Balanced and Unbalanced Forces Notes What is a force?

A _______________________ is a push or a pull that acts on an object

- units are in Newtons (N) - forces can make an object move or change direction - forces can act in 2 ways

o through direct contact ! ________________________ involve direct contact with an object ! ________________________ is a force that opposed the motion between two

surfaces that are in contact • you need more force to overcome friction to get the object moving

o at a distance ! __________________ is the universal attraction that exists between all objects

• pulls towards center of the Earth • the pull gives the object its _______________ (a measure of the amount

of gravity acting on an object) ! ____________________

What is net force? ____________________ is the combination of all the forces acting on the object

- can be o ________________________ - a set of forces that cancel each other so that there is no

overall force on an object ! act in opposite directions ! motion of the object doesn’t change

o ________________________ - set of forces acting on an object that do not cancel each other out

! motion of the object changes ! can make an object

• start moving • speed up • slow down • change direction

Calculating net force - when two forces are in ________________________________, the smaller force is subtracted

from the larger force

- when the two forces are ________________________, the net force is zero

- when two forces are in __________________________________, the forces are added together

How do balanced and unbalanced forces affect motion?

- Balanced forces o Result in _____________________________ o Net force = zero o Speed or direction doesn’t change o Acceleration = zero

- Unbalanced forces o Object will _________________________ and _____________________ will change o Because speed changes, acceleration changes

How to calculate force

Example: If an object has a mass of 6 kg and an acceleration of 1.2 m/s2, what is the net force acting on the object?

Example: A team of dogs pulls a full sled with a net force of 1500 N. The sled has a mass of 900 kg. What is the acceleration of the sled?

Example: A second team of dogs is pulling a sled with a net force of 2000 N. The sled is accelerating at 2.2 m/s2. What is the mass of a sled?