Which will be attracted to (or repelled by) a magnet?
a. copper wire not carrying any current
b. an aluminum wire carrying current
c. a positively charged glass rod
d. an iron horseshoe
e. an electromagnet

To travel at constant speed, a car engine provides 24kw of useful power. the driving force on the car is 600n. at what speed does it travel?

Unpolarized light of intensity i_0=750w/m^2 is incident upon two polarizers. after passing through both polarizers the intensity is i_2=280w/m^2. (a) what is the intensity of the light after it passes through the first polarizer in w/m^2? (b) write an equation for the angle between the polarizers in terms of the initial (i_0) and final (i_2) intensities. (c) find the angle between the polarizers in degrees.

What is the coefficient of kinetic friction μk between the block and the tabletop?