Answer:
225 rpm
Explanation:
The angular acceleration of the fan is given by:

where
is the final angular speed
is the initial angular speed
is the time interval
For the fan in this problem,

Substituting,

Now we can find the angular speed of the fan at the end of the 5th second, so after t = 5 s. It is given by:

where

Substituting,

Answer:
B) the change in momentum.
Explanation:
The impulse is defined as the product between the force applied on an object (F) and the duration of the collision (
):
(1)
We can rewrite the force by using Newton's second law, as the product between mass (m) and acceleration (a):

So, (1) becomes

Now we can also rewrite the acceleration as ratio between the change in velocity and change in time:
. If we substitute into the previous equation, we find

And the quantity
is equivalent to the change in momentum,
.
Answer:
Final velocity, V = 11.5m/s
Explanation:
Given the following data;
Initial velocity, U = 2.5m/s
Acceleration, a = 1.5m/s²
Time, t = 6secs
To find the final velocity, we would use the first equation of motion
V = U + at
Substituting into the equation, we have
V = 2.5 + 1.5*6
V = 2.5 + 9
Final velocity, V = 11.5m/s
First convert the speed of sound from meters/second to miles/second:

Then the time it takes for the sound to travel 20 miles is
