10SCI3 - Physics

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SI Units

Meter, M, Length

Kilogram, Kg, Mass

Second, S, Time

Conversion Multiples

Scalar VS Vector

Scalar:

Physical quantities that only have a magnitude (size), can be measured with a number

Vector:

Have magnitude and direction

Can be represented using arrows

Resultant Vectors

Single Vector that has the same effect as two or more vectors combined

Rules of Drawing Vectors:

• Always use a scale (e.g., 1 cm = 5 N)

• Draw head-to-tail:

  • Start each vector at the head of the previous one

• Label magnitude + unit on each vector

• Label direction (compass, angle, or N/E/S/W)

Rules of Resultant Vectors:

• Always goes from start of first vector to end of last vector

• Label as R (or “Resultant”)

• Include magnitude + direction

Distance Vs Displacement

Distance: Overall change of position

Displacement: Has direction so its a VECTOR. The change from where it start to where it ended. Straight from one place to another.

Speed

The rate at which something moves.

Units: m/s

The rate of distance with respect to time

Scalar, only have MAGNITUDE

Velocity

Speed with DIRECTION

Units: m-s^-1

The rate of displacement with respect to time

Vector, has magnitude and direction

Speed pairs with:

Velocity pairs with:

—> Distance

—> Displacement

Acceleration

The rate of change of velocity with respect to time.

Acceleration is a vector.

Displacement Time Graph

Velocity Time Graph

When an objects velocity is getting, higher, higher and higher, the object is accelerating.

To calculate the displacement/distance of a velocity graph:

Calculate the area, break up the graph into little pieces.

Distance: Add all numbers up

Displacement: Add numbers up with NEGATIVES and POSITIVES

Velocity at REST, STOP, BEFORE DROPPING.

v = 0m-s^-1

Energy is SCALAR or VECTOR?

Energy is a scalar.

The conservation of mechanical energy:

The conservation of mechanical energy principle states that the total mechanical energy (kinetic + potential) of a system remains constant if only conservative forces (like gravity) do work.

IN AN ISOLATED SYSTEM.

Conversion from km/h to m/sec

Divide by 3.6

when the car has accelerated in the same direction

the car has accelerated

when the car has accelerated in the opposite direction

the car has decelerated

Different between Velocity Graph vs Displacement Graph

The fundamental difference is that a Displacement-Time Graph shows where an object is located relative to its starting point over time, whereas a Velocity-Time Graph shows how fast and in what direction that object is traveling over time

What is a force?

A force is a push or pull that can cause an object to change its speed, direction, or shape. The standard International System of Units (SI) for force is the newton

Inertia

Factor effecting inertia.

Is the natural tendency of an object to resist a change in its state of motion.

when you take all the forces away, inertia is what remains.

The sole factor that determines inertia is an object's mass. The heavier the object, the greater its mass and the more force required to change its state of motion.

Newton 1st Law (Law of inertia)

Objects at rest will stay at rest and objects in motion will stay in motion at the same velocity until an unbalanced force acts upon it.

Newtons second law (Law of acceleration)

Weight

Is the gravitational force acting on an object and it is measured in newtons.

If you weighed 40kg and was on earth, your weight would be 40kg * 9.8.

Mass vs Weight

Mass is the amount of matter in an object and remains constant anywhere in the universe. Weight is the gravitational force acting on that mass and changes depending on location

Newtons Third Law (Action - Reacton)

Newton's third law states that for every force applied in nature, there is an equal and opposite reaction. When one object exerts a force on a second, the second object instantly exerts an equal and opposite force back on the first.

Free body Diagram

-you cannot see the object and its enviorment

-in a free body diagram the arrows point away

Normal Force

The force that is always acting perpendicular to the surface, prevents it from falling over.

Work

Work is the transfer of energy to or from an object by applying a force that causes the object to move

Energy

Can energy be seen?

the ability to do work, measured in Joules.

Energy cannot be seen, but only detected when a change occurs.

Potential Energy

(Examples)

Elastic energy

nuclear energy

gravitational energy

chemical energy

Kinetic Energy

Examples

Thermal energy

Light energy

Sound energy

Eletrical energy

Energy Transfer vs Energy Transformation.

Energy transfer is the movement of energy from one location or object to another while retaining its original form, whereas energy transformation is the actual conversion of energy from one type into a completely different form.

Kinetic Energy

The energy an object has due to its motion.

Formula: Ek = 1/2mv²

Potential Energy

The energy an object has because of its position in a gravitational field.

E_p=mgh

Law of Conservation of Energy

The law of conservation of energy states that energy cannot be created or destroyed. It can only be transformed or transferred from one form to another. This means the total energy in an isolated system remains constant over time

Conservation of Mechanical Energy (Roller Coaster example)

Mechanical Energy Formula

Mechanical Energy = Gravitational Energy + Kinetic Energy

Mechanical Energy (A) = Mechanical Energy (B)

If the potential energy of this ball is 97Joules, and it is not moving at this point.

What is the mechanical energy?

97 Joules.

Remember in a system, the total amount of mechanical energy stays the same no matter what point.

This point the ball is not moving, so kinetic energy is 0, so the only force left is the potential energy.

Mechanical Energy

The mechanical energy of an object within an isolated system is conserved.

If the net force is zero

There will be no motion

If the net force is not zero

There will be acceleration

Does mass effect falling time?

(Ignoring air resistance)

No mass does not effect falling time.

Power

The rate at which energy is transferred or work is done.

It is measured in Watts

Power (formula)

W = work done

t = time

P = W/t

Energy Efficiency

Useful work / Wasted work

(In decimal or a percentage)

Sankey Diagram