3.1

Question 1

Measuring g PAG

Answer 1

Electromagnet in a circuit supports a steel ball.
The circuit is broken: current stops: electromagnet turns off and drops ball.
The ball falls as a timer is started.
Ball falls onto trapdoor and stops timer.
Distance fallen and time taken recorded, repeated for different heights.
Plotted, gradient is g/2

Question 2

Uncertainty factors in g PAG

Answer 2

If the electromagnet current is too high there will be a delay in the release of the ball. Current should only just support ball.
Too large a distance fallen or ball too small: air resistance can have a noticeable effect.
Accurately measure distance of fall, consistent position on ball

Question 3

Stopping distance
Thinking distance
Breaking distance

Answer 3

Stopping distance is sum of the thinking and breaking distance: total distance travelled while stopping.
Distance travelled between seeing hazard and pressing breaks
Distance travelled while decelerating and applying breaks

Question 4

Factors that increase thinking distance

Answer 4

Higher speed
Tiredness
Alcohol and drugs
Distractions
Age

Question 5

Factors effecting braking distance

Answer 5

Higher speed
Poor road conditions (icy/wet)
Poor conditions of brakes
Poor conditions of tyres
Mass of car