Which of the following objects is in dynamic equilibrium?

a. a car driving in a straight line at 20m/s

b. a book sitting on a table without moving

c. a boy jumping off a diving board into a pool

d. a motorcycle going in a circle at a constant speed

What is the acceleration of a spaceship that is initially at rest and then speeds up to 220 m/s in 20 seconds

Which are true about beta reactions? there will be more than one answer. a. it has no change b. it doesn't change the mass of the number c. it has a mass of 0.0005 atoms d. it causes transmutation.

Light from two different sources are incident upon the same side of a polarizing filter. light from one source is polarized with total intensity ip, while light from the other source is unpolarized with total intensity iu. as you rotate the polarizing filter through 360 degrees, the intensity of the transmitted light on the other side varies by a factor of 9. what is the relative intensity of the initial polarized source to the unpolarized source, or ip/iu?