Unit 03: Investigating Force and Motion

Acceleration

• the rate at which an object changes its velocity

• the speed of an object in a straight line

• the distance covered by an object in a given time

• the force applied to an object

Applied force

• force that is applied on an object by a person or another object

• force that resists the motion of an object

• force that acts at a distance without contact

• force that is always equal and opposite to another force

Balanced forces

• equal and opposite forces on an object that result in no change in position, direction, or motion; combined net force equals zero

• forces that cause an object to accelerate in the direction of the net force

• forces that are unequal and cause a change in motion

• forces that act on an object but do not affect its motion

Force

• a push or pull that can change the position or motion of an object / material

• a type of energy that can be stored

• a measure of the mass of an object

• a reaction to an external stimulus

Mass

• a measurement of the amount of matter in a sample

• a measure of the weight of an object

• the volume occupied by an object

• the density of a substance

Newton's 3rd law

• For every action, there is an equal and opposite reaction

• Force equals mass times acceleration

• Energy cannot be created or destroyed

• Objects in motion stay in motion unless acted upon

Newton's 2nd law

• When an object that has a constant mass is acted upon by a force, the object will accelerate in the same direction as the force applied.

• For every action, there is an equal and opposite reaction.

• The acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass.

• An object in motion stays in motion unless acted upon by an external force.

Unbalanced forces

• equal forces acting on an object that do not change its motion

• unequal forces acting on an object that may result in a change in position, direction, or motion; combined net force does not equal zero (greater than zero)

• forces that are balanced and result in no change in motion

• forces that act in the same direction and increase the object's speed

Simultaneous force pairs

• forces that occur in opposite directions and equal strengths at the point of contact between objects

• forces that act in the same direction and unequal strengths

• forces that are applied at different times

• forces that are always equal and opposite but not at the point of contact

Net force

• measurement of the total forces exerted on an object, measured in Newtons (N)

• the force applied to an object in the opposite direction

• the sum of all forces acting on an object, measured in pounds (lb)

• the force that causes an object to accelerate in a circular path