MA/VR/efficiency

A simple lever is a rigid bar which pivots at a point called the

• fulcrum
• center of rotation
• hinge
• anchor

The input force on a lever is called the

• resistance force

• effort force

• load force
• fulcrum force

The output force on a lever is called the

(a)  

Mechanical advantage is

• a measure of the speed amplification achieved by using a tool, mechanical device, or machine system
• a measure of the energy consumption achieved by using a tool, mechanical device, or machine system
• a measure of the force reduction achieved by using a tool, mechanical device, or machine system
• a measure of the force amplification achieved by using a tool, mechanical device, or machine system

Using a lever, the person can raise a load of 2400 N using an effort of 350 N. Calculate the mechanical advantage.

• 7.2
• 8.3
• 6.9

• 5.5

You have a simple inclined plane with a length of 6 meters and a height of 2 meters. A 100 kg object is placed on this inclined plane. Calculate the velocity ratio when this object is allowed to slide down the inclined plane under the influence of gravity.

• 6
• 4
• 2
• 3

Roger invented a machine that would do his work for him. His machine used 5.6 N and produced 11 N.  What is the mechanical advantage of this machine?

• 1.96

• 3.14

• 0.50

• 2.50

A mechanism has a mechanical advantage of 4 and a velocity ratio of 5. Calculate the efficiency of the mechanism.

• 1.25

• 0.80

• 0.20

• 0.24

A mechanism has the load arm move 1.2 m when the effort arm moves 2 m. Calculate the velocity ratio.

• 0.60

• 2.4

• 1.67

• 0.24

A machine has an efficiency of 80%. If the velocity ratio of the machine is 3.95, calculate the mechanical advantage.

• 3.16
• 5.25
• 4.94

• 2.50