A child is playing on a hill with a cardboard box. The combined mass of child and box is ? = 120 kg. He climbs into box, which is initially at rest, at the top of the hill. The hill is inclined at an angle of 30 degrees with respect to the horizontal. The coefficients of static and kinetic friction between the box and the hill are mu s = 0.4 and mu k = 0.2. Consider that the child has climbed into the box, but it has not yet started moving. What is the magnitude of the friction force acting on the box? b. What is the magnitude of the net force acting on the box + child system?

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?

A child is playing on a hill with a cardboard box. The combined mass of child and box is ? = 120 kg. He climbs into box, which is initially at rest, at the top of the hill. The hill is inclined at an angle of 30 degrees with respect to the horizontal. The coefficients of static and kinetic friction between the box and the hill are mu s = 0.4 and mu k = 0.2. Consider that the box (with child inside) has begun to slide down the hill (you can assume that it has been given a brief push to get it started moving). What is the magnitude of the acceleration of the box?  b. If the hill is 4 m tall, what is the child’s speed when he reaches the bottom? c. At the bottom of the hill, the ground becomes level (horizontal), but the coefficients of friction do not change. How far does the child slide before he comes to a stop? Thank you in advance, it's a lengthy question and I really need help :)

Mary and her sister are playing with a cardboard box on the neighborhood hill. Mary climbs into the box, the total mass of the box with Mary in it is 115 kg. The box starts at rest at the beginning of the incline. The hill is at an incline of 28 degrees with respect to the horizontal.The static and kinectic friction between the box and hill is 0.4 and 0.2 respectively. Assume that Mary is now in the box, but has not started to move. a. What is the magnitude of the friction force acting on the box?b. What is the magnitude of the net force acting on the box and child system?c. Will the box slide down the hill, or stay at rest?

A sphere of mass 4.7 × 10-4 kg is suspended from a cord. A steady horizontal breeze pushes the sphere so that the cord makes a constant angle of 26° with the vertical. Find (a) the magnitude of that push and (b) the tension in the cord.

A book of mass 9 kg rests on a plank. You tilt one end of the plank and slowly increase the angle of the tilt. The coefficient of static friction between the book and the plank is 0.48. What is the maximum angle of tilt for which the book will remain stationary and not slide down the plank?

A 2.30 kg block is initially at rest on a horizontal surface. A horizontal force of magnitude 5.92 N and a vertical force are then applied to the block (see the figure). The coefficients of friction for the block and surface are us = 0.4 and Uk = 0.25. Determine the magnitude of the frictional force acting on the block if the magnitude of P is (a)7.00 N and (b)10.0 N. (The upward pull is insufficient to move the block vertically.) (a) Number i (b) Number i Units Units P € }

A constant force Fa pushes a 22.5-kg box across a rough horizontal surface. The magnitude of Fa is 185 N and the force is inclined at an angle of θ = 30.0° below the horizontal. The coefficient of kinetic friction between the box and the surface is μk = 0.500. What is the magnitude of the box's acceleration?

A 100 kg block is at rest on a flat floor with a coefficient of static friction 0.62. A horizontal force of 3.7 N is applied to the block, but it does not budge. What is the magnitude of the frictional force on the block applied?

A woman exerts a horizontal force of 145 N on a crate with a mass of 38.7kg. (a) If the crate doesn't move, what's the magnitude of the static friction force (in N)?   (b) What is the minimum possible value of the coefficient of static friction between the crate and the floor? (Assume the crate remains stationary.)