Describing Motion

Question 1

True or false? Scalar quantities only have a magnitude.

Answer 1

True

Question 2

What is a typical person’s running speed?

Answer 2

3 m/s

Question 3

State which of the following are scalar quantities: distance, velocity, speed, displacement

Answer 3

Distance and speed

Question 4

Name two vector quantities

Answer 4

E.g. Force, acceleration, momentum, weight

Question 5

An ant ambled 0.4 m along Anthony’s arm in 100 seconds. Calculate its average speed.

Answer 5

0.004 m/s

average speed = distance / time = 0.4 / 100 = 0.004 m/s

Question 6

A bird flies 4 km north and then 4 km south. What is the distance travelled? What is the bird’s displacement?

Answer 6

The distance travelled = 4 / 4 = 8 km

The bird finishes as its start point, so its displacement is 0 km

Question 7

Estimate how far sound travels in air in 3 seconds.

Answer 7

1020 m
Speed of sound in air = 340 m/s
distance = speed x time = 340 x 3 = 1020 m

Question 8

Niamh did a wheelie on her bike for the 420 m from her house to the library at an average speed of 6 m/s. How long did it take her?

Answer 8

70s

time = distance / speed = 420 / 6 = 70s