Afive-milliwatt laser, emitting light with wavelength 690 nm is turned on for 20 seconds. we will approximate the beam as a cylinder of area 2.5 mm2 calculate the following beam quantities: a. length b. volume c. intensity d. energy e. energy density f. rms electric field g. rms magnetic field h. the number of photons (h 6.63 x 10-34 joules seconds.

Aperson stands on a platform, initially at rest, that can rotate freely without friction. the moment of inertia of the person plus the platform is ip. the person holds a spinning bicycle wheel with its axis horizontal. the wheel has moment of inertia iw and angular velocity ωw. take the ωw direction counterclockwise when viewed from above. part a what will be the angular velocity ωp of the platform if the person moves the axis of the wheel so that it points vertically upward?

Which car has the most kinetic energy? a. a car of mass 1000 kg with a speed of 3 m/s b. a car of mass 2000 kg with speed 7 m/s c. a car of mass 1000 kg with speed 7 m/s d. a car of mass 2000 kg with speed 3 m/s

What is the measure of a change in an objects velocity?