further assistance. The coefficient of kinetic friction between the child and the slide is μ s  = 0.44. What is the magnitude of the acceleration (in m/s2) of the child?

A 4 kg block is sliding down a vertical wall while being pushed by an external force as shown in the figure. What is the magnitude of the acceleration of the block (in m/s2) if the coefficient of kinetic friction between the wall and the block is uj, = 0.20 and the magnitude of the external force is 20 N? 4 kg 30 X 8.8

A contestant in a winter sports contest pulls a 47 kg brick of ice 25 degrees in the positive horizontal direction with a rope over his shoulders over a frozen lake. Assume the coefficients of static and kinetic friction are µs=0.1 and µk=0.03. 1. Calculate the minimum force F he must exert to get the brick sliding in newtons.  2. What is its acceleration in m/s2 once it starts to move, if that force is maintained?