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An object weighs 432 N on the surface of the Earth. The Earth has radius r. If the object is raised to a height of 3r above the Earth’s surface, what is its weight?

For a spacecraft going from the Earth toward the Sun, at what distance from the Earth will the gravitational forces due to the Sun and the Earth cancel? Earth’s mass: Me = 5.98 x 1024 kg the Sun’s mass: Ms = 1.99 x 1030 kg Earth-Sun distance: r = 1.50 x 1011 m

p2something.png An object side a distance d down and incline of height ∆y as shown.  If the coefficient of friction between the surface and the object is 0.250, determine the work done by friction. m = 5.00 kg, d = 9.00 m,  and ∆y = 3.00 m.

A worker pushes a 8.0 kg crate across a level surface with a force of 35.0 N directed at an angle of 25.0° downward from the horizontal. Determine the work done by gravity after the crate is pushed 12.0 m.

A car of mass 1750 kg accelerates from 0.00 m/s to 35.0 m/s.  What was the net work done on the car? 

p2something.png An object slides a distance d = 9.00 m down an incline of height ∆y = 3.00 m as shown.  Determine the speed of the object at the bottom of the incline if it starts from rest and the coefficient of kinetic friction between the object and the surface is 0.25.

The force on an electric charge in an electric field is F = qE where F is the force, q is the electric charge, and E is the electric field.  Determine the speed of a proton (charge = 1.6×10-19 C, mass = 1.67×10-27 kg) after it has been accelerated, from rest, a distance of 0.25 m though an electric field of 2.0×106 N/C. 

A spring of spring constant 800 N/m is used to launch a 15.0 g projectile vertically upward.  By how much must the spring be compressed in order for the projectile to reach a maximum height of 35.0 m?

A child sleds down a 3.5 m tall snowy hill.  Ignoring friction, determine the child’s speed at the bottom of the hill.

A 500 kg ore cart traveling at 12.0 m/s on a level track is stopped by a spring of spring constant 35,000 N/m mounted horizontally at the end of the track.  By how much does the spring compress in stopping the car?