"Rocket Man" has a propulsion unit strapped to his back. He starts from rest on the ground, fires the unit, and accelerates straight upward. At a height of 16 m, his speed is 5.0 m/s. His mass, including the propulsion unit, has the approximately constant value of 136 kg. Find the work done by the force generated by the propulsion unit.

Two blocks are connected by a very light string passing over a massless and frictionless pulley. Traveling at constant speed, the 20.0 N block moves 75.0 cm to the right and the 12.0 N 20.0 N 12.0 block moves 75.0 cm downward.  How much work is done on the 20.0 N block by (i) the tension in the string, (ii) friction, and (iii) the normal force? (b) Find the total work done on each block.

An asteroid is moving along a straight line. A force acts along the displacement of the asteroid and slows it down. The asteroid has a mass of 4.7× 104 kg, and the force causes its speed to change from 7300 to 5300m/s. (a) What is the work done by the force? (b) If the asteroid slows down over a distance of 1.6× 106 m determine the magnitude of the force.

A box of mass 12.0 kg begins at rest, and is accelerated at a rate of 1.5 m/s2 by a force F for 10.0 seconds. What is the work done by the force F?

Your answer is partially correct. The (non-conservative) force propelling a 1.10 x 10-kg car up a mountain road does 7.50 x 106 J of work on the car. The car starts from rest at sea level and has a speed of 26.0 m/s at an altitude of 2.20 x 102 m above sea level. Obtain the work done on the car by the combined forces of friction and air resistance, both of which are non-conservative forces. Number 4757000 Units eTextbook and Media Hint Save for Later Attempts: 4 of 10 used Submit Answer h 77% 74°F Mostly 画 Home End Insert F5 F6 F7 F8 De F9 F10 F1 F12 % Bac 7 8 R Y U | G H J K L VBN M

An asteroid is moving along a straight line. A force acts along the displacement of the asteroid and slows it down. The asteroid has a mass of 4.2x 104 kg, and the force causes its speed to change from 7500 to 5000m/s. (a) What is the work done by the force? (b) If the asteroid slows down over a distance of 1.7x 106 m determine the magnitude of the force. (a) Work= (b) F= i i

An asteroid is moving along a straight line. A force acts along the displacement of the asteroid and slows it down. The asteroid has a mass of 4.8× 104 kg, and the force causes its speed to change from 7100 to 4900m/s. (a) What is the work done by the force? (b) If the asteroid slows down over a distance of 2× 106 m determine the magnitude of the force.

A water-skier is being pulled by a tow rope attached to a boat. As the driver pushes the throttle forward, the skier accelerates. A 61.2-kg water-skier has an initial speed of 5.1 m/s. Later, the speed increases to 12.1 m/s. Determine the work done by the net external force acting on the skier.

A hockey puck of mass 0.26 kg is sliding along a slippery frozen lake, with an initial speed of 64 m/s. The coefficient of friction between the ice and the puck is eventually causes the puck to slide to a stop. Find the work done by friction. J = 0.031. Friction

A helicopter lifts a 85 kg astronaut 13 m vertically from the ocean by means of a cable. The acceleration of the astronaut is g/10. How much work is done on the astronaut by (a) the force from the helicopter and (b) the gravitational force on her? Just before she reaches the helicopter, what are her (c) kinetic energy and (d) speed?