Question

A student is weighing an object using a spring balance, which shows a reading of $5Kg$. If the boy loses grip and the spring balance along with the object falls under gravity, then the weight as measured by the spring balance and mass of the object are respectively :

$(g=10m/s^2)$

• A. $0N,0kg$
• B. $50N,5kg$
• C. $0N,2.5kg$
• D. $0N,5kg$

Answer 1

The correct option is D $0N,5kg$

Mass of the object $m=5kg$

When the spring balance is fixed :

Weight measured $W=mg=5\times 10=50N$

Downward acceleration of the spring balance $a=g=10m/s^2$

Weight measured by spring balance $W^{\prime }=mg-ma$

$\therefore$ $W^{\prime }=50-5\times 10=0N$

Since, mass of the object does not change. So mass of the object even when the spring balance falls under gravity is $5kg$.