Measuring Time and Distance
How do you measure the time and distance?
Time: Distance divided by speed
Distance: Time times speed
What's the formula for average speed?
Total distance/total time
A straight horizontal line on a distance–time graph means?
The object is not moving
What is the best equipment to measure time?
light gate
How do you know if something is travelling at a constant speed in a distance-time graph?
The slope will be a straight line.
The graph of a cyclist shows a steep line from 0–5 seconds and a less steep line from 5–10 seconds.
(a)During which time was the cyclist moving faster?
b) Why?
0-5 seconds
because it has a stepper slope
What is the X and Y axis for distance-time graph?
X is time; Y is distance
What's the difference between steep slope and gentle slope in a distance-time graph?
steep slope is faster speed, while gentle slope is slower.
A train travels 300 m in 30 seconds.
a) Calculate its speed.
b) If it continues at this speed, how far will it travel in 60 seconds?
10m/s
600m
Which result is anomalous,
12s,13s,14s,26s,16s
26s
Convert 54km/h to m/s.
15m/s
A curved graph becomes less steep over time.
a) What does this tell you about the object's speed?
b) Is the object accelerating or decelerating? Explain.
the speed is changing
it is decelerating because it became less steep
A man travelled 46m at a time of 5 minutes and 23 seconds, what's the speed in m/s
0.14m/s
How can you use two light gates to measure how long it takes a toy car to travel 50 cm?
The time will start when the car reach the first light gate and stops when it reaches the second light gate.
A distance–time graph is a straight line passing through (0,0) and (10,200).
a) What is the speed?
b) If the line continued, how far would the object travel in 25 s?
20
300