Chapter 4, Problem 95GP

Problem 1: Component in a Specified Direction. Determine the compo- nents of a 5 kN force F acting at point A, in the direction of a line from A to B. Given: A=(2,3,-2.1) m and B = (-2.5, 1.5, 2.2) m

Page 30 states: You push a file cabinet up a frictionless ramp tilted at 10°with horizontal. The file cabinet has a mass of 100 kg and you are pushing with a 700 N force in the direction up along the ramp. The file cabinet has initial speed of 2.0 m/s. It’s moved 8.0 m up along the ramp.

A 14 kg block measures 7 cm by 9 cm by 25 cm. When it slides on a 9 cm by 25 cm face, it moves with constant speed when pulled horizontally by a force whose magnitude is 17 N. How big a horizontal force must be applied to pull it with constant speed if it slides on a 7 cm by 25 cm face?

A person steps horizontally off the roof of a single-story house that is 3.1 m high. When his feet hit theground below, he bends his knees such that his torso decelerates over a distance of 0.65 m before coming to astop. If the mass of his torso is 50 kg, what is the average net force exerted on his torso over this distance?

Sally wants to hang up some decorations on the side of her house, so she props up a ladder of length L = 3m against a wall at an angle of θ = 50° with respect to the horizontal. The ground is somewhat icy, where the coefficient of static friction between the ground and the ladder’s feet is µ = 0.55; while the wall of her house can be considered frictionless. If Sally has a mass of 60kg and the ladder has a mass of 80kg, what is the max distance that she can climb up the length of the ladder without it slipping? You may assume the ground is perfectly flat, and the wall is perpendicular to the ground.

You are a member of an alpine rescue team and must get a box of supplies, with mass 2.30 kg , up an incline of constant slope angle 30.0 ∘ so that it reaches a stranded skier who is a vertical distance 2.50 m above the bottom of the incline. There is some friction present; the kinetic coefficient of friction is 6.00×10−2. Since you can't walk up the incline, you give the box a push that gives it an initial velocity; then the box slides up the incline, slowing down under the forces of friction and gravity. Take acceleration due to gravity to be 9.81 m/s2. Use the work-energy theorem to calculate the minimum speed v that you must give the box at the bottom of the incline so that it will reach the skier. Express your answer numerically, in meters per second.

As shown, a light string that does not stretch changes from horizontal to vertical as it passes over the edge of a table. The string connects m1, a 3.50-kg block originally at rest on the horizontal table at a height h = 1.20 m above the floor, to m2, a hanging 1.90-kg block originally a distance d = 0.900 m above the floor. Neither the surface of the table nor its edge exerts a force of kinetic friction. The blocks start to move from rest. The sliding block m1 is projected horizontally after reaching the edge of the table. The hanging block m2 stops without bouncing when it strikes the floor. Consider the two blocks plus the Earth as the system. (a) Find the speed at which m1 leaves the edge of the table. (b) Find the impact speed of m1 on the floor. (c) What is the shortest length of the string so that it does not go taut while m1 is in flight? (d) Is the energy of the system when it is released from rest equal to the energy of the system just before m1 strikes the ground? (e) Why or…

A light plane of mass 1000kg makes an emergency landing on a short runway. With its engine off, it lands on the runway at a speed of 40m⋅s-1 . A hook on the plane snags a cable attached to a 120kg sandbag and drags the sandbag along. If the coefficient of friction between the sandbag and the runway is µk = 0.4, and if the plane’s brakes give an additional retarding force of magnitude 1400N, how far does the plane go before it comes to a stop?

Consider the following force vectors: A =-3î + ĵ + 2k (N) B = 2î – ĵ – k (N) 1. Vectors Á, B , and C maintain a body in equilibrium. What is vector C (in unit vector form)? Answer 1: 2. Evaluate: Bx A - (B. A)