Science Rev

Science Terms Reviewer
Lesson 1: Terms
Scalar Quantity - Has only magnitude. ( No direction )
Ex. Length, Area, Speed, Mass, Density, Pressure, Temp, Energy, Power, Work.
Vector Quantity - Has magnitude and direction

Ex. Displacement, Velocity, Acceleration, momentum, force, weight, lift, drag
Resultant vector is a combination, or, in simpler words, can be defined as the sum of two or more
vectors which has own magnitude and direction.
Resultant vector is a vector that gives the combined effect of all the vectors. When we add two or
more vectors, the outcome is the resultant vector.
Projectile motion - A form of motion in which an object or particle is thrown near the earth's
surface, and it moves along a curved path under the action of gravity only.
Projectile – an object in projectile motion

Trajectory – path that the projectile follows
Peak – highest point that the projectile could reach during its motion.
Range – the horizontal displacement of the projectile from its initial position in which its vertical
displacement is zero.
Parabola – shape of the path of a projectile.
(An example of a two-dimensional motion is projectile motion)
Types of Projectile Motion:
Horizontal
❑ Motion of a ball rolling freely along a level surface
❑ Horizontal velocity is ALWAYS constant
Vertical
❑Motion of a freely falling object
❑Force due to gravity
❑ Vertical component of velocity changes with time
Parabolic
❑ Path traced by an object accelerating only in the vertical direction while moving at constant
horizontal velocity
Momentum
● It is the product of the mass and velocity of a moving object.
● It is the measure of an object’s inertia in motion.
● It also tells how difficult it is to stop a moving object.
● •SI unit is kg • m/s
● The momentum of a moving object is defined by the equation;
If an object is at rest, it has no momentum. - no matter how large the mass.

Momentum is not the same as inertia.
Impulse
An impulse causes a momentum change
Impulse = momentum charge
Impulse, like momentum, is a vector quantity.
- The net force acting on an object is equal to the rate of change in an object’s momentum
over time, then the change in the object’s momentum can be calculated using:
● The direction of impulse is the same as the direction of the net force applied.
● SI unit for impulse is N • s or can be expressed as kg • m/s, which is same unit as

momentum.
Impulse-Momentum Theorem
Impulse affects the momentum of a moving object. To change the momentum, force is applied.
Another factor that affects the change in momentum is time – how long the given force is
applied. The greater the impulse imparted to an object, the greater its change in momentum,
that is.
This equation is known as the Impulse-Momentum Theorem. It states that: The change in the
momentum of an object during a given time interval equals the impulse of the net force that acts
on the object during the given time interval.
How can we change the Momentum of an object?
Increasing Momentum– in order to increase the change in momentum, you must increase the
magnitude of force and increase the time of contact with the object.
- Decreasing Momentum over a short period of time
- Increasing Momentum over a long period of time
CONSERVATION OF MOMENTUM:
A scientific principle that states that the total momentum of a system, or group of objects,
remains constant if no external forces act upon it.•This principle applies to objects in motion.
● It is closely related to Newton's Third Law of Motion which states that for every action,
there is an equal and opposite reaction.
CONSERVATION OF MOMENTUM IN ONE DIRECTION

When two objects interact in a single direction, the total momentum of the two objects before the
interaction is equal to the total momentum after the interaction.
CONSERVATION OF MOMENTUM IN TWO DIRECTIONS

If two objects interact in two perpendicular directions, the total momentum of the two objects
before the interaction is the same as the total momentum after the interaction in both directions.
Collision - It also shows one of the fundamental laws in physics – the law of conservation of
momentum.Total Momentum before Collision = Total Momentum after Collision.
Elastic Collisions: Elastic Collisions occur when objects strike each other and no deformation
occurs. Kinetic energy and momentum is conserved. A good example of this is seen between
billiard ball collisions.
Inelastic Collisions: Inelastic collisions occur when objects strike each other and stick together.
Momentum is conserved,
Science but kinetic energy is not conserved since deformation occurs between
Terms Reviewer
the objects and energy is lost in this process.
Lesson 4.3
Work - Represents a measurable change in a system caused by a force.
- Defined as a force acting upon an object to cause displacement.
- Mathematically (work = Force x Displacement Cos θ.)
- SI unit is Joule (J) or kg x m2/s2
Power - Defined as this rate of transfer.

- Is simply energy exchanges per unit time, or how fast you get work done.
- Watts = Joules/sec
- One horsepower 745.7W
Energy - Is the ability to do work
Work is the energy transferred to or from a system by a force that acts on it.
Kinetic Energy - Is the energy of motion
Potential Energy - An obj. Can store energy as the result of its position or elastic source.
Kinetic energy is a scalar. The kinetic energy of an object is completely describes by the magnitude alone.
The units are the same as for work ( Joule/J)
Gravitational Potential Energy - associated w/ an object at a given location above the surface of the earth.
Conservation of energy - The sum of kinetic energy and potential energy in a system is constant, in the
absence of friction.
Energy cannot be created or destroyed; it may be transformed from one form to another, but the total amount
of energy in a system remains constant.
Radiation - is energy that moves from one place to another in a form that can be described as waves or
particles. We are exposed to radiation in our everyday life. Some of the most familiar sources of radiation
include the sun, microwave ovens in our kitchens and the radios we listen to in our cars.
Convection - is the movement of particles through a substance, transporting their heat energy from hotter
areas to cooler areas.
Conduction - is the process by which heat energy is transmitted through collisions between neighboring
atoms or molecules.
Transformer - is a device that transfers electric energy from one alternating-current circuit to one or more
other circuits, either increasing (stepping up) or reducing (stepping down) the voltage.
Generator - Electric generator also known as dynamos is an electric machine that converts mechanical
energy into electrical energy.
Efficiency - is the ratio of the work performed by a machine to the total energy expended or heat consumed.
Thermodynamics - in physics is a branch that deals with heat, work and temperature, and their relation to
energy, radiation and physical properties of matter.
Radiator - is a heat exchanger used to transfer thermal energy from one medium to another for the purpose of
cooling and heating.

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Science Terms Reviewer

Vector Quantity - Has magnitude and direction

Projectile – an object in projectile motion

(An example of a two-dimensional motion is projectile motion)

Types of Projectile Motion:

If an object is at rest, it has no momentum. - no matter how large the mass.

● SI unit for impulse is N • s or can be expressed as kg • m/s, which is same unit as

How can we change the Momentum of an object?

- Decreasing Momentum over a short period of time

- Increasing Momentum over a long period of time

CONSERVATION OF MOMENTUM IN ONE DIRECTION

CONSERVATION OF MOMENTUM IN TWO DIRECTIONS

Power - Defined as this rate of transfer.

Energy - Is the ability to do work

Kinetic Energy - Is the energy of motion

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