Astudent is standing in an elevator that is
accelerating downward. the force that the
student exerts on the floor of the elevator must
be
(1) less than the weight of the student when at
rest
(2) greater than the weight of the student when
at rest
(3) less than the force of the floor on the student
(4) greater than the force of the floor on the
student

Aspring with a mass of 2 kg has a damping constant 14 kg/s. a force of 3.6 n is required to keep the spring stretched 0.3 m beyond its natural length. the spring is stretched 0.6 m beyond its natural length and then released. find the position of the mass at any time t. (assume that movement to the right is the positive x-direction and the spring is attached to a wall at the left end.)

Spend time observing or thinking about events that involve matter and energy. which events can you explain? which events can’t you explain?

Photoelectrons with a maximum speed of 6.50 x 107 m/s are ejected from a surface in the presence of light with a frequency of 6.75 x 1014hz. if the mass of an electron is 9.10 x 10-31 kg, calculate in joules the maximum kinetic energy of a single electron. 3.84 x 10-15 j 1.92 x 10-15 j 5.92 x 10-23 j 3.07 x 10-16 j