Given:
initial angular speed, 
= 21.5 rad/s
final angular speed, 
= 28.0 rad/s
time, t = 3.50 s
Solution:
Angular acceleration can be defined as the time rate of change of angular velocity and is given by:
Now, putting the given values in the above formula:
Therefore, angular acceleration is:
I think they decrease echo and reduce noise, they do this by either absorbing vibrations or by scattering the sound so that echoes arrive at different times rather than reverberating as a standing wave. An echo is a reflection of a sound that arrives at the listener with a delay after the direct sound. The delay is usually proportional to the distance of the reflecting surface from the source and the listener.
The scientists describe them as D. Elliptical
Answer:
50 N/m
Explanation:
Elastic energy = kinetic energy
EE = KE
½ kx² = ½ mv²
½ k (4 m)² = ½ (8.0 kg) (10.0 m/s)²
k = 50 N/m
Answer:
Explanation:
We must use conservation of linear momentum before and after the collision, 
Before the collision we have:
where these are the masses are initial velocities of both players.
After the collision we have:
since they clong together, acting as one body.
This means we have:
Or:
Which for our values is:
