Question

An old wheat-grinding wheel in a museum actually works. The sign on the wall says that the wheel has a rotational acceleration of 180 rad/s 2 as its spinning rotational speed increases from zero to 1700 rpm. How long does it take the wheel to attain this rotational speed?

Answer 1

It will take 0.989 second to attain this speed

Explanation:

In this question, we want to calculate the time it will take for the wheel of the machine to attain the given rotational speed

We proceed as follows;

From the question, we can identify the following parameters

Rotational acceleration of the wheel is, α = 180 rad/s^2

Initial spinning rotational speed of the wheel is, ω= 0 rpm

1 rpm = (1/60) revolution per second = 2π * (1/60) rad/s

Thus,

initial rotational speed ωi = 0 rad/s

Final spinning rotational speed ωf of the wheel is, = 1700 rpm =178.02 rad/s

Now, from the equations of motion (for rotational motions),

ωf = ωi + αt

where t is the time taken by the wheel to attain its final rotational speed.

178.02= 0 + 180 * t

t = 178.02/180

t = 0.989 second