Physics double award

verage speed =

distance / time

v = d / t

Standard Unit for mass (m)

kilogram

(kg)

Standard Unit for distance (d) or displacement (s)

metre

(m)

Standard Unit for speed (s) or velocity (v)

metre/second

(m/s)

Standard Unit for acceleration (a)

metre/second²

(m/s²)

Standard Unit for Force (F)

Newton

(N)

Standard Unit for time (t)

Second

(s)

Standard Unit for gravitational field strength (g)

Newton/kilogram

(N/kg)

What does the gradient of a distance-time graph represent?

Gradient or the slope gives the speed.

Flat line means stationary, straight line means constant speed, curved line means accelerating

Acceleration =

Change in velocity/time taken

a = (v-u) / t

What does the gradient of a velocity-time graph represent?

What does the area underneath the line represent?

gradient = acceleration

flat line = constant velocity

straight lines = constant acceleration (changing velocity)

area under graph = distance travelled

(final speed)² =

(initial speed)² + (2 x acceleration x distance)

v² = u² + (2 x a x s)

(This equation is given to you)

A force can change an objects….

• speed

• shape

• direction

Types of force….

Gravitational (Weight)

Electrostatic

Magnetic

Friction

Air Resistance (Drag)

Upthrust (from fluids)

Reaction (from solids)

Engine force

(and more…)

What is Scalar?

Give some examples

A measurement with just magnitude.

Time, distance, temperature, mass, energy, charge, area, volume, frequency etc.

What is a Vector?

Give some examples

A measurement with magnitude and direction.

Velocity, acceleration, force, weight, momentum, etc.

There is an unbalanced force

when 2 or more forces acting on an object are uneven

Resultant Force is…..

The combination of all forces acting on an object.

Newton's 2nd Law: Force =

mass x acceleration

F = m x a

Newton's 2nd Law: Acceleration

force / mass

a = F / m

Newton's 2nd law: Mass

force / acceleration

m = F / a

Weight =

mass x gravitational field strength

W = m x g

Friction and Air Resistance act in what direction?

The direction that opposes motion (e.g. if an object is falling then air resistance is acting upwards)

Stopping Distance =

Thinking Distance + Braking Distance.

It is the total distance for the car to come to a complete stop

What is Thinking Distance? What factors affect it?

The distance taken for the driver to react and apply the brakes.

• Tiredness, Alcohol or drugs, Distractions, Age, Poor Visibility (e.g. fog), Reaction Time

What is Braking Distance? What factors affect it?

The distance traveled while the braking force stops the car.

• Speed, Condition of the tires and brakes, Condition of the road surface (including weather conditions such as ice or water on the road), Mass of the vehicle

What is Terminal Velocity? What is the Resultant force on an object traveling at Terminal Velocity? What forces are acting on an object falling at Terminal Velocity?

Where an object reaches a maximum constant velocity. The forces on the object are balanced and so the resultant force is Zero Newtons.

As an object falls, its weight causes it to accelerate. As it gets faster, the air resistance increases until it balances the weight of the object. At this point the forces are balanced and it no longer accelerates.

Describe how to investigate how the extension of an object, such as a spring, varies with applied force.

• Clamp a spring onto a stand, such that it is hanging vertically down.

• Measure the spring's original length.

• Place a known weight (100g = 1N) on to the end of the spring and measure how far it has extended. A pointer attached to the spring (fiducial marker) can help to reduce parallax errors.

• Repeat the process by adding one weight at a time and measuring the extended length each time.

• Calculate the extension for each weight (Extension = extended length - original length)

• Plot a graph of force against extension

• Draw a line of best fit. It should be a straight line through the origin. If it is, then the extension is proportional to the applied force, and the spring is said to obey Hooke's law.

• The Spring Constant can be calculated by dividing the change in Force by the extension.

Hooke's law says…

the extension of a spring (or other material) is proportional to the force applied to it

What is elastic behaviour?

The ability of a material to recover its original shape after the forces causing deformation have been removed.

Unit of Current (I)

Amp or Ampere (A)

Unit of Charge (Q)

Coulomb (C)

Unit of Energy (E)

Joule (J)

Unit of Resistance (R)

Ohm (Ω)

Unit of Voltage (V)

Volt (V)

Unit of Power (P)

Watt (W)

What is double insulation?

many electrical appliances have casing made from an insulator such as plastic, rather than metal. The electrical parts parts of the device cannot therefore be touched. The appliance is said to have double insulation. Such appliances will only have two-wire cables as they don't need the earth wire

What is a circuit breaker?

What is its advantage over a fuse?

a switch that opens and stops the current flowing in a circuit when the current is too high.

Sometimes called a Residual Current Circuit Breaker (RCCB).

It does not need replacing like a fuse does, it just needs resetting.

What is the role of an Earth Wire?

To carry away electrical current or discharge and object to make the user safe, and to protect the appliance.

They are found in appliances with metal casing.

Draw the symbol for a fuse.

What does a Fuse do?

If the normal operating current of an appliance is 3.5A, which fuse would you need, 3A, 5A, or 13A

It breaks the circuit by melting when the current is too high.

5A

What does the Live Wire do?

Carries the current to the appliance

What does a Cable Grip do?

Stops the cable and wires from being pulled out of the plug

What does the Neutral Wire do?

Completes the circuit and carries away current

Electrical Power =

Current x Voltage

P = I x V

Electrical Energy Transferred =

Current x Voltage x time

E = I x V x t

(this equation is given to you)