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)

answer: 802.3 kilo joules of energy represents 191.75 kilo calorie of energy.

explanation:

energy released during combustion of one mole methane = 802.3 kilo joules

if 1 kilo joule = 0.239006   kilo calorie

then ,802.3 kilo joule will be = 802.30.239006 kilo calorie

802.3 kilo joule = 191.75 kilo calorie

hence, the energy in kilo calorie is 191.75 kilo calorie.

the answer is neither ball has a charge.

because if they were both positively charged, they will repel each other.

if they were positively and negatively charged, they will seek.