Forces

Question 1

Friction

Answer 1

Friction is a force that resists movement. It slows a ball down until eventually stops. Friction comes from the rubbing of two surfaces, which cause resistance. Because of this, there must be a force that is greater than friction to be able to move. Your pedalling force must be greater than the force of friction.

Question 2

How do we reduce friction?

Answer 2

We can reduce friction by using LUBRICATION. Lubrication is using a lubricant, like oil or grease, to make a surface slippery. Making a surface slippery reduces the friction of the surface, making movement faster. We can also use STREAMLINING, making a surface smooth in order to cause a smooth flow and therefore less friction.

Question 3

The 6 impacts of forces

Answer 3

They are:

Begins to move
Speeds up
Slows down or stops moving
Changes direction of motion
Changes shape
Remains still

Question 4

Hydraulics

Answer 4

Hydraulics is the process of water running in high-pressure tubing in order to build force and function a machine. It is mainly used in machinery.

Question 5

Mechanical Advantage

Answer 5

Mechanical Advantage = load ÷ effort.

Question 6

Gears

Answer 6

Gears, or cogs, are wheels with “teeth” that rotate in order for the surrounding wheels to rotate as well. Touching wheels will always turn the opposite direction to each other. The first gear is called the “driver” and “drives the other gears. Smaller gears will always rotate faster than larger gears.

Question 7

Balanced forces

Answer 7

If forces are balanced, then an object remains still. If you are leaning back holding on to someone who is also leaning back, and the pull of your partner and the pull of gravity are equal, then you will remain still. If one is greater, they will pull you. The stronger force will always pull/push.

Question 8

Simple machines

Answer 8

A machine is any object that makes work easier.

There are different types of machines. Here they are:

Ramps: Used to lift things in order for them to be elevated. It is used to lessen the effort required to push the object.

Wedges: A wedge is an inclined plane that changes the force pulling downwards into a force pulling sideways. It can be used to maximise the force exerted upon an object.

Screws: A screw is used as an effort-minimiser. It lessens the effort required to move the object (like a cork) and is similar to a ramp. It is operated by pushing it into the object using turning force and the screw turns to move the object.

Wheels and axles: A wheel is a circle which turns on itself about the fulcrum, or turning point. When a wheel rotates, it activates the axle which also rotates. When a wheel is used with an axle, it can be used as a force maximiser, which multiplies the force exerted unto the object. An example can be a door knob.

Levers: Levers are used to reduce the effort required to move an object. A can opener is an example of one. There are three types of levers, first class, second class and third class. The different classes depend on where each component of the lever is.