Mechanical advantage of a machine is defined as :

1. Load x Effort
2. $\dfrac{\text {Load}}{\text {Effort}}$
3. Load + Effort
4. $\dfrac{\text {Effort}}{\text {Load}}$

The mechanical advantage of a lever is equal to :

1. $\dfrac{\text {Load Arm}}{\text {Effort Arm}}\\[0.5 em]$
2. $\dfrac{\text {Effort Arm}}{\text {Load Arm}}$
3. Load Arm + Effort Arm
4. Load Arm - Effort Arm

A pulley is used because it :

1. has the mechanical advantage greater than one
2. has 100% efficiency
3. helps to apply the force in a convenient direction
4. requires more effort to raise a less load.

Wheel is used with axle because :

1. sliding friction is less than the rolling friction
2. rolling friction is less than the sliding friction
3. they work as the inclined plane
4. they help us to change the direction of force.