The power rating of a vacuum cleaner is 0.8 kilowatts. If you use the vacuum cleaner for 2.5 hours, how much energy does it use?

A submerged submarine alters its buoyancy so that it initially accelerates upward at 0.325 m/s^2. What is the submarine's average density at this time? (Hint: the density of sea water is 1.025x10^3 kg/m^3.)

What is heat and what is its effect on objects

The loss of an electron from a neutral helium atom results in

A boat crosses a 200m wide river at 3m/s, north relative to water. The river flows at 1m/s as shown. What is the velocity of the boat as observed by a stationary observer on the river back from the boat departed?

If the pitch of the sound coming out from a speaker increases, which is true about the sound wave?

What holds the atoms together in a covalent bond

The sun is the centermost star of our solar system. a. True b. False

When an electron moves from a lower to a higher energy level

Which of the following is all matter made of? A. Hot particles B. Cold particles C. Constantly moving particles D. Nonmoving particles

Which of the following has longest wavelength, a) blue light b) red light c) x-rays d) gamma rays?