A medium is a substance or material that carries the wave. Sounds waves need a medium in order to travel through a wave to help it travel as it cannot travel through a vacuum. Mechanical waves need a medium to transport energy.
Answer:
The magnitude of the force exerted on the ball by the racquet is 94.73 N.
Explanation:
The force exerted on the ball is the following:

Where:
m: is the mass of the ball = 59 g
a: is the acceleration
The acceleration of the ball can be found with the following kinematic equation:

Where:
d: is the distance = 0.36 m
: is the final speed = 34 m/s
: is the initial speed = 0 (it start from rest)
Hence, the acceleration is:

Finally, the force is:
Therefore, the magnitude of the force exerted on the ball by the racquet is 94.73 N.
I hope it helps you!
Answer:
Option B) The fuel for nuclear fusion comes from sea water
Explanation:
Nuclear fusion can not be carried out by using any type of water as water is composed of stable water molecules (
which is quite difficult to be decayed by any simple method.
Moreover, fusion reactions demands the combination of nuclei of lighter elements for which it makes use of the heavy isotopes of Hydrogen that are Deuterium and Tritium as fuel to carry out the nuclear fusion.
Explaination :
Momentum = mass x speed
p = (30 kg) (3 m/s)
p = 90 kg m/s