When the magnet falls toward the copper block, the changing flux in the copper creates eddy currents that oppose the change in flux. the resulting braking force between the magnet and the copper block always opposes the motion of the magnet, slowing it as it falls. the rate of the fall produces a rate of flux change sufficient to produce a current that provides the braking force. if the copper is cooled with liquid nitrogen, the resistivity of the copper drops dramatically. how will this affect the speed at which the magnet falls toward the copper? a) the magnet will fall at the same speed. b) the magnet will fall more rapidly. c) the magnet will fall more slowly.

Askydiver weighing 140 lb (including equipment) falls vertically downward from an altitude of 19,000 ft and opens the parachute after 18 s of free fall. assume that the force of air resistance, which is directed opposite to the velocity, is of magnitude 0.55|v| when the parachute is closed and is of magnitude 14|v| when the parachute is open, where the velocity v is measured in ft/s. assume that acceleration due to gravity has magnitude 32 ft/s/s; remember that weight is the product of mass and gravitational acceleration. (a) find the speed of the skydiver when the parachute opens. (b) find the distance fallen before the parachute opens. (c) what is the limiting velocity vl after the parachute opens? (d) determine how long the sky diver is in the air after the parachute opens. (e) plot the graph of velocity versus time from the beginning of the fall until the skydiver reaches the ground.

A250-n box is at rest on a frictionless horizotal floor. then a person shoves the box with a non-zero force of magnitude p. which statement best describes the relationship betweeen p and the motion of the box after it was shoved? -the box will not move when p< 250n but otherwise will accelerate at a constant rate that is directly proportional to p - the box will begin moving at a speed that is directly proportional to p, then will gradually slow to a halt -the box will move with constant velocity at a speed that is directly proportional to p -box will accelerate across the floor at a constant rate that is directly proportional to p

If angle "a" is 25°, angle "b" is: a) equal to angle c b) less than angle c c) greater than angle c