Calculating Speed Flashcards

All 6 cards in this deck

What is the equation linking distance travelled, speed and time?

$distance = speed \times time$, or $s = vt$

In the equation $s = vt$, what does each symbol stand for and what is its unit?

$s$ = distance travelled in metres (m), $v$ = speed in metres per second (m/s), $t$ = time in seconds (s).

What are the steps to calculate the time taken for a journey from distance and speed?

e.g. travelling 1500 m at 20 m/s

1. Write $s = vt$
2. Rearrange: $t = s \div v$
3. $t = 1500 \div 20 = 75$ s

How do you calculate average speed for non-uniform motion?

e.g. a car travels 300 m in 3 s, then 200 m in 7 s

Total distance ÷ total time = $500 \div 10 = 50$ m/s.

What must you do with a distance given in km before using $s = vt$ with a speed in m/s?

Convert it to metres by multiplying by 1000.
e.g. 1.5 km = 1500 m

True or false? If a car covers 1000 m in 50 s, it must have been travelling at 20 m/s the whole way.

False. 20 m/s is its average speed; its actual speed may have varied.