Friction is the force you get when you (for example) Rub something with another, it's a force that may generate heat and even some resistance. Another example is rubbing your hands together, they get hot, therefore friction is working, without friction you wouldn't be able to stop moving.
Answer:
Juan and Kuri complete one revolution in the same time, but Juan travels a shorter distance and has a lower speed.
Explanation:
Since Juan is closer to the center and Kuri is away from the center so we can say that Juan will move smaller distance in one complete revolution
As we know that the distance moved in one revolution is given as

also the time period of revolution for both will remain same as they move with the time period of carousel
Now we can say that the speed is given as

so Juan will have less tangential speed. so correct answer will be
Juan and Kuri complete one revolution in the same time, but Juan travels a shorter distance and has a lower speed.
1. C. Gravitational attraction exists between the two objects.
Explanation:
Gravitational attraction is always exerted between two objects which have mass, and its magnitude is given by:

where G is the gravitational constant, m1 and m2 the masses of the two objects, and r the separation between them. Since the two objects have for sure non-zero masses m1 and m2, even if they are 20 miles apart, the value of the gravitational attraction F is non-zero, so the correct answer is C.
2. D. Two atoms come together to form a molecule.
Explanation:
this outcome is actually caused by the electrostatic forces between the two atoms, not by gravitational force. In fact, gravitational force becomes relevant only when the masses of the two objects involved are large enough: this is the case for planets, stars, galaxies, and objects in the universe. However, two atoms have very small masses, so the gravitational force between them is really negligible. On this smaller scales, the electrostatic force is much stronger than the gravitational force, so the electrostatic force is the real responsible for the formation of bonds between atoms.
Answer:
"h" signifies Planck's constant
Explanation:
In the equation energy E = h X v
The "h" there signifies Planck's constant
Planck's constant is a value, that shows the rate at which the energy of a photon increases/decreases, as the frequency of its electromagnetic wave changes.
It was named after Max Planck who discovered this unique relationship between the energy of a light wave and its frequency.
Planck's constant, "h" is usually expressed in Joules second
Planck's constant = 
when it reaches the maximum height, all the energy has now been converted into potential energy.when a ball is thrown straight upto into the air,all its initial kinetic energy converted into gravitational potential energy when it reaches its maximum height