Answer:

Explanation:
The angular acceleration is:


And the angular deceleration is:


The total number of revolutions is:



<u>Answer:</u>
The acceleration of the car is 
<u>Explanation:</u>
In the question it is given that car initially heads north with a velocity
. It then accelerates for
and in the end its velocity is
.
initial velocity 
time 
final velocity 
The equation of acceleration is


The value of acceleration is positive, here since the car is speeding up. If it was slowing down the value of acceleration would be negative.
2.4 secs I think
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Explanation:
We have,
Mass of an automobile is 1150 kg
The automobile traveling at 86 km/h and then it comes to stop.
86 km/h = 23.88 m/s
It is required to find work done by the automobile.
Concept used : Work energy theorem
Th change in kinetic energy of an object is equal to the work done by it. The work done is then given by :

Here, v = 0

or

Therefore, the work done by the automobile is
.