03/05/23 Measuring Average Speeds

Method

Collect a metre stick and a stopwatch.Mark out and measure a distance and time how long it takes to cover this distance.

COPY

Groups of 2 or 3.

Results

transport method

Distance(m)

Time(s)

Average Speed(m/s)

WalkingSprinting

3 Legged(optiona

l)Hopping

Blind Walk

• Average Speed tells us how much distance is covered in a certain time.

• To measure average speed we need to measure– Distance (d)

• metres (m) or kilometres (km)– Time (t)

• second (s)• hour (h)

•metres per second (m/s or ms-1)•kilometres per hour (km/h or kmh-1)

Unit of Average Speed (v)

Average Speed

• Measurements – Distance travelled can be measured using a metre

stick or trundle wheel or tape,…. – Time is measured using a stop watch.

distance cover to taken timetravelled distance totalspeed average

tdv

Metres per second or m/s or ms-1

Metres or m

Seconds or s

Remember : • 1 km = 1000 metres• 1 hr = 60 x 60 = 3600s

In physics the units normally used for average speed are:

• m/s (or ms-1)• km/h (or kmh-1)

•Calculations

COPY03/05/23

Example 1A car travels from London to Glasgow (550 miles) in 7 hours.a) What is the average speed of the car in m.p.h.?

tdv

d = 550 miles

t = 7 hours

7550v

mph6.78v

v = ?

b) For a stretch of this journey the car is travelling at 100 km/h. What is this in m/s?

d = 100km

t = 1 hour

= 100 000m

= 60 x 60 = 3600s

v = ?

tdv

3600000 100v

18.27v ms

Open up your notes at page 1, note 1, Average speed, and collect a highlighter or coloured pen.

time

metrestopwatch

dv t

ms

ms -1

v = ? d = 100+50+50+80 = 280 m t = 100 s

v = d t = 280 100 = 2.8 ms -1

Nat 5 Problems Page 2, Questions 1 - 20

Int 2 Problems, Page 32, Questions 1 - 8