1.1 Describing motion

Pick the qualitative descriptions.

• 3 m s⁻¹

• fast

• N45°W

• one metre

• heavy

Answer explanation

Qualitative descriptions express qualities or characteristics. 'Fast' and 'heavy' describe speed and weight, respectively, while '3 m s⁻¹' and 'one metre' are quantitative measurements, and 'N45°W' is a directional indicator.

Pick the vectors.

• distance

• mass

• acceleration

• time

• velocity

Answer explanation

Acceleration and velocity are vectors because they have both magnitude and direction. Distance, mass, and time are scalar quantities, which only have magnitude.

State if each sentence is describing distance, displacement, speed, velocity or acceleration. Walk 5 m to the left.

• displacement

• distance

• speed

• acceleration

Answer explanation

The sentence describes a change in position (5 m to the left), which is a characteristic of displacement. Displacement refers to the shortest distance from the initial to the final position, including direction.

State if each sentence is describing distance, displacement, speed, velocity or acceleration. The ruler is 1 m long.

• distance

• displacement

• speed

• velocity

• acceleration

Answer explanation

The sentence describes the length of the ruler, which is a measure of distance. Distance refers to the total path covered, regardless of direction, making 'distance' the correct choice.

State if each sentence is describing distance, displacement, speed, velocity or acceleration. If you drop a ball, gravity will make it go faster by 9.8 m s⁻².

• distance

• displacement

• speed

• acceleration

Answer explanation

The sentence describes how the speed of the ball increases due to gravity, specifically stating that it accelerates at 9.8 m s⁻². This indicates a change in velocity over time, which defines acceleration.

State if each sentence is describing distance, displacement, speed, velocity or acceleration. If you drop a ball, one second later it will be moving down at 9.8 m s⁻¹.

• distance

• displacement

• speed

• velocity

• acceleration

Answer explanation

The sentence describes the ball's motion after one second, indicating its speed in a specific direction (downward). This is a definition of velocity, which includes both speed and direction.

State if each sentence is describing distance, displacement, speed, velocity or acceleration. You can travel at 60 km h⁻¹ on the main road.

• speed

• distance

• displacement

• acceleration

Answer explanation

The sentence describes a rate of travel, specifically how fast you are going, which is defined as speed. Speed is the distance traveled per unit of time, in this case, 60 km/h.

State if each sentence is describing distance, displacement, speed, velocity or acceleration. The aeroplane is flying at 880 km h⁻¹ at N45°W.

• distance

• displacement

• speed

• velocity

• acceleration

Answer explanation

The sentence describes the aeroplane's speed (880 km h⁻¹) and direction (N45°W). Since it includes both magnitude and direction, it is classified as velocity, not just speed.

What does the symbol Δd represent in the formula for speed: v = Δd/Δt?

• Change in distance

• Change in time

• Change in speed

• Change in velocity

Answer explanation

In the formula v = Δd/Δt, Δd represents the change in distance traveled over a specific time interval. This is why the correct answer is 'Change in distance', as it directly relates to the calculation of speed.

What does the symbol Δt represent in the formula for speed: v = Δd/Δt?

• Change in distance

• Change in time

• Change in speed

• Change in velocity