Speed!!

Learning Question• Would Usain Bolt the 100m record

holder, be able to outrun a cheetah?

http://news.bbc.co.uk/sport1/hi/athletics/8204381.stm

Distance, Time and Speed To work out the speed of an object you need to know: • the distance traveled• how long it took to travel that distance

Use this equation:

SPEED = distance

timeSpeed is measured in many

different units, e.g. m/s, km/h, km/s, miles per hour.

The units of distance and time used will give the units to be used

for speed.

d

s x t

Formula triangle

Formula triangle

Formula triangle

Distance (km) = Speed (km/h) x time (h)

= 3.6 km/h x 2 h = 7.2 km

Questions1. A group set off from home and walk at an average speed of 3.6 km/h. How far would they travel in 2 hours? Give your answer in km.

d

s x t

Click for solution

Would you survive a safari?Different animals run at different speeds, we are going to see if we would be able to beat them.

Elephant 11m/s

Zebra 18m/s

Cheetah 31m/s

Squirrel 5m/s

Pig 4.5m/s

0.013m/s

http://www.youtube.com/watch?v=4QZPXEhP_Sw

So would Usain Bolt be able to outrun a

cheetah?

Usain Bolt ran the 100m in

9.58 seconds! Could he

outrun the cheetah?

Cheetah’s Speed = 31m/s