A car engine is initially rotating at 250 rad/s. It is then turned off and takes 4.80 s to come to a complete stop. What is the angular acceleration of the engine

Question

asked Jan 4, 2021 145k views

1 Answer

IlyaSurmay · Answer 1 · 2021-01-08T11:45:17+0000

Answer:

$\alpha = 52.1$

Step-by-step explanation:

Given

$w_1 = 250\ rad/s$ --- initial angular velocity

t_2 = 4.8s -- Initial time

Because the engine completely stops, we have the following:

$w_2 = 0\ rad/s$ --- final angular velocity

t_1 = 0 --- final time

Required:

Determine the angular acceleration (
$\alpha$ )

The angular is calculated as thus:

$\alpha = (w_2 - w_1)/(t_2 - t_1)$

i.e. the ratio of change in angular velocity to change in time

Substitute in the required values, the expression becomes:

$\alpha = (250 - 0)/(4.8 - 0)$

$\alpha = (250)/(4.8)$

$\alpha = 52.08333$

$\alpha = 52.1$ -- approximated

Hence, the engine's angular acceleration is 52.1rad/s^2