Pushes and Pulls
What do we call any push or pull that makes an object move?
What is the invisible pulling force that keeps our feet on the ground and pulls objects down?
Gravity
What is the contact force that slows down moving objects and rubs against things to resist their motion?
Friction
What do we call a basic mechanical tool that takes a force we put into it and multiplies or changes it to make our work easier?
Simple Machine
What simple machine uses a wheel with a grooved rim and a rope to pull heavy weights upward, like a flag up a flagpole?
A pulley.
If you kick a soccer ball or push a grocery cart, are you using a push force or a pull force?
A push force (it moves the object away from you).
What do you call a force that acts on an object only when they are physically touching?
A contact force.
Which surface would create more friction if you tried to slide a heavy box across it: a smooth sheet of ice or rough pavement?
Rough pavement.
Which simple machine uses a straight board and a pivoting point called a "fulcrum" to help lift heavy loads?
A lever
What do we call a set of wheels with teeth that lock together to change the speed or power of a machine, like on a bicycle?
When you play a game of tug-of-war, which type of force is each team using to bring the other team closer to them?
A pull force
What do you call a force that can move an object from a distance without touching it, like gravity or magnetism?
A non-contact force (or external force).
What type of friction keeps an object completely still and prevents it from starting to move?
Static Friction
A ramp used to slide heavy boxes up into the back of a moving truck is an example of which simple machine?
A inclined plane.
What is the term for the ratio of the force produced by a machine compared to the force you put into it? (Hint: It measures how much help the machine gives you!)
Mechanical Advantage.
True or False: If an object moves, a force must have acted on it.
True
What invisible force can pull a metal paperclip toward a bar without even touching it?
Magnetic Force
What type of friction happens when an object uses round tires or rollers to move across a floor?
Rolling Friction
An axe blade or a heavy doorstop is shaped like two inclined planes put together. Which simple machine is this?
A wedge.
If you want to make the mechanical advantage of a screw stronger so it is easier to turn, should you design the spiral threads (pitch) closer together or wider apart?
Closer together (it will take more turns, but it will be much easier!).
If a person pushes a swinging child to move them away, what will happen if they do not apply enough pushing force?
The child won't move very far.
What special type of contact force happens when you squeeze or stretch an object, like a pogo stick or a trampoline?
Spring Force
Besides static friction and rolling friction, what is the third type of friction that happens when two flat surfaces rub past each other?
Sliding Friction
A jar lid and a light bulb use an inclined plane wrapped around a cylinder. What simple machine are they?
A screw.
A well uses a handle to spin a rod and lift a bucket of water. This mechanism is an example of which simple machine?
A wheel and axle.