Question

An object of mass $5kg$is attached to the hook of a spring balance and the balance is suspended vertically from the roof of a lift. The reading on the spring balance when the lift is going up with an acceleration of $0.25m{s}^{-2}$ is taken, (take,$g=10m{s}^{-2}$)

• A. $51.25N$
• B. $48.75N$
• C. $52.75N$
• D. $47.25N$
• E. $55N$

Answer 1

The correct option is A

$51.25N$

Step 1. Given data:

Gravity,$g=10m{s}^{-2}$

Mass,$m=5kg$

Acceleration,$a=0.25m{s}^{-2}$

Step 2. Find weight :

When the lift is going upwards

$F=mg+ma$

Force will be equal to the weight

$W=mg+ma$

$=m(g+a)$

$=5(10+0.25)$

$=51.25N$

Hence, (A) is the correct option.