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Which of the following statements is true about the efficiency of a machine?

The efficiency of a machine is always less than 100% due to energy losses like friction.

A machine can only be efficient if there is no friction.

Efficiency is the ratio of input energy to output energy.

Efficiency is always greater than 100%.

What is a machine?

A device that changes the direction of the applied force.

A device that does not require force to work.

A device that helps in doing work by transmitting or transforming energy.

A device that reduces the amount of force required to do work.

In which of the following applications is a pulley used in a building site?

To lift heavy building blocks horizontally.

To lift cement bags.

To measure the force applied to a load.

To reduce friction.

Which of the following is an example of a third-class lever?

Wheelbarrow.

Scissors.

Fishing rod.

Crowbar.

What is the Mechanical Advantage (MA) of a machine?

The ratio of the output force to the input force.

The ratio of the input force to the output force.

The ratio of the velocity output to the velocity input.

The ratio of the distance moved by the load to the distance moved by the effort.