WHAT IS AVERAGE SPEED
The speed throughout a journey. The total distance travelled divided by the time taken
EXPERIMENT TO MEASURE AVERAGE SPEED
- Measure the distance between light gates.
- Let trolley role down the slope.
- QED timer records time to travel between light gates.
- Calculate average speed with distance between the timers.
WHAT IS INSTANEOUS SPEED
The speed at a particular point. Length of card on trolley divided by the time the card took to pass the light gate
EXPERIMENT TO MEASURE INSTANTANEOUS SPEED
- Place light gate in the middle of the ramp.
- Measure the length of the card in metres.
- Roll trolley down the ramp so it cuts light beam.
- Record interval for mask to cut the light beam.
- Calculate instantaneous speed.
WHAT IS A SCALAR
a Scalar quantity is defined by magnitude (something with a size)
WHAT IS A VECTOR
Has a size and direction
SCALAR EXAMPLES
Speed, time, energy, mass, distance, temperature
EXAMPLES OF VECTORS
Force, Acceleration, Velocity, Weight, displacement
WHAT IS DISTANCE AND DISPLACEMENT
Distance (scalar) - how far something has travelled.
Displacement (vector) - how far something is from its starting point.
WHAT IS SPEED AND VELOCITY
Speed (scalar) - How much distance am object has travelled in a certain time. v=d/t
Velocity (vector) - Displacement of an object in a certain time. (needs a direction). v=s/t
WHAT DOES A VELOCITY TIME GRAPH SHOW
Size, direction
positive and negative show a change in in direction.
HOW DO YOU FIND THE DISPLACEMENT OF AN OBJECT ON A VELOCITY TIME GRAPH
D = AreaUnderGraph
HOW DO YOU FIND THE DISTANCE TRAVELLED ON A SPEED TIME GRAPH
D = AreaUnderGraph
WHAT IS ACCELERATION
The change in velocity (ms^-2)
HOW DO YOU FIND ACCELERATION FROM A VELOCITY TIME GRAPH
The gradient
EXPERIMENT TO CALCULATE ACCELERATION
- When trolley passes light gate A, use width of mask and time to pass to calculate initial velocity.
- Do the same at light gate B
- Measure the time to travel between both light gates
WHAT IS NEWTON’S FIRST LAW
“An object will remain at rest or move at constant speed in a straight line unless acted on by an unbalanced force”.
WHAT CAN FRICTION DO
Oppose the motion of an object
WHAT IS NEWTON’S SECOND LAW
“If you keep the unbalanced force constant and double the mass, you have the acceleration”. Balanced forces means constant velocity. If unbalanced forces act on an object, the object accelerates.
WHAT IS MASS AND WEIGHT
Mass (scalar) - the quantity of matter forming an object and remains constant anywhere.
Weight (vector) - It is a force and is the earths pull on an objects.
WHAT IS GRAVITATIONAL FEILD STRENGTH
The weight per unit mass. The weight of an object is caused by the pull of gravity. Gravity pulls more or less in different places.
WHAT IS NEWTONS 3d LAW
“If A exerts a force on B, B will exert an opposite but equal force on A”.
HOW DOES A ROCKET FOLLOW NEWTON’s THIRd LAw
A rocket is pushed forwards because the propellant is pushed back, making the rocket accelerate
WHAT IS TERMINAL VELOCITY
Terminal velocity is the maximum constant velocity that a falling object can reach
Downwards gravitational force = upwards friction
