chapter 8.1
Magnetic force:
Static electricticity acts on certain wraps and compounds, such as iron, nickel, and cobalt. Natural magnets, including earth, and electromagnets have a field around them that can expert pushing and pulling forces.
Tension force:
Tension force is experienced by a rope when it is pulled at either end. This is an example of contact forces.
What is the difference between a contact force and an action-at-a-distance force?
The difference between contact force and an action-at-a-distance force is that action at a distance force act on objects without touching them and contact forces have only an effect when they touch on object.
Unbalanced forces
Unbalanced forces are not equal in size and they do not have to act in opposite directions.
What is the difference between mass and weight?
Weight is the amount of force that gravity exerts on the mass of an object. The mass of an object measures the amount of matter in it.
Why is your weight different on different planets?
Your weight is different on different planets because the pull of gravity is different in each planet.
Action-at-a-distance forces
action-at-a-distance forces act on objects without touching them/.
what types of forces are there?
contact forces and action-at-a-distance object
Contact forces
contact forces have an effect only on objects that they touch.
How are forces measured?
force is measured in units called newtons.
Newton
A Newton is a small amount of force. It is approximately the amount you would have to exert to hold up a medium-sized apple.
what is a force?
A force is a pull or a push that acts on an object. An object can cause an object to move or change.
Milk:
A typical carton of milk requires 10 N to lift.
Balanced forces
Balanced forces are forces that are equal in size and act in opposite directions.
Elastic force:
Elastic force is exerted when a spring returns to its original shape after being stretched. This is an example of contact forces.
Friction:
Friction works to slow down or stop motion due to surfaces rubbing each other. This is an example of contact forces.
Gravitational force:
Gravitation pulls objects toward each other. A ball that is tossed in the air falls to the ground because of this force. This is an example of action-at-a-distance force.
Why does a balance scale work anywhere in the universe?
Gravity pulls equally on objects of equal mass, so it doesn't matter where you use a balance scale.
Battery:
It takes about 1 N to lift a D cell battery.
Electrostatic force:
Magnetic force pulls or pushes on metals and compounds such as iron, nickel, and cobalt.
3 things a force can do:
1. A force can set a motionless object in motion or make a moving object stop. 2. A force can make a moving object slow down, speed up, or change direction. 3. A force can change the shape of an object.
