Physics exam flashcards

Acceleration

Acceleration

Any change in velocity.

• Change in speed or direction

• Measured in m/s

Air resistance

A force that resists the motion of an object through air.

• Caused by a collision between an object and air molecules.

Applied Force

A type of force exerted by something.

*Example- A ball kicked by a person. (The person applies the force.)

Balanced Force

A force with an equal and opposite force acting on the same object.

Collision Force

A contact force that acts on an object when it hits another object.

• The collision forces on both objects are equal and opposite, and exist only so long as the objects are touching.

Contact Force

Any force that can only occur when two objects are touching.

• Contact forces include friction, air resistance and applied forces.

First law of motion (Law of inertia)

An object has a constant velocity unless acted on by a net force.

• An object will keep moving at the same speed in the same direction unless acted on by a net force (law of inertia).

Force

A push or pull.

• A force (F) causes an object to accelerate unless it's balanced by an equal and opposite force.

Free body diagram

A representation of all the forces acting on an object.

The object is represented as a box. The forces acting on it are drawn as arrows radiating from the box.

Friction

A force that resists an object's motion.

• Friction is a contact force. It is larger on rough or sticky surfaces.

Gravity

The attractive force between any two objects that have mass.

• The force of gravity depends on the sizes of the masses and the distance between them.

Inertia

The tendency to have a constant velocity unless acted on by a net force.

• Any object will stay at rest, or keep moving at the same velocity, unless acted on by a net force.

Mass

The amount of matter in an object.

Net Force

The overall force on an object.

• The net force is calculated by cancelling out any balanced forces and adding or subtracting the remaining forces.

Netwon

The standard unit of force.

• The newton (N) is named after Isaac Newton. 1 N is the force needed to give a mass of 1 kg an acceleration of 1 m/s/s.

Non-Contact Force

Any force that can occur even when two objects are not touching.

• Non-contact forces include gravity, magnetism and electrostatic forces.

Reaction Force

The force that is paired with another force by the third law of motion.

• The paired forces are of the same size and type, but acting on different objects in opposite directions.

Second Law of motion

Net force equals mass times acceleration.

• An object's acceleration is directly proportional to the net force acting on it, and inversely proportional to its mass.

Speed

The rate of change of an object's position.

Support Force

An upward force exerted on an object by a solid surface.

• The upward support force balances gravity and prevents an object from falling.

Tension.

A force that pulls inward when a solid object is stretched.

• Tension is a contact force that can prevent a stretched rope from breaking.

Third Law Of Motion

Every force has an equal and opposite reaction force.

• Forces always come in pairs of the same size and type, but acting on different objects in opposite directions.

Unbalanced Force

A force without an equal and opposite force acting on the same object.

• Unbalanced forces result in a net force that causes an object to accelerate.

Velocity

The speed of an object in a certain direction.

Water resistance

A force that resists an object's motion through water.

Weight

The force of gravity on an object.

Acceleration due to gravity

A change in velocity due to gravitational force.

• The gravity acting on Earth’s objects is 10m/s/s downward.

Ways to accelerate

1- Speed up

2- Slow down

3-Change direction

Displacement

The change in the position of an object.

• Measured from start point to end point.

Instantaneous Speed

How fast an object is moving at a single moment.

Kinematics

A branch of physics that describes motion.

• Described in terms of quantities such as velocity and acceleration.

Scalar Quantity

A quantity that has a size but not a direction.

• Includes mass and speed

Speed

The rate of change in an objects position.

Vector Quatity

A quantity that has both a size and direction.

• Includes velocity, acceleration and force

Velocity

The speed of an object in a certain direction.

Gravitational Potential energy

Energy an object has due to its position or height.

Potential energy

Is stored energy.

Its unit is joules (J)

The 4 types:

• Chemical

• Gravitational

• Elastic

• Nuclear

Elastic potential energy

Stored mechanical energy.

• Stored by the application of force.

Chemical potential energy

The energy stored in bonds between atoms that hold molecules together.

Nuclear potential energy

The energy stored in the nucleus of an atom that holds the nucleus together.

Kinetic energy

Has to do with motion.

Types (5):

• Mechanical

• Heat

• Light

• Sound

• Electrical

Mechanical kinetic energy

Movement of objects or substances from one place to another.

Heat kinetic energy

The internal energy of a substance from the vibrations of an atom/molecule that make up the substance

Light Kinetic energy

Travels in transverse waves

Sound kinetic energy

The movement of energy through substances in the form of compression waves.

Electrical kinetic energy

The energy from the flow of electrical charge.
- The movement of electrons in one direction.

Law of conservation of energy

Energy can never be created or destroyed but only transferred or transformed

Total energy

Kinetic energy + Potential energy= total energy