Question

When a person throws a meter stick it is found that the centre of the stick is moving with a speed of $10m/s$ vertically upwards & left end of stick with a speed of $20m/s$ vertically upwards. Then the angular speed of the stick is:

• A. $20rad/\sec$
• B. $10rad/\sec$
• C. $30rad/\sec$
• D. None of the above

Answer 1

The correct option is A $20rad/\sec$

Given: when a person throws a meter stick it is found that the centre of the stick is moving with a speed of 10 m/s vertically upwards & left end of stick with a speed of 20 m/s vertically upwards.

To find the angular speed of the stick

Solution:

Let $r$ be the distance between the end point and center of the stick

Here

$r=\frac{l}{2}=\frac{1}{2}m$

As per the given criteria,

speed of center of the stick, $v=10m/s$

and speed of left end of the stick, $V_P=20m/s$

And

$V_P=v+r\omega ⟹20=10+\frac{1}{2}\omega ⟹\omega =20rad/s$

is the angular speed of the stick