1 Point
Liz and Jacqueline each hit a golf ball off the top of an ocean cliff. Liz's ball
has a horizontal velocity of 20 m/s and a vertical velocity of 1 m/s.
Jacqueline's ball has a horizontal velocity of 20 m/s and a vertical velocity of
2 m/s. Which of the following statements is true?
A. The two balls will stay in the air the same time, but Jacqueline's
will travel farther.
B. The two balls will stay in the air the same time, but Liz's will travel
farther.
O o o
C. Jacqueline's ball will stay in the air longer and travel farther.
W
D. Liz's ball will stay in the air longer and travel farther.
O
SUBMIT

In a thunderstorm, charge builds up on the water droplets or ice crystals in a cloud. thus, the charge can be considered to be distributed uniformly throughout the cloud. for the purposes of this problem, take the cloud to be a sphere of diameter 1.00 kilometer. the point of this problem is to estimate the maximum amount of charge that this cloud can contain, assuming that the charge builds up until the electric field at the surface of the cloud reaches the value at which the surrounding air breaks down. this breakdown means that the air becomes highly ionized, enabling it to conduct the charge from the cloud to the ground or another nearby cloud. the ionized air will then emit light due to the recombination of the electrons and atoms to form excited molecules that radiate light. in addition, the large current will heat up the air, resulting in its rapid expansion. these two phenomena account for the appearance of lightning and the sound of thunder. take the breakdown electric field of air to be eb=3.00ă—106n/c. part a estimate the total charge q on the cloud when the breakdown of the surrounding air is reached. express your answer numerically, to three significant figures, using ďµ0=8.85ă—10â’12c2/(nâ‹…m2) .

Because air contracts as it cools, the air pressure inside a freezer is typically lower than on the outside. why do ice cubes inside a freezer tend to shrink over time? a. the ice dissolves oxygen from the air, forming a denser crystalline matrix. b. the ice reacts chemically with carbon dioxide in the air, forming gaseous carbon compounds. c. the ice melts, and then the liquid freezes as ice crystals on the bottom of the freezer. d. the ice sublimes, and then the water vapor deposits as ice crystals on the sides of the freezer.

What is the speed of an object at a given moment?