Answer:
Kinetic energy is energy possessed by a body by virtue of its movement. Potential energy is the energy possessed by a body by virtue of its position or state. While kinetic energy of an object is relative to the state of other objects in its environment, potential energy is completely independent of its environment.
Explanation:
working...
Sound wave needs medium to travel
as energy which travels in this wave is because of transfer from one particle to another particle
If there is no medium then energy can not be transferred and sound wave will not travel
so in vacuum we can not listen sound
similarly here air is removed it means there is no medium inside the jar to travel the sound and hence we can not hear it
Option B is correct
Without air, the sound waves cannot travel to the ear.
Answer:
The force applied on one wheel during braking = 6.8 lb
Explanation:
Area of the piston (A) = 0.4 
Force applied on the piston(F) = 6.4 lb
Pressure on the piston (P) = 
⇒ P = 
⇒ P = 16 
This is the pressure inside the cylinder.
Let force applied on the brake pad = 
Area of the brake pad (
)= 1.7 
Thus the pressure on the brake pad (
) = 
When brake is applied on the vehicle the pressure on the piston is equal to pressure on the brake pad.
⇒ P = 
⇒ 16 = 
⇒
= 16 × 
Put the value of
we get
⇒
= 16 × 1.7
⇒
= 27.2 lb
This the total force applied during braking.
The force applied on one wheel =
=
= 6.8 lb
⇒ The force applied on one wheel during braking.
Answer:
82780.42123 m/s
14.45 days
Explanation:
m = Mass of the planet
M = Mass of the star = 
r = Radius of orbit of planet = 
v = Orbital speed
The kinetic and potential energy balance is given by

The orbital speed of the star is 82780.42123 m/s
The orbital period is given by
The orbital period is 14.45 days