Question

A box of mass $70kg$ is being lifted by a helicopter with the help of a rope, which can bear a maximum tension of $100kg$ wt. The maximum acceleration with which helicopter should rise so that the rope does not break will be (Given $g=9.8m/s^2$)

• A. $3m/s^2$
• B. $4.2m/s^2$
• C. $5.4m/s^2$
• D. $6.1m/s^2$

Answer 1

The correct option is B $4.2m/s^2$

Let $a$ be the maximum acceleration of the helicopter and $T$ be the tension in the rope
$T-mg=maT=m(g+a)100\times 9.8=70(9.8+a)a=\frac{30\times 9.8}{70}=4.2m/s^2$