CALCULATING SPEED AND VELOCITY
1. Determine the average speed of each of the following:
a) A racehorse that wins the 3200m Melbourne Cup race in a time of 200s.
(Answer in ms-1.)
b) A mouse running away from a cat which reaches its hole, 5.0m away, in 3s.
(Answer in ms-1.)
c) A miniature railway train which takes 3 minutes to travel its 150m track. (Answer
in ms-1.)
d) The current marathon record holder who completed the 42km route in 2 hours
and 2 minutes. (Answer in kmh-1.)
2. Convert these units:
a) 5km to m
b) 3 hours to s
c) 2500s to hours
d) 270m to km
e) 60kmh-1 to ms-1
f) 25 ms-1 to kmh-1
3. Find the displacement of each of these:
a) A person cycling north for an hour with an average velocity of 10ms-1.
b) A dolphin swimming west for 5 minutes with an average velocity of 60kmh -1.
c) A snail crawling south with an average velocity of 5cms-1 for 5 seconds.
4. Find the time each of these journeys would take:
a) The drive from Mandurah to Perth, a distance of 71km, at an average speed of
75kmh-1.
b) The walk from Fremantle train station to John Curtin College of the Arts, a
distance of 1.8km, at an average speed of 5kmh-1.
c) The swim from Cottesloe to Rottnest, a displacement of 19.7 km West, at an
average velocity of 1.2ms-1 E.
5. The police set up a speed detector in a 40kmh-1 school zone by placing two cables
across the road, 5m apart. The time taken for cars to cross both cables was
recorded. One car took 0.3 seconds to cross the cables. Was it speeding? If so, by
how much?
6. An aeroplane travels at 800kmh-1. How long does it take to fly between two towns
situated 1000km part?
7. At 1pm a car is situated 45 km south of a town. At 2pm, it is situated 15 km north of
the same town. It travelled in a straight line with constant velocity.
a) What distance did it travel?
b) What is the car’s displacement?
c) What was the car’s average velocity?
8. A toy car travelled down a slope, increasing in velocity at a constant rate. It started
from rest and was travelling with a velocity of 5ms-1 when it reached the bottom of
the slope. Find the average velocity of the car.
ANSWERS
1a) 16ms-1
b) 1.7ms-1
c) 0.83ms-1
d) 20.7kmh-1
2a) 5000m
b) 10 800 s
c) 0.69h
d) 0.27km
e)16.7ms-1
f) 90 kmh-1
3a) 36km
b) 5km
c) 25cm
4a) 0.95h
b) 0.36 h
c) 4.56h
5. It is travelling at 60kmh-1 so it is speeding. It’s 20kmh-1 too fast.
6.1.25h
7a) 60km
b) 60km
c) 60kmh-1
8. 2.5ms-1