Question

58. Two blocks A and B are connected through a string
as shown in figure. If velocity of block A is 5 m/s at
given instant, then velocity of block B (in m/s) at the
same instant is given by (Given theta 1= 60°,
theta 2 = 37°)
​

Answer 1

Given:

Two blocks A and B are connected through a string as shown in figure. Velocity of block A is 5 m/s at given instant.

To find:

Velocity of block B.

Calculation:

In this type of questions , it is best to apply the rule of constraint as both the blocks are are connected by a single string.

Due to constraint in movement , the velocity component of both the blocks along the the string will be equal.

Let Velocity of block B be u ; so velocity component along the string will be $u\cos(\theta1)$.

Similarly , velocity component of the block A along the string will be $5\cos(\theta2)$.

These velocity components should be equal:

$\therefore \: u \cos( \theta1) = 5 \cos( \theta2)$

$= > \: u= \dfrac{5 \cos( \theta2) }{ \cos( \theta1) }$

$= > \: u= \dfrac{5 \cos({37}^{\circ}) }{ \cos({60}^{\circ}) }$

$= > \: u= \dfrac{5\times\frac{4}{5}}{\frac{1}{2}}$

$=> \: u = 10 m/s$

So, Velocity of block B is 10 m/s.

Answer 2

Answer:

the correct answer is 8 Hope me