Hydroelectric power uses: wind water coal the sun

You toss an apple from 5 m tree. The apple hits your head on the ground that is 7 m away from the tree. How fast did you throw the apple?

A rock is thrown down with an initial speed of 25.3 m/s from a bridge to the water below. It takes 2.29 s for the rock to hit the water. How high is the bridge above the water in meters?

If the magnetic field strength in the spectrometer is increased, will the spacing between where the 235u and 238u ions strike increase, decrease, or stay the same?

A sprinkler sprays water out of a hose with a velocity of 6.3 m/s. if the sprinkler is aimed 25° above the ground, at what distance from the sprinkler does the water hit the ground? ignore air resistance and use 9.

How are mechanical weathering and chemical weathering similar

Janice has just measured the density of an object. Which value is possible? (Density: D = )

Based on how the book describes a heat pump in sec 16.3 how does a heat pump prove law of conservation of energy

When a gas in a container is squeezed to half its volume, its density?

A ballet student with her arms and a leg extended spins with an initial rotational speed of 0.90rev/s. As she draws her arms and leg in toward her body, her rotational inertia becomes 0.80 kg⋅m2 and her rotational velocity is 4.1rev/s.

The power rating of a vacuum cleaner is 0.8 kilowatts. If you use the vacuum cleaner for 2.5 hours, how much energy does it use?