How many movable pulleys are there in a system of  $3$ pulleys? What is the mechanical advantage and velocity ratio of this system? If efficiency of system is $100\%$, what effort is needed to lift a load of $350 \mathrm{kgf}$ attached to it?

The figure given alongside shows a block and tackle system of $4$ pulleys. Draw a string around the pulleys. Show also the position and the direction of the effort to be applied on this string. What is the mechanical advantage and velocity ratio of this system?

Give examples where a gear system is used to obtain gain in torque.

Give examples where a gear system is used to obtain gain in speed.