A lumberjack is trying to drag a small tree that he cut down. If the static coefficient of friction of the tree on the ground is 0.5 and the tree weighs 430 N, what is the minimum amount of horizontal force that he will need to apply so that the tree will start moving?

A car (m = 1600 kg) is parked on a road that rises 12° above the horizontal. What are the magnitudes of (a) the normal force and (b)the static frictional force that the ground exerts on the tires?

A car (m = 1630 kg) is parked on a road that rises 11° above the horizontal. What are the magnitudes of (a) the normal force and (b) the static frictional force that the ground exerts on the tires?

Sammy is doing a strength testing session on the turf in preparation for the upcoming basketball season.  Sammy's mass is 55 kg and she is trying to push a 105 kg sled across the artificial turf outside on Raymond Field.  The coefficient of static friction between the sled and the turf is 0.3.  If Sammy pushes only horizontally against the sled, how much force must she push with to just initiate movement of the sled? (hint: be sure to follow the steps outlined for free body diagrams, including drawing the free body diagram with all forces, force equations in the X and Y direction, and a coordinate system)

A block with a mass of 4.83 kg is at rest on an inclined surface. The surface makes an angle of  27.9° relative to horizontal. The coefficients of static and kinetic friction are 0.740 and 0.380 respectively. The block remains at rest. What is the magnitude of the frictional force that acts on the block?

A heavy sled is being pulled by two people, as shown in the figure. The coefficient of static friction between the sled and the ground is µs = 0.603, and the kinetic friction coefficient is = 0.403. The combined mass of the sled and its load is m = 336 kg. The ropes are separated by an angle o = 25.0°, and they make an angle 0 = 31.1° with the horizontal. Assuming both ropes pull equally hard, what is the minimum rope tension required to get the sled moving? minimum rope tension: N If this rope tension is maintained after the sled starts moving, what is the sled's acceleration? acceleration: m/s2

A 16 kg block of steel is at rest on a horizontal table. The coefficient of static friction between block and table is 0.54. (a) What is the magnitude of the horizontal force that will put the block on the verge of moving? 84.7 N (b) What is the magnitude of a force acting upward 60° from the horizontal that will put the block on the verge of moving? X N (c) If the force acts down at 60° from the horizontal, how large can its magnitude be without causing the block to move? N

A worker pulls a 15-kg crate in a straight line on a level surface by imparting a horizontal tension of 80 N to the free end of a cable whose other end is attached to the crate. If the coefficient of static friction is 0.40, what is the acceleration of the crate?

An early submersible craft for deep-sea exploration was raised and lowered by a cable from a ship. When the craft was stationary, the tension in the cable was 6500 N. When the craft was lowered or raised at a steady rate, the motion through the water added an 1800 N drag force.  What is the weight of the rider?

You are given the job of moving a refrigerator with a mass of 1.8 x 102 kg across a horizontal floor. The coefficient of static friction between the refrigerator and the floor is 0.45. Calculate the magnitude of the minimum force that is required just to set the refrigerator into motion.