Section 1 - Motion, Forces and Conservation of Energy
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What are vectors?
Quantities with both magnitude and direction.
What are scalars?
Quantities with magnitude only.
What are some examples of vector quantities?
Force, velocity, displacement, weight, acceleration and momentum.
What are some examples of scalar quantities?
Speed, distance, mass, energy, temperature and time.
What is a distance, in physics, defined as?
How far an object has moved.
What is displacement, in physics, defined as?
The distance and direction in a straight line from an object’s starting point to it’s finishing point.
What is speed, in physics, defined as?
Speed is a measure of how fast something is going.
What is velocity, in physics, defined as?
How fast something is going and in what direction.
Describe the formula relating (average) speed & time.
d=s×t d = distance s = (average) speed t = time
What is acceleration, in physics, defined as?
The change in velocity over a certain amount of time.
What is uniform acceleration, in physics, defined as?
Speeding up (or slowing down) at a constant rate.
Describe the formula relating acceleration, time and change in velocity.
a=(v-u)/t a = acceleration v = final velocity u = initial velocity t = time
Describe the formula for constant acceleration.
v²-u²=2×a×x v = final velocity u = initial velocity a = acceleration x = distance
Which graph shows how far something has traveled?
Distance/Time graphs.
Which graph can have both positive and negative gradients?
Velocity/Time graphs.
In a distance/time graph, how can speed be worked out?
Speed = gradient = change in y / change in x
In a velocity/time graph, how is distance worked out?
By calculating the area under the graph.
What is Isaac Newton’s first law?
Every object persists in its state of rest or uniform motion in a straight line unless it is compelled to change that state by forces impressed on it. Or a still object will not move unless forced to, and a moving object will not stop or change direction unless forced to.
Describe the equation relating resultant force and acceleration.
F=m×a F = resultant force m = mass a = acceleration
List some safety features used in cars.
Seat belts, air bags and crumple zones.
What is mass, in physics, defined as?
The amount of ‘stuff’ in an object.
What is weight, in physics, defined as?
Mass with gravity.
Describe the equation for weight.
W=m×g W = weight m = mass g = gravitational field strength
What is Isaac Newton’s second law?
Force is equal to the change in momentum per change in time. For a constant mass, force equals mass times acceleration.