11 Y
What I Have Learned
Fill in the blanks with the correct word to complete each sentence.
Choose your answer inside the box and write it on your answer sheet.
more
sun
distance
gravitational force
less
moon
weightlessness
weightiness
mass
1. The greater the object's mass, the
gravity it exerts.
2. The greater the
or the shorter the
the stronger the
gravity is.
3. All objects are attracted toward the center of the earth due to
4. The
pulls the water from the oceans to make the tides.
5. The astronauts appear to float in space because of
inside the
spaceship.
​

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) .

What is the coefficient of kinetic friction μk between the block and the tabletop?

Select all the correct answers. which changes will increase the rate of reaction during combustion? decreasing the area of contact between the reactants adding more oxygen to the reaction removing heat from the reaction changing the reactants from solid form to powdered form lowering the exposure of the reactants to air