15. You are unloading a 35 kg fridge from the back of a truck. It slips out of your hand and rolls down the ramp that is 1.2 m tall and 3.1 m long. The force of friction on the fridge is 45 N.
a.
How much thermal energy is produced by the time the fridge gets to the bottom of the ramp?
b. How fast will the fridge be moving at the bottom of the ramp?
C. If you need to push an identical fridge back up the ramp in 15 s, how much power would you need
to generate?

How have the competing explanations' experiments on atoms affected the development of the atomic model?

Askydiver weighing 140 lb (including equipment) falls vertically downward from an altitude of 19,000 ft and opens the parachute after 18 s of free fall. assume that the force of air resistance, which is directed opposite to the velocity, is of magnitude 0.55|v| when the parachute is closed and is of magnitude 14|v| when the parachute is open, where the velocity v is measured in ft/s. assume that acceleration due to gravity has magnitude 32 ft/s/s; remember that weight is the product of mass and gravitational acceleration. (a) find the speed of the skydiver when the parachute opens. (b) find the distance fallen before the parachute opens. (c) what is the limiting velocity vl after the parachute opens? (d) determine how long the sky diver is in the air after the parachute opens. (e) plot the graph of velocity versus time from the beginning of the fall until the skydiver reaches the ground.

What do elements in a family tend to share. a.) similar periods b.) similar groups c.) similar atomic symbols d.) similar chemical properties and characteristics