A popular swinging-balls apparatus (Newton’s cradle) consists of a series of identical elastic balls suspended by strings so they barely touch each other. When two balls are pulled away from one end and released, they strike the row of balls and two balls pop out from the other end. If instead, one ball popped out with twice the speed, this would violate the conservation of

Just after a big fish swallows a small fish, the momentum of the two-fish system is

A push on a 1-kg brick accelerates the brick. Neglecting friction, to equally accelerate a 10-kg brick requires the force to be

Each of us weighs slightly less inside the ground floor of a skyscraper than we do on the ground away from the skyscraper because the

If an object falls with constant acceleration, the velocity of the object must

A softball player determines her pitching speed by throwing a ball horizontally from an elevation of 5 m above the ground. The ball lands 20 m downrange. What is her pitching speed?

A hunter aims a rifle at an angle of 10° above the horizontal. The hunter fires a bullet while simultaneously dropping another bullet from the side of the rifle. The bullet to hit the ground first is

A 1-kg chunk of putty moving at 1 m/s collides and sticks to a 5-kg bowling ball initially at rest. The bowling ball and putty move with a momentum of

If the mass of an object does not change, a constant net force on the object produces constant

A 0.5-kg blob of clay moving at 2.0 m/s slams into a 4.0-kg blob of clay at rest. The speed of the two blobs stuck together after colliding is about