During a lunar eclipse, the earth lies directly between the moon and the sun. To an astronaut on the moon, this event is just like a solar eclipse with the earth obscuring the sun: however, the earth is large enough that instead of exactly obscuring the sun it appears 4 times wider. Use this information to estimate the diameter of the earth.

An observer that stands still as the electron moves by him, will observe

Awater-filled u-tube manometer is used to measure the pressure inside a tank that contains air. the water level in the u-tube on the side that connects to the tank is 5 ft above the base of the tank. the water level in the other side of the u-tube (which is open to the atmosphere) is 2 ft above the base. determine the pressure within the tank.

An athlete is holding 24 lb of weights at a height of 6 inches above the stack as shown. to lower the weights, she applies a constant force of 5 lb to the handle. determine the velocity of the weights immediately before they hit the stack.