Physics Section 1 Revision

• Vector quantities have a magnitude (size) and a direction.

• Vector Quantities = Force, Velocity, Displacement, Weight, Acceleration, Momentum, etc.

• Scalar quantities have only a magnitude (size).

• Scalar Quantities = Speed, Distance, Mass, Energy, Temperature, Time, etc.

• Distance is just how far a object has moved, it is a Scalar Quantity so it does not involve direction.
• Displacement is a Vector Quantity as it measures the direction as well as the distance in a straight line from an objects starting point to its finishing point.
• For example if you walk 5m North and the 5m South, your displacement is 0m because you're back where you started but your distance travelled is 10m.

• Speed and Velocity both measure how fast you're going, but Speed is Scalar and Velocity is a Vector.
• Speed is just how fast you're going with no regard to the direction; however, Velocity is speed in a given direction.
• This means you can have an object going a constant Speed with a changing Velocity. This happens when the object is changing direction but staying at the same speed.

Distance travelled (m) = Speed (m/s) x Time (s)

Speed (m/s) = Distance travelled (m) ÷ Time (s)

Time (s) = Distance travelled (m) ÷ Speed (m/s)

Revision Questions:

1) Name 2 examples of

a) Scalar Quantities

b) Vector Quantities

2) A sprinter runs 200m in 25 seconds.

What is his average speed?

Revision Answers

Question 1)

a) any two of the following; speed, distance, mass, energy, temperature, time

b) any two of the following; force, velocity, displacement, weight, acceleration, momentum.

Question 2)

200m ÷ 25s

= 8m/s