A car comes to a stop in 3 s from the moment the driver applies the brakes. If the initial angular velocity of the tires was 57 rad/s, what is their angular acceleration (assumed constant) over this time interval

-19rad/s

Explanation:

Given

Initial angular velocity w0 = 57rad/s

Time = 3s

Final angular velocity wf = 0rad/s (car comes to stop)

Required

angular acceleration (α)

Using the equation of motion

wf = w0 + αt

Substitute the given value and get α;

0 = 57 + 3α

-57 = 3α

α = -57/3

α = -19rad/s (the negative sign shows that the car decelerated over time)

electrical power

momentum of soft ball three times less than baskey ball