Answer:
Angular acceleration, is 
Explanation:
Given that,
Initial speed of the drill, 
After 4.28 s of constant angular acceleration it turns at a rate of 28940 rev/min, final angular speed, 
We need to find the drill’s angular acceleration. It is given by the rate of change of angular velocity.

So, the drill's angular acceleration is
.
Answer:d
Explanation:
Given systems are state of matter and do not contain any heat instead Heat is required to change Phase or raise the temperature of the particular system.
For example 600 kg of ice at 
Heat Required to convert it to water at
is

Where L=latent heat of Fusion 


Well simple the warm water then replaces the cold current that sinks to the ocean floor.
Answer:
a.Beth
b.2232 s
Explanation:
We are given that
Distance,d=400 mi
Speed of Alan,v=45 mph
Speed of Beth,v'=55 mph
a.Time =
Using the formula
Time taken by Alan=
Time taken by Beth=
Alan will reach San Francisco at 4:53 PM
Beth will reach San Francisco at 4:16 PM
Beth will reach before Alan.
b.Difference between time=8.89-7.27=1.62 hr
t=1.62 hr
1.62-1=0.62 hr
0.62 hr=
Hence, Beth has to wait 2232 s for Alan to arrive .