Which statement best describes the energy changes that occur while a child is riding on a sled down a steep, snow-covered hill?

a)
kinetic energy decreases and potential energy increases.

b)
kinetic energy increases and potential energy decreases.

c)
both potential and kinetic energy decrease.

d)
both potential and kinetic energy increase

Which type of wave can travel without a medium

When using the scientist method, which step comes last?

In the middle of the night you are standing a horizontal distance of 14.0 m from the high fence that surrounds the estate of your rich uncle. the top of the fence is 5.00 m above the ground. you have taped an important message to a rock that you want to throw over the fence. the ground is level, and the width of the fence is small enough to be ignored. you throw the rock from a height of 1.60 m above the ground and at an angle of 54.0 degrees above the horizontal. part a part complete what minimum initial speed must the rock have as it leaves your hand to clear the top of the fence? express your answer with the appropriate units. part b for the initial velocity calculated in the previous part, what horizontal distance beyond the fence will the rock land on the ground?