𝛥𝑑 𝑑𝑓 − 𝑑𝑖
→=
=
𝑣
𝛥𝑡
𝑡𝑓 − 𝑡𝑖
1. A ball is rolling down a hill at a constant velocity. You notice that it took 30 seconds for the ball
to roll down a 100m hill. Calculate the velocity. 1.33m/s
2. The drive to Toronto is approximately 550km from Montreal. How many hours would it take to
get there if you are driving an average of 100km/h? 5.5 hours
3. You completed the 100m dash in exactly 18.5seconds. Calculate your speed in both m/s and
km/h. 5.41m/s and 19.46 km/h
4. Light travels at approximately 300,000,000 m/s. How long does it take for light the reach Earth,
if the sun is located 149,600,000 km? (Whatever your answer is, it takes that long for light from
the sun to reach us. That means that if something were to happen on the sun, we’d only be
aware after that amount of time). 8.31 minutes
5. At a horse race, you have a camera that takes a picture of the horses every second for 10
seconds. The displacement of the horse is shown in the table below after each picture.
Position relative
to the start [m]
0.
10.
21.
33.
45.
59.
73.
83.
92.
100.
105.
Time elapsed [s]
0
1
2
3
4
5
6
7
8
9
10
a) Calculate the average velocity of this horse’s 100m dash. 11.1m/s
b) Calculate the instantaneous velocity of the horse between seconds 1 and 2. 10.5m/s and
11m/s
c) After how many seconds did the horse begin to slow down? After 6 seconds
d) Roughly plot the horse’s progress on a position vs time graph.
6. You decide to swim across a fast flowing river. Your effort velocity is 9.0m/s perpendicular to
the flow of the river. The river itself exerts a velocity of 11.0m/s.
a) Determine your resulting velocity across the river. 13.82m/s N51°E
b) How long will it take for you to swim across if the river is 20m wide? 2.30s (you need to
use similar triangles to figure out how far you need to need swim in the diagonal and
then divide that distance by the velocity obtained in a)