A 75kg refrigerator is located on the 70th floor of a skyscraper (300m above ground). What is the potential energy of the refrigerator?

A ball with a mass of 500 g is thrown directly upward by a boy standing over a 5 m hole in the ground. The ball leaves the boys hand at a height of 1 m above the ground and with a speed of 10 m/s. What is the total mechanical energy of the ball when it hits the bottom of the hole? Take ground level to be the zero of gravitational potential energy. Assume air resistance is negligible.

A 23 N rock is dropped from a height of 11.5 m, and the velocity right before hitting the ground is 13.50 m/s. What is the work done by the air friction?

On a playground slide, a child has potential energy PE = 450.0 J at the top of the slide. Thechild’s mass is 25.0 kg. (For simplicity, take the value of g to be 10.0 m/s2 in this problem.) When the child slides down to the bottom of the slide, her KE = 300.0 J. a) What was the height of the slide?b) How much was the work done by friction?c) How fast was the child moving when she reached the middle of the slide? (Assume that thework done by friction is half of what you get in (b). Note that the PE2 is not zero this time.)

A cable car with a mass of 5200-kg in Los Angeles (CA) is pulled a distance of 360 m along a cable up a hill inclined at 12° from the horizontal. The change in the potential energy of the car is 3.8 x10^6 3.9 x10^5 1.8 x10^7 O2.3 x10^7

A roller coaster car with mass m and initial velocity v is at height h above the ground. Calculate the potential energy, kinetic energy and velocity for the following values:   h(m) m(kg) v(m/s) 1.00E+02 5.00E+02 0.00E+00

A 4 kg block is initially sliding up a 30° incline at 6 m/s. It slides 3 m along the surface before coming to rest.  Gravity did ____ J of work on the block during this segment of motion.   A 4 kg block is initially sliding up a 30° incline at 6 m/s. It slides 3 m along the surface before coming to rest.  Kinetic friction did ____ J of work on the block during this segment of motion.

A 7.80-g bullet moving at 590 m/s penetrates a tree trunk to a depth of 5.60 cm. (a) Use work and energy considerations to find the average frictional force that stops the bullet. N=(b) Assuming the frictional force is constant, determine how much time elapses between the moment the bullet enters the tree and the moment it stops moving. s=

A 0.23-kg stone is held 1.5 m above the top edge a water well and then dropped into it. The well has a depth of 5.3 m. (a) Taking y = 0 at the top edge of the well, what is the gravitational potential energy of the stone-Earth system before the stone is released? J (b) Taking y = 0 at the top edge of the well, what is the gravitational potential energy of the stone-Earth system when it reaches the bottom of the well? J (c) What is the change in gravitational potential energy of the system from release to reaching the bottom of the well? J