M2.2 Motion equations

Front

What is the average speed equation?

Back

average speed = total distance travelled / time taken

Answer explanation

The correct equation for average speed is 'average speed = total distance travelled / time taken'. This formula shows that speed is calculated by dividing the distance covered by the time it took to cover that distance.

Front

What is the name given to a physical quantity described in both size and direction?

Back

vector

Answer explanation

A physical quantity described in both size and direction is called a vector. The term 'vector' refers specifically to this characteristic, distinguishing it from scalar quantities that only have size.

Front

Which units could NOT be used for the speed of an object? Options: m/s, km/h, s/m, miles per hour

Back

s/m

Answer explanation

The unit 's/m' represents seconds per meter, which is not a valid unit for speed. Speed is defined as distance over time, so valid units include m/s, km/h, and miles per hour.

Front

What physical quantity has the unit metre per second squared?

Back

acceleration, rate of change of speed

Answer explanation

The unit metre per second squared (m/s²) measures acceleration, which is the rate of change of velocity over time. Therefore, the correct answer is acceleration.

Front

Equation for the acceleration of an object?

Back

change in velocity / time taken

Answer explanation

The correct equation for acceleration is the change in velocity divided by the time taken. This reflects how quickly an object's velocity changes over a specific time period.

Front

What is the standard physical unit for displacement?

Back

metre, meter, m

Answer explanation

The standard physical unit for displacement is the metre (or meter in American English), often abbreviated as 'm'. All three options refer to the same unit, but 'metre' is the correct spelling in the International System of Units.

Front

Alternative equation for calculating average speed of an object?

Back

(initial speed + final speed) / 2

Answer explanation

The average speed can be calculated using the formula (initial speed + final speed) / 2. This accounts for the average of the two speeds over the time taken, making it the correct choice.

Front

Symbol equation for acceleration?

Back

a = (v - u) / t

Answer explanation

The correct formula for acceleration (a) is a = (v - u) / t, where v is final velocity, u is initial velocity, and t is time. This equation shows how acceleration is the change in velocity over time.

Front

Re-arrange the equation a = (v-u)/t to make 'change in velocity' the subject.

Back

change in velocity = acceleration x time taken

Answer explanation

To isolate 'change in velocity' in the equation a = (v-u)/t, multiply both sides by t: change in velocity = a x t. Thus, the correct choice is 'change in velocity = acceleration x time taken'.

Front

If a car travels 60km in 30 minutes, what is its velocity in km/h? v = s/t

Back

120 km/h

Answer explanation

To find the velocity, use the formula v = s/t. Here, s = 60 km and t = 0.5 hours (30 minutes). Thus, v = 60 km / 0.5 h = 120 km/h. Therefore, the correct answer is 120 km/h.