What is a scalar quantity? Give two examples.

A quantity with size only, for example distance, speed, time or mass.

What is a vector quantity? Give two examples.

A quantity with size and direction, for example velocity, force, displacement or acceleration.

What is the difference between speed and velocity?

Velocity is speed in a given direction, so it is a vector. Speed is a scalar.

What is the equation for acceleration?

acceleration = change in velocity ÷ time taken (a = Δv ÷ t).

What is the unit of acceleration?

Metres per second squared (m/s²).

What is deceleration?

Negative acceleration: the velocity decreases as the object slows down.

How do you find average speed?

Total distance travelled ÷ total time taken.

What is the acceleration of an object moving at constant velocity?

Zero, because its velocity is not changing.

A car goes round a bend at constant speed. Is its velocity constant?

No. Its direction is changing, so its velocity is changing.

Why is the average velocity of a round trip zero?

The object finishes where it started, so its overall change of position is zero.

Speed, velocity and accelerationIB MYP Sciences: Flashcards

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What is the equation for speed?

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What is the equation for speed?: speed = distance ÷ time (in m/s).
What is a scalar quantity? Give two examples.: A quantity with size only, for example distance, speed, time or mass.
What is a vector quantity? Give two examples.: A quantity with size and direction, for example velocity, force, displacement or acceleration.
What is the difference between speed and velocity?: Velocity is speed in a given direction, so it is a vector. Speed is a scalar.
What is the equation for acceleration?: acceleration = change in velocity ÷ time taken (a = Δv ÷ t).
What is the unit of acceleration?: Metres per second squared (m/s²).
What is deceleration?: Negative acceleration: the velocity decreases as the object slows down.
How do you find average speed?: Total distance travelled ÷ total time taken.
Rearrange v = s ÷ t to find the distance.: s = v × t.
What is the acceleration of an object moving at constant velocity?: Zero, because its velocity is not changing.
A car goes round a bend at constant speed. Is its velocity constant?: No. Its direction is changing, so its velocity is changing.
Why is the average velocity of a round trip zero?: The object finishes where it started, so its overall change of position is zero.

Exam questions on Speed, velocity and acceleration

A cycling club in Nairobi times one of its riders over a straight 1200 m stretch of road. The rider takes 80 s to cover it.
The rider keeps the same average speed. Calculate the distance she travels in 2.0 minutes.2 marks
A sports car on a test track in Dubai starts from rest and accelerates in a straight line, reaching 27 m/s after 6.0 s.
A different car increases its velocity by 20 m/s with an acceleration of 2.5 m/s². Calculate the time this takes.2 marks
Aiko, a student in Osaka, investigates how the height of a ramp affects the speed of a toy car. She releases the car from rest at the top of the ramp and uses a stopwatch to time how long it takes to cross a 1.0 m flat track at the bottom. Each time is the mean of three runs. The mean times are 2.0 s for a ramp height of 5 cm, 1.4 s for 10 cm, 1.1 s for 15 cm and 1.0 s for 20 cm.
State a testable hypothesis for this investigation, giving a scientific reason, and identify the dependent variable.3 marks

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Written by the Exaim team, led by Shaun Daswani (Head of Upper Secondary, Improve ME Institute; MSc Financial Mathematics, Imperial College London; BSc, UCL) and Jason Daswani (operational lead, Improve ME Institute; LSE).