To solve this problem it is necessary to apply the kinematic equations of Energy for which the rotation of a circular body is described as

Where,
m = Mass of the Vall
v = Velocity
I = Moment of inertia abouts its centre of mass
Angular speed
Basically the two sums of energies is the consideration of translational and rotational kinetic energy.
a. so that it was also rotating?
The ball is rotating means that it has some angular speed:


When there is a little angular energy (and not linear energy to travel faster), translational energy will be greater than the 1000J applied.

The ball will not go faster.
c. so that it wasn't rotating?
For the case where the angular velocity does not rotate it is zero therefore



All energy is transoformed into translational energy so it is possible to go faster. This option is CORRECT.
b. It makes no difference.
Although the order presented is different, I left this last option because as we can see with the previous two parts if there is an affectation regarding angular movement, therefore it is not correct.
Answer:
T = 686.7N
Explanation:
For this exercise we will use Newton's second law in this case there is no acceleration,
∑ F = ma
T -W = 0
The gymnast's weight is
W = mg
We clear and calculate the tension
T = mg
T = 70 9.81
T = 686.7N
This question deals with the law of conservation of momentum, which basically says that the total momentum in a system must stay the same, provided there are no outside forces. Since you were given the mass and velocity of the two objects you can find the momentum (p=mv) of each and then add them together to find the total momentum of the system before they collide. This total momentum must be the same after they collide. Since you have the mass and velocity of one of the objects after the collision you can find the its momentum after. Subtract this from the the system total and you will have the momentum of the other object after the collision. Now that you know the momentum of the other object you can find its velocity using p=mv and its mass from before.
Be careful with the velocities. They are vectors, so direction matters. Typically moving to the right is positive (+) and moving to the left is negative (-). It is not clear from your question which direction the objects are moving before and after the collision.
Option (a) is correct.
Change in volume during the band concert might have been caused by the constructive and destructive interference of sound waves.
Interference is the process of redistribution of energy when two or more waves superimpose on each other.When two sound waves which are in phase superimpose on each other, constructive interference takes place. During constructive interference , the amplitude of resulting waves increases.Thus the loudness of sound increases.
When two sound waves which are out of phase superimpose on each other, destructive interference takes place. During destructive interference , the amplitude of resulting waves decreases.Thus the loudness of sound decreases.
Answer:
Explanation:
Six waves passes by under 60second interval
Since it has 6 waves,
Then, it correspond to 3 wavelength
Then,
The period of each Each wavelength is 60 / 3
Then, period = 20seconds
From the relationship between frequency and period
f = 1 / T
f = 1 / 20
f = 0.05 Hz