Question

A heavy block kept on a frictionless surface and being pulled by two ropes of equal mass $m$ as shown in the figure. At $t=0$, the force on the left rope is withdraw but the force on the right end continues to act, Let $F_1$ and $F_2$ be the magnitudes of the force by the right rope and the left rope on the block respectively.

• A. $F_1=F_2=F$ for $t<0$
• B. $F_1=F_2=F+mg$ for $t<0$
• C. $F_1=F_1{F}_2=F$ for $t>0$
• D. $F_1<F_1{F}_2=F$ for $t>0$

Answer 1

The correct option is A $F_1=F_2=F$ for $t<0$

At $t=o$, the force on the left rope is withdraw but the force on the right end continue to act .

Let $F_1$ and $F_2$ be the magnitude of the force by the right rope and the left rope on the block.

In this case, $F_1$ =$F_2$ =$F$ for $t<0$ because there is a static friction produced at $t<0$ which produce equal and opposite force on the block.