For conduction to occur,
a. dark objects are required to absorb energy.
b. substances must be in contact with each other.
c. hot and cold regions must flow within a substance.
d. heat must transfer from an area of less energy to more energy.

What type of electromagnetic wave is used in security pens? a. x-rays c. microwaves b. visible light d. ultraviolet radiation select the best answer from the choices provided

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?

Current from a charged capacitor lights a bulb. as time goes on the brightness of the