Answer:
m=ρV
V=4/3 * pi * r3
V=1.3 * 3.14 * 3.9^3
V=242.14 cm^3
m=7.58 * 242.14
m=1.8 kG
Explanation:
1. We calculate volume for sphere.
2. Then we calculate mass of sphere.
The work done by the normal force n when the box slides down a frictionless incline and gaining speed is zero.
<h3>What is normal force?</h3>
The force of contact is called the normal force. When the two surfaces are in contact with each other, then the normal force acts.
This force is applied by the solid bodies on each other in order to prevent the passing through each other.
A box slides down a frictionless incline, gaining speed. For this box, the value of work done by normal force has to be found out. Let's analyze the given condition.
- The body is gaining the speed, which means there is a change in kinetic energy.
- The change in kinetic energy is equal to the work done.
- The friction force is the product of coefficient of the friction and normal force.
- The friction force for the given case is zero. Thus, the normal force must be equal to the zero.
Thus, the work done by the normal force n when the box slides down a frictionless incline and gaining speed is zero.
Learn more about the normal force here;
brainly.com/question/10941832
It's weird but technically correct to say that a radio wave can be considered a low-frequency light wave. Radio and light are both electromagnetic waves. The only difference is that radio waves have much much much longer wavelengths, and much much much lower frequencies, than light waves have. But they're both the same physical phenomenon.
However, a radio wave CAN'T also be considered to be a sound wave. These two things are as different as two waves can be.
-- Radio is an electromagnetic wave. Sound is a mechanical wave.
-- Radio waves travel more than 800 thousand times faster than sound waves do.
-- Radio waves are transverse waves. Sound waves are longitudinal waves.
-- Radio waves can travel through empty space. Sound waves need material stuff to travel through.
-- Radio waves can be detected by radio, TV, and microwave receivers. Sound waves can't.
-- Sound waves can be detected by our ears. Radio waves can't.
-- Sound waves can be generated by talking, or by hitting a frying pan with a spoon. Radio waves can't.
-- Radio waves can be generated by an alternating current flowing through an isolated wire. Sound waves can't.
Answer:
I think it's 0 N 3rd choice
