Mechanical Advantage

Definitions / 定义

100

What is work in science? / 科学中什么是功？
A) Force applied over a distance
B) Effort without movement
C) Any physical activity
D) Only lifting objects

A) Force applied over a distance

200

What is a machine? / 机器是什么？
A) Any electronic device
B) A tool that helps make work easier
C) A heavy object
D) A type of energy

B) A tool that helps make work easier

300

What is input force? / 输入力是什么？
A) Force applied by the machine
B) The force applied by the user
C) Output divided by work
D) Any moving force

B) The force applied by the user

400

What is output force? / 输出力是什么？
A) Force applied to the object
B) Force you put in
C) Work done by friction
D) Force in newtons squared

A) Force applied to the object

500

What is mechanical advantage? / 机械优势是什么？
A) Speed of a machine
B) How much a machine helps you
C) Energy wasted
D) Input × Output

B) How much a machine helps you

Simple Machines / 简单机器

100

Which is a flat surface used to raise objects? / 哪种是用来抬起物体的平面？
A) Lever
B) Inclined plane
C) Pulley
D) Wheel and axle

B) Inclined plane

200

Which rotates around a central axis? / 哪种围绕中心轴旋转？
A) Pulley
B) Wedge
C) Wheel and axle
D) Screw

C) Wheel and axle

300

Which can split objects or hold them? / 哪种可以分开或固定物体？
A) Wedge
B) Pulley
C) Lever
D) Inclined plane

A) Wedge

400

Which changes the direction of force? / 哪种改变力的方向？
A) Lever
B) Pulley
C) Screw
D) Wedge

B) Pulley

500

Which uses a bar and a fulcrum? / 哪种使用杠杆和支点？
A) Lever
B) Pulley
C) Inclined plane
D) Wedge

A) Lever

Mechanical Advantage / 机械优势

100

MA formula? / MA公式？
A) MA = Input ÷ Output
B) MA = Output ÷ Input
C) MA = Force × Distance
D) MA = Work ÷ Time

B) MA = Output ÷ Input

200

Output = 100 N, Input = 50 N. MA = ? / 输出力=100 N，输入力=50 N，MA=?
A) 0.5
B) 1
C) 2
D) 3

C) 2

300

True or False: MA < 1 is useless. / 正确或错误：MA<1无用
A) True
B) False

B) False

400

A pulley lifts 200 N with 50 N effort. MA = ? / 滑轮用50 N力举起200 N，MA=?
A) 2
B) 3
C) 4
D) 5

C) 4

500

Ramp 6 m long, 2 m high. Ideal MA = ? / 坡道长6米，高2米，理想MA=?
A) 2
B) 3
C) 4
D) 5

B) 3

Efficiency / 效率

100

Efficiency formula? / 效率公式？
A) Input ÷ Output × 100
B) Output ÷ Input × 100
C) Output × Force ÷ Input
D) Input × Distance ÷ Output

B) Output ÷ Input × 100

200

Input Work = 300 J, Output Work = 240 J. Efficiency = ? / 输入功=300焦耳，输出功=240焦耳，效率=?
A) 70%
B) 75%
C) 80%
D) 85%

C) 80%

300

True or False: Efficiency >100% is possible. / 正确或错误：效率>100%可能
A) True
B) False

B) False

400

Friction increases, efficiency will: / 摩擦增加，效率会：
A) Increase
B) Decrease
C) Stay the same
D) Double

B) Decrease

500

Output Work = 500 J, Efficiency = 50%, Input Work = ? / 输出功=500焦耳，效率=50%，输入功=?
A) 250 J
B) 500 J
C) 750 J
D) 1000 J

D) 1000 J

Real-Life Examples / 生活中的例子

100

Helps move heavy objects up a slope? / 帮助把重物搬上坡的机器？
A) Pulley
B) Lever
C) Ramp
D) Screw

C) Ramp

200

A seesaw is an example of which simple machine? / 跷跷板是哪个简单机器的例子？
A) Pulley
B) Lever
C) Inclined plane
D) Wheel and axle

B) Lever

300

A flagpole pulley changes the ______ of force. / 升旗滑轮改变力的______。
A) Magnitude
B) Direction
C) Distance
D) Speed

B) Direction

400

Using a crowbar increases ______ force. / 使用撬棍会增加______力。
A) Input
B) Output
C) Friction
D) Work

B) Output

500

Sliding a box up a ramp reduces . / 用坡道推箱子会减少。
A) Distance
B) Input force
C) Output force
D) Work

B) Input force