Question
A rod PQ of length l is moving with ends remaining in contact with frictionless wall and floor. If at the instant, shown the velocity of end Q is 2 m/s towards negative direction of x. The speed of end P will be
Solution
B.
From the diagram in question
x = l cosθ
y = l sinθ
∴ = -l sinθ .....
vy = = l cosθ
∴ .....
vy = - vx cot θ
Since vx = -2 m/s
vy = -2 cot 60o ....( Given:- θ = 60o )
=
vy = ms-1
The negative sign indicates the motion towards negative direction of Y.