Question

Section 14.3 Mechanical Advantage
and Efficiency
(pages 421–426)
This section describes mechanical advantage and efficiency and how to calculate these
values. It also discusses ways to maximize mechanical advantage and efficiency.
Reading Strategy (page 421)
Building Vocabulary As you read the section, write a definition in the table
for each vocabulary term in your own words. For more information on this
Reading Strategy, see the Reading and Study Skills in the Skills and
Reference Handbook at the end of your textbook.
Mechanical Advantage
Vocabulary Definition
Mechanical The number of times a machine increases force
advantage
Mechanical Advantage (pages 421–423)
1. The number of times that a machine increases an input force is the
of the machine.
2. Circle the letter of the correct answer. For a given input force, what
affects the output force that a nutcracker can exert on a nut?
a. the location of the hand holding the nutcracker
b. the angle of the legs of the nutcracker
c. the position of the nut
3. Mechanical advantage describes the relationship between input force
and force.
4. Is the following sentence true or false? A loading ramp with a rough
surface has a greater mechanical advantage than one with a smooth
surface.
Physical Science Reading and Study Workbook Level B ■ Chapter 14 165
© by Savvas Learning Company LLC. publishing

Answer 1

Mechanical Advantage answers:

1. The number of times that a machine increases an input force is the mechanical advantage of the machine.

2. c. the position of the nut
- For a nutcracker (a lever), the output force depends on the distances from the fulcrum to the input and to the nut; moving the nut changes the output force for the same input.

3. Mechanical advantage describes the relationship between input force and output force.

4. False.
- A rough surface increases friction, which raises the required input force and thus reduces the actual mechanical advantage (the ideal MA set by ramp geometry is unchanged).