Lv 2333 points

• ### You push your physics book 1.50 m along a horizontal tabletop with a horizontal push of 2.40 N while opposing force of friction is 0.600 N.?

How much work does each of the following forces do on the book: (a) your 2.40-N push, (b) the friction force, and (c) gravity? (e) What is the net work done on the book?

• ### A nonzero net force acts on an object. Is it possible for any of the following quantities to be constant:?

(a) the particle’s speed; (b) the particle’s velocity; (c) the particle’s kinetic energy?

• ### You are holding a briefcase by the handle, with your arm straight down by your side.?

Does the force your hand exerts do work on the briefcase when (a) you walk at a constant speed on a horizontal floor and (b) you ride in an escalator from the first to second floor of a building? Explain.

• ### A net force acts on an object and accelerates it from rest to a speed V1. In doing so, the force does an amount of work W1.?

By what factor must the work done on the object be increased to produce three times the final speed, with the object again starting from rest?

• ### If there is a net nonzero force on a moving object, is it possible for the total work done on the object to be zero?

Explain. If the total work is negative, can its magnitude be larger than the initial kinetic energy of the object? Explain.

• ### For a constant force in the direction of the displacement, how can twice the work be done by a force of half the magnitude? ?

Physics2 months ago

• ### A/c to Newton’s Third law, the javelin exerts as much force on the athlete as the athlete exerts on the javelin.?

Would it be correct to say that javelin does work on the athlete?

Other - Sports2 months ago
• ### A block with mass of 5.00 kg is attached to a horizontal spring with spring constant k = 4.00 × 102 N/m. ?

The surface the block rests upon is frictionless. If the block is pulled out to xi = 0.0500 m and released, (a) find the speed of the block at the equilibrium point, (b) find the speed when x = 0.0250 m, and (c) repeat part (a) if friction acts on the block, with coefficient µk = 0.150.

Physics2 months ago
• ### A skier starts from rest at the top of a frictionless incline of height 20.0 m.?

At the bottom of the incline, the skier encounters a horizontal surface where the coefficient of kinetic friction between skis and snow is 0.210. (a) Find the skier’s speed at the bottom. (b) How far does the skier travel on the horizontal surface before coming to rest?

• ### A 2000-kg elevator with broken cables in a test rig is falling at when it contacts a cushioning spring at the bottom of the shaft.?

The spring is intended to stop the elevator, compressing 2.00 m as it does so. During the motion a safety clamp applies a constant 17,000-N frictional force to the

elevator. What is the necessary force constant k for the spring?

• ### Suppose a glider of mass 0.200 kg is initially at rest at x = 0, with the spring un-stretched.  ?

You then apply a constant force in +x-direction with magnitude 0.610 N to the glider. What is the glider’s velocity when it is moved to x = 0.100 m? where force constant of spring is 5.00 N/m.

Physics2 months ago
• ### Suppose your hand moves up 0.50 m while you are throwing the ball, which leaves your hand with an upward velocity of 20.0 m/s.?

Ignore air resistance. (a) Assuming that your hand exerts constant upward force on the ball, find the magnitude of the force, (b) Find the speed of the ball at a point 15.0 m above the point where it leaves your hand.

• ### A force parallel to the x-axis acts on a particle moving along the x-axis.?

This force produces potential energy given by U(x) = α x 4, where α = 1.20 J/m4. What is the force (magnitude and direction) when the particle is at x = -0.800 m?

• ### In one day, a 75-kg mountain climber ascends from the 1500-m level on a vertical cliff to the top at 2400 m. ?

The next day, she descends from the top to the base of the cliff, which is at an elevation of 1350 m. What is her change in gravitational potential energy (a) on the first day and (b) on the second day?

Physics2 months ago

• ### A box slides down a ramp and work is done on the box by the forces of gravity and friction.?

Can the work of each of these forces be expressed in terms of the change in a potential-energy function? For each force explain why or why not.

Physics2 months ago
• ### A woman bounces on a trampoline, going a little higher with each bounce. Explain how she increases the total mechanical energy?

Physics2 months ago
• ### A ball is released from rest from the roof of a building and falls to the ground.?

Its fall is observed by a student on the roof of the building, who uses coordinates with origin at the roof, and by a student on the ground, who uses coordinates with origin at the ground.

Do the two students assign the same or different values to the initial gravitational potential energy, the final gravitational potential energy, the change in gravitational potential energy, and the kinetic energy of the ball just before it strikes the ground? Explain.

Physics2 months ago