Question

A ball of mass $1kg$ is at rest in position P by means of two light stings OP and RP. The string RP is now cut and the ball swings to position Q. Find the tensions in the strings in positions OP (when RP was not cut ) and OQ (when RP was cut). (Take g= $10m/s^2$).

Answer 1

In the first case, ball is in equilibrium (permanent rest). Therefore, net force on the ball in any direction should be zero.
$\therefore \left(\Sigma \overrightarrow{F}\right)$ in vertical direction $=0$
or $T_1\cos \theta =mg$
or $T_1=\frac{mg}{\cos \theta }$
Substituting $m_1=1kg,g=10m/s^2$
and $\theta ={45}^{\circ }$
we get, $T_1=10\sqrt{2}N$