The frequency of the wave is 4 Hz
Answer:
When thermal energy is added to a substance, its temperature increases, which can change its state from solid to liquid (melting), liquid to gas (vaporization), or solid to gas (sublimation). ... When the pressure exerted on a substance increases, it can cause the substance to condense.
Explanation:
Hope it will help use
My inference is that the water molecules are moving up and down. I don't know for sure but i'm usually correct.
Answer:
The force exerted by the floor is 80 N.
Explanation:
Given that,
Mass of ball = 0.5 kg
Velocity= 4 m/s
Time t = 0.05 s
When the ball rebounds then the kinetic energy is

Where, m = mass of ball
v = velocity of ball
Put the value into the formula


The average force exerted by the floor on the ball = change in kinetic energy over collision time


Hence, The force exerted by the floor is 80 N.
Answer: 
Explanation:
We are told both planets describe a circular orbit around the star S. So, let's approach this problem begining with the angular velocity
of the planet P1 with a period
:
(1)
Where:
is the velocity of planet P1
is the radius of the orbit of planet P1
Finding
:
(2)
(3)
(4)
On the other hand, we know the gravitational force
between the star S with mass
and the planet P1 with mass
is:
(5)
Where
is the Gravitational Constant and its value is 
In addition, the centripetal force
exerted on the planet is:
(6)
Assuming this system is in equilibrium:
(7)
Substituting (5) and (6) in (7):
(8)
Finding
:
(9)
(10)
Finally:
(11) This is the mass of the star S