Question

the wheel of a toy car rotates about a fixed axis. it slows down from 400rps to 200 rps in 2s. then, its angular retardation in rad/sec^2 is ...................

Answer 1

here ω initial = 400π/30 = 40π/ 3 rad.

ω final = 200π/30 = 20π/ 3 rad.

t= 2sec

ω final = ωinitial + αt

20π/3 - 40π/3 = α 2

α = - 10π/3 rad/sec^2

Answer 2

Given that,

Initial angular speed, $\omega_i=400\ rps=2513.27\ rad/s$

Final angular speed, $\omega_f=200\ rps=1256.64\ rad/s$

Time, t = 2 s

To find,

Angular retardation.

Solution,

Angular retardation is equal to the difference of final to the initial angular velocities of the wheel divided by time. It is given by :

$\alpha =\dfrac{\omega_f-\omega_i}{t}\\\\\alpha =\dfrac{1256.64-2513.27}{2}\\\\\alpha =-628.31\ rad/s^2$

So, the angular retardation of the wheel is $628.31\ rad/s^2$.

Learn more,

Angular acceleration

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