Question

Find the reading of spring balance as shown in figure. Assume that mass $M$ is in equilibrium and all surfaces are smooth.

• A. 8 N
• B. 9 N
• C. 12 N
• D. Zero

Answer 1

The correct option is C 12 N


$N=\text{mg cos}{37}^{\circ }$
$N=2.5\times 10\times \frac{4}{5}$
$\text{N = 20 N}$
Reading of spring balance (R),
$R=\text{N cos}{53}^{\circ }$
$R=20\times \frac{3}{5}$
$\text{R = 12 N}$