Answer:
The sum of PE and KE remains constant
Explanation:
Sound waves are changes in pressure generated by vibrating molecules. The physical characteristics of sound waves influence the three psychological features of sound: loudness, pitch, and timbre. Loudness depends on the amplitude,or height, of sound waves. The greater the amplitude, the louder the sound perceived.
Answer:
<u>Searching in google I found the total mass and the radius of the ball (m = 1.5 kg and r = 10 cm) which are needed to solve the problem!</u>
The ball rotates 6.78 revolutions.
Explanation:
<u>Searching in google I found the total mass and the radius of the ball (m = 1.5 kg and r = 10 cm) which are needed to solve the problem!</u>
At the bottom the ball has the following angular speed:

Now, we need to find the distance traveled by the ball (L) by using θ=28° and h(height) = 2 m:
To find the revolutions we need the time, which can be found using the following equation:
(1)
So first, we need to find the acceleration:
(2)
By entering equation (2) into (1) we have:

Since it starts from rest (v₀ = 0):

Finally, we can find the revolutions:

Therefore, the ball rotates 6.78 revolutions.
I hope it helps you!
Explanation:
It is given that, the position of a particle as as function of time t is given by :

Let v is the velocity of the particle. Velocity of an object is given by :

![v=\dfrac{d[(8t+9)i+(2t^2-8)j+6tk]}{dt}](https://tex.z-dn.net/?f=v%3D%5Cdfrac%7Bd%5B%288t%2B9%29i%2B%282t%5E2-8%29j%2B6tk%5D%7D%7Bdt%7D)

So, the above equation is the velocity vector.
Let a is the acceleration of the particle. Acceleration of an object is given by :

![a=\dfrac{d[8i+4tj+6k]}{dt}](https://tex.z-dn.net/?f=a%3D%5Cdfrac%7Bd%5B8i%2B4tj%2B6k%5D%7D%7Bdt%7D)

At t = 0, 

Hence, this is the required solution.