Simple Machines (简单机械)
What type of simple machine is an axe?
问题: 斧头是哪种简单机械
A wedge. (楔子)
What is work measured in?
🔹 问题: 功是用什么单位测量的？
Joules (焦耳).
What is a mechanical system?
🔹 问题: 什么是机械系统？
A system that changes force and motion. (一个改变力和运动的系统).
What is the force of gravity on a 5 kg object if Earth's gravity is 9.8 N/kg?
问题: 如果地球的重力为 9.8 N/kg，质量为 5kg 的物体受到的重力是多少？
49 N (9.8 × 5).
What simple machine is used in a ski lift?
问题: 滑雪缆车使用了哪种简单机械？
Pulley (滑轮).
Q: What is an example of a pulley?
问题: 滑轮的一个例子是什么？
A flagpole or an elevator. (旗杆或电梯)
What kind of force is used when kicking a soccer ball?
🔹 问题: 踢足球时使用了哪种力？
Contact force (接触力).
What are the three elements of a mechanical system?
🔹 问题: 机械系统的三个组成部分是什么？
Input, process, output. (输入，过程，输出).
What is the equation for work?
问题: 功的计算公式是什么？
Work = Force × Distance (W = Fd). | 功 = 力 × 距离 (W = Fd)。
What force helps slow down a snowboarder?
问题: 什么力可以减慢单板滑雪运动员的速度？
Friction (摩擦力).
Q: What simple machine is used in a screwdriver?
🔹 问题: 螺丝刀使用了哪种简单机械？
A screw. (螺丝)
What happens when force is applied but no motion occurs?
🔹 问题: 当施加了力但没有运动时会发生什么？
No work is done. (没有做功)
Give an example of a mechanical system.
🔹 问题: 说出一个机械系统的例子。
A car engine. (汽车引擎).
How much work is done when pushing a 100N object 3m?
问题: 用 100N 的力推动物体 3 米，做了多少功？
300 Joules (100 × 3).
What simple machines help move luggage?
问题: 哪些简单机械可以帮助搬运行李？
Wheel and axle, lever. (轮轴，杠杆).
Q: Name two simple machines in a bicycle.
🔹 问题: 自行车中有哪些两种简单机械？
Wheel and axle, and lever. (轮轴和杠杆)
: What is the equation for work?
🔹 问题: 功的计算公式是什么？
Work = Force × Distance
(功 = 力 × 距离).
What simple machines are used in an airport conveyor belt?
问题: 机场传送带使用了哪些简单机械？
Wheel and axle, pulley. (轮轴，滑轮).
What is the formula for force?
🔹 问题: 力的计算公式是什么？
Force = Mass × Acceleration (力 = 质量 × 加速度).
How does an inclined plane help at the airport?
问题: 斜面如何在机场起作用？
Helps move luggage with less force. (减少移动行李所需的力).
Q: What simple machine makes moving heavy boxes up a truck easier?
🔹 问题: 哪种简单机械可以让重物更容易被搬上卡车？
An inclined plane (斜面).
Why is work not done when pushing against a wall?
🔹 问题: 为什么推墙时没有做功？
Because the wall does not move. (因为墙没有移动).
What is the difference between actual and ideal mechanical advantage?
问题: 实际机械优势和理想机械优势有什么不同？
Actual includes friction, ideal does not. (实际的考虑摩擦力，理想的没有).
If a machine increases the force applied but reduces speed, what is happening?
问题: 如果一台机器增加了施加的力但降低了速度，这说明什么？
The mechanical advantage is greater than 1. (机械优势大于 1).
Why do roller coasters use pulleys?
问题: 为什么过山车使用滑轮？
To pull the cars up the first hill. (把车拉上第一个坡).