You are pushing a sled in which your little sister is seated up a 28° slope (one that makes an angle of 28° with the horizontal). If the mass of the sled and girl is 40 kg, and the coefficient of kinetic friction between the sled and the surface is 0.100, with what magnitude of force do you need to push in order for the sled to move with constant velocity?

A lamp hangs vertically from a cord in a descending elevator that decelerates at 1.7 m/s2. (a) If the tension in the cord is 63 N, what is the lamp's mass? (b) What is the cord's tension when the elevator ascends with an upward acceleration of 1.7 m/s2?

A man wants to move a heavy wooden crate (82 kg) across a wooden floor.  However, since he is taller than the crate, he must pull it using a rope that makes an angle of 42 degrees with the horizontal.  He exerts a force of 312 N as he pulls.  What is the Normal Force exerted by the floor on the crate? What is the size of the Friction Force felt by the crate, if the crate moves at a constant speed in a straight line? Imagine that instead the floor is more slick, so that the crate feels a friction force half of what you calculated above.  What is the crate’s acceleration?

A 104 kg crate is sitting at the top of a ramp, which is inclined at an angle of 28 degrees with respect to the horizontal. What is the minimum value for the coefficient of static friction that allows the box to stay at rest at the top of the ramp?

You are pulling your luggage in an air port for an international flight. You know not to pack too much else they charge you extra fees so you weighted your luggage at home to be 22.0 kg. You exert a pull of 46 N in magnitude and at 24 degrees above the horizontal to ensure you can walk at a constant speed on the carpeted floor. What is the coefficient of friction between the caster wheels and the carpet?

Consider a wooden ramp angled 31.7 degrees above horizontal. If a 20.3-kg wooden block is given a strong shove up the ramp so that it has an initial velocity of 22.9 m/s, how long (in seconds) will it take the block to reach its maximum height (before it starts sliding down)? The coefficient of kinetic friction between the block and the ramp is 0.402.

The figure below shows a box with a mass of m= 3.90 kg on a ramp inclined at an angle of 35.0°. The coefficient of static friction between the box and the ramp is 0.250. Find the minimum magnitude of the force F (in N), applied to the box in a direction perpendicular to the ramp, that will prevent the box from sliding down the ramp. N m 35.0°

A tug-of-war match happens between Team Blue and Team Red. Each of Team Blue’s members has an average mass of 76 kg and exerts an average force of 1225 N horizontally. Each of Team Red’s members has an average mass of 78 kg and exerts an average force of 1275 N horizontally. What is the tension in the section of rope between the teams?

You are pulling a 72-kg box at a constant speed of 7.4 m/s. If you're pulling the rope with a force of 300 N at an angle of 37° measured above the horizontal, what is the coefficient of friction between the box and the ground?

A large cube (mass = M) being accelerated across a horizontal frictionless surface by a horizontal force . A small cube (mass = m) is in contact with the front surface of the large cube and will slide downward unless is sufficiently large. The coefficient of static friction between the cubes is u. What is the smallest magnitude that F can have in order to keep the small cube from sliding downward?