The hot glowing surfaces of stars emit energy in the form of electromagnetic radiation. it is a good approximation to assume that the emissivity e is equal to 1 for these surfaces.

A cat is running at 24 m/s. It then accelerates at 7 m/s2. How long will it take the cat to reach a speed of 49 m/s?

A skier halfway between the top and bottom of a hill. Which statement best describes the skier?

The grid in a triode is kept negatively charged to prevent ... a. the variations in voltage from getting too large. b. electrons being repelled back to the cathode. c. electrons from escaping from the tube containing the triode. d.

Beta particles cannot penetrate very far into solids because they: 1. have low velocity 2. have negligible mass 3. have no mass 4. have no mass are confined to orbits

Which ions are most abundant in water?

Which is the best description of the acceleration of an object? an airplane changes elevation from 10,000 ft to 5,000 ft a cars velocity changes from 25 m/s to 20 m/s in 5 seconds a runner travels 100 m in one minute a remote-control car speeds up

What is the mechanical advantage of a machine that exerts a force of 160 N on an object when a person exerts a force of 20 N on the machine?

Suppose your hair grows at the rate of 1/55 inch per day. Find the rate at which it grows in nanometers per second. Because the distance between atoms in a molecule is on the order of 0.

A water skier is pulled behind a boat. When the skis push down on the water, what is the reaction force? A. The skier pulls back on the boat. B. Earth's gravity pulls down on the skis. C. The water pushes up on the skis. D. The boat pulls the skier.

Approximately how much electrical energy does a 5-W light bulb convert to radiant or thermal energy in one hour