Question

Hlo guys.....
A wheel is initially at rest now it is rotated with angular acceleration .It rotates through angle "theta 1" in first one second and through additional angle "theta2" in next one second .Find theta2/theta1​

Answer 1

Answer:

First of all, you need to remember the relationship between angular displacement (theta) , angular acceleration and time.

Let angular acceleration be "a",

time taken be "t" , angular displacement be "theta" and angular velocity be "w"

so the relationship is

[Theta = w*t + 1/2 * a* t^2]

Theta1 is the angular displacement in the 1st second.

So,

Theta1 = w*1 + 1/2* a* 1^2

=> Theta1 = 0 + a/2

[ initial angular velocity (i.e "w") is zero as the body starts from rest]

Theta2 is the angular displacement in the 2nd second.

Let Theta3 be angular displacement in 2 seconds.

Theta3 = w*2 + 1/2 *a* 2^2

=>Theta3 = 0 + 2a

Theta2 is obtained by :

subtracting theta1 from theta3

So theta2 = 2a - a/2 = 3a/2.

The required ratio :

theta2/ theta1= (3a/2)/(a/2) = 3:1

THE ANSWER IS :

RATIO = 3:1