Give one example of a screw.
Teacher decide. Possible answer: screw.
Explain the trade-off for an inclined plane.
Distance travelled traded for force to lift/lower a weight.
Why would driving a car with no wheels be difficult.
Too much friction.
Where do you see wheel and axel?
Wheels of a car, for example.
What is 滑轮 in English called?
Pulley
Give an example of an inclined plane.
Teacher decide. Possible answer: ramp
Explain the trade-off in a lever.
Force used to spin a lever vs the distance from the point of contact to the fulcrum.
What is the fulcrum of the person in our magic trick?
Foot.
What can you use a pulley to do?
Lift heavy objects.
What is 投石器 in English?
Catapult.
Give one example of a wedge.
Teacher decide. Possible answer: knife
Explain the trade-off in a screw.
Force required to put a screw in an object vs the time (caused by distance to spin) required to screw it in.
Where is the fulcrum of the lever in the catapult?
Under the orange rubber band.
Inclined plane.
What is a fulcrum?
The point that doesn't move on a lever. The center or revolution.
Which simple machine is this?
Lever
Explain the trade-off in a pulley.
To use lesser force, you need to pull for a longer distance.
How does the magic trick work?
Teacher decides.
Simply put, the direction of force is changed. To not spin, aim at the foot.
Which two simple machines are included?
Lever and Wheel and Axel
What does trade-off mean?
A balance between two desirable things. 权衡
What simple machine is this?
Lever
Explain the trade-off in a wedge.
To pull something apart very far, you need to push the wedge a long distance.
How does a simple single pulley save you energy when lifting something?
Your own gravity works in your favour, rather than against you when lifting.
Which two simple machines are included in a scissor?
Lever and Wedge
What is mechanical advantage?
机械优势