Physics [2 Mark Question Answer]

The statement means that the effort required for the machine to overcome a load is less than the load.
(i) The crowbar,
(ii) The beam of the common balance.

The efficiency of a single movable pulley system is not 100% this is because
(i)The friction of the pulley bearing is not zero,
(ii)The weight of the pulley and string is not zero.

A pulley which has its axis of rotation fixed in position is called a fixed pulley.
A single fixed pulley is used in lifting a small load like a water bucket from the well.

Class II lever always has a mechanical advantage more than one.
Example: a nutcracker.
To increase its mechanical advantage we can increase the length of effort arm.

Levers of second order:
(i) Lock and key
(ii) Opener of soda water bottle
(iii) Closing a door

Levers of 1st order:
(i) Railway signal
(ii) Handle of water pump
(iii) Motor car foot brake
(iv) Nail cutter

The mechanical advantage of the second-order lever is always more than 1. This is because the effort arm is always longer than the load arm of these levers.

(i) Mechanical advantage = Velocity ratio.
(ii) Mechanical advantage is less than the velocity ratio as efficiency is less than one.

With the increase in the number of pulleys in the arrangement of block and tackle, the number of strands of string supporting the load increases and so its mechanical advantage increases.

A machine is a device by which we can overcome resistance by applying a comparatively small force at a convenient point and in the desired direction or obtain a gain in speed.

single movable pulley acts as a force multiplier.