A force is a push or a pull that acts on an object.
A force can cause an object to move or change.
- set a motionless object in motion or make a moving object stop.
- make a moving object slow down,speed up, or change direction.
- change the shape of an object.
What types of forces are there?
You can group forces into two main types.
- contact force- effect only on objects that they touch.
friction works to slow down or stop motion due to surfaces rubbing against each other.
Tension force is experienced by a rope when it is pulled at either end.
Elastic force is exerted when a spring returns to its normal shape after being stretched.
- action at a distance force-acts on object without touching them.
Gravitation pulls objects toward to each other.
Magnetic force pulls or pushes on metals compounds such as iron .
Static electricity ,such as in lightning, causes pushing and pulling forces.
How are forces measured?
force is measured in units called newtons.
The newton is related to the weight of an object.
Weight is the amount of force that gravity exerts on the mass of an object.
The weight is not the same as mass.
the mass of an object measures the amount of matter in it.
The weight of an object measures how strongly gravity pulls on that amounts of matter.
Gravity pulls more strongly on objects that have more mass.
What happens to forces are balanced and unbalanced?
Balanced forces are forces that are equal in size and act in opposite directions.
Unbalanced force are not equal in size, they do not have to act in opposite directions.
