Two small spheres spaced 20.0 cm apart have equal charge. How many excess electrons must be present on each sphere if the magnitude of the force of repulsion between them is 4.57 x 10-21 N?

A. 562

B. 9.14 * 10^3

C. 1.01 * 10^6

D. 891

Eight grams of water changes from liquid to vapor at a pressure of one atmosphere. In the process, the volume changes from 0.8 cm³ to 674 cm³. The latent heat of vaporization of water is 2.26 * 10⁶ J/kg. Find the work done. Answer in units of J.

Change of state that occurs when hailstones form

Are the objects described here in static equilibrium, dynamic equilibrium, or not in equilibrium at all? a. A girder is lifted at constant speed by a crane. b. A girder is lowered by a crane. It is slowing down. c.

10. Provide the time dilation equation found in Section 15.4 of the text. Explain each step of the derivation.

A ball is dropped from a height of 20 meters. At what height does the ball have a velocity of 10 meters/second?

An electron is moving at a speed of 4.8 * 10 6 m/s at an angle of 30.0° with respect to a uniform magnetic field of 9.2 * 10 - 4 T. What is the radius of the resulting helical path? (me = 9.11 * 10 - 31 kg, qe = 1.60 * 10 - 19 C)

Which transfer of energy occurs mainly through the process of convection?

The statement, "All basketball players are tall" is a stereotype.

Lonnie pitches a baseball of mass 0.20 kg. The ball arrives at home plate with a speed of 40 m/s and is batted straight back to Lonnie with a return speed of 60 m/s. If the bat is in contact with the ball for 0.

7. What type of mineral can scratch glass, but cannot scratch steel? A. Gypsum B. Diamond C. Feldspar D. Fluorite