This is a force that acts over a distance, can not be seen, and causes like poles to repel and opposite poles to attract. What is this force?

A)

gravity

B)

friction

C)

magnetism

D)

air resistenace

What kind of wave is light?

An adventurous archeologist (m = 80.5 kg) tries to cross a river by swinging from a vine. The vine is 11.0 m long, and his speed at the bottom of the swing is 7.80 m/s. The archeologist doesn't know that the vine has a breaking strength of 1,000 N.

A father racing his son has 1/4 the kinetic energy of the son, who has 1/3 the mass of the father. The father speeds up by 1.2 m/s and then has the same kinetic energy as the son. What are the original speeds of (a) the father and (b) the son?

How is net force calculated when two forces act on an object in opposite directions?

The box moves at a constant speed. If the mass of the box is 4.0 kg, and it is pushed 2.2 m vertically upward, the coefficient of friction is 0.35, and the angle θ is 37°. What is the work done by the force, F? Use g = 10 m/s2.

How would the moon appear from earth if the moon did not rotate?

Block B has mass 4.00 kg and sits at rest on a horizontal, frictionless surface. Block A has mass 2.00 kg and sits at rest on top of block B. The coefficient of static friction between the two blocks is 0.400.

T=2π√ (l/g) is dimensionally correct

A penny falls from a windowsill which is 25.0 m above the sidewalk. How much time does a passerby on the sidewalk below have to move out of the way before the penny hits the ground?

Show that the Newton has the units of mass times acceleration.