Define scalar quantity.

A scalar quantity has only a magnitude (size), with no direction, for example mass or distance .

Define vector quantity.

A vector quantity has both magnitude and direction , for example velocity or displacement .

What is the difference between distance and displacement ?

Distance is the total length of the path travelled, with no direction (scalar). Displacement is how far an object is from its starting point, in a straight line, including direction (vector).

In a 300 m race where the finish line is 100 m to the right of the start, what are the athletes' distance travelled and their displacement?

Distance travelled = 300 m. Displacement = 100 m to the right of the start.

Explain why mass is a scalar quantity but weight is a vector quantity.

Mass has magnitude only, so it is a scalar. Weight is a force with both magnitude and direction (due to gravity), so it is a vector.

If athletes run a full 400 m lap and return to their starting point, their total distance is 400 m but their ______ is zero.

If athletes run a full 400 m lap and return to their starting point, their total distance is 400 m but their displacement is zero.

True or False? Speed and velocity are both scalar quantities.

False. Speed is a scalar quantity, but velocity is a vector quantity because it also includes a direction.

Speed is the distance an object travels every second; it is a scalar quantity because it has magnitude only.

A plane flies at an average speed of 250 m/s for 2 hours. Calculate the total distance it travels.

Time = 2 × 60 × 60 = 7200 s. Distance = 250 × 7200 = 1 800 000 m .

When using a formula triangle, covering up the quantity you want to calculate is known as finding the ______ of the equation.

When using a formula triangle, covering up the quantity you want to calculate is known as finding the subject of the equation.

True or False? Speed is a vector quantity.

False. Speed is a scalar quantity because it only has magnitude, with no direction.

Velocity is the speed of an object in a stated direction — a vector quantity, since it has both magnitude and direction.

What two pieces of information must be given to fully describe an object's velocity?

A magnitude (speed) and a direction , for example " 15 m/s south " or " 250 mph on a bearing of 030° ".

Two cars travelling in different lanes at the same speed but in different directions have the same speed but different ______ .

Two cars travelling in different lanes at the same speed but in different directions have the same speed but different velocities .

True or False? Speed is a vector quantity.

False. Speed is a scalar quantity; velocity is the vector quantity, since it also includes a direction.

A car's motion is described only as "15 m/s". Is this a speed or a velocity? Explain your answer.

This describes a speed , since only a magnitude is given. To describe a velocity , a direction would also need to be stated, for example "15 m/s south".

What does a distance-time graph show?

How the distance travelled by an object moving in a straight line changes over time .

What does a flat, horizontal line on a distance-time graph represent?

The object is stationary (not moving).

How can you tell whether an object is moving with a large or small speed from the slope of a straight line on a distance-time graph?

A steep slope represents a large speed; a shallow slope represents a small speed.

What does a curved line on a distance-time graph represent, and how do you tell if the object is speeding up or slowing down?

A curve represents a changing speed . An increasing slope means the object is speeding up ; a decreasing slope means it is slowing down .

The speed of a moving object can be calculated from the ______ of the line on a distance-time graph.

The speed of a moving object can be calculated from the gradient of the line on a distance-time graph.

True or False? A straight, sloped line on a distance-time graph represents an object that is stationary.

False. A straight, sloped line represents constant speed . Only a flat, horizontal line represents a stationary object.

A train travels 8 km in 6 minutes at a constant speed. Calculate its speed in m/s.

Distance = 8000 m, time = 360 s. Speed = 8000 ÷ 360 = 22.2 m/s .

Define acceleration .

Acceleration is the rate of change of velocity — how much an object's velocity changes every second.

True or False? A negative value of acceleration means an object is speeding up.

False. A negative acceleration (deceleration) means the object is slowing down ; a positive acceleration means it is speeding up.

Define the acceleration due to gravity , g .

In the absence of air resistance , all objects near Earth's surface fall with the same acceleration, g = 10 m/s² .

In freefall, with no air resistance, an object's velocity increases by ______ for every second it falls.

In freefall, with no air resistance, an object's velocity increases by 10 m/s for every second it falls.

GCSEScienceEdexcelCombined SciencePhysicsFlashcardsMotion & ForcesDescribing Motion

Describing Motion (Edexcel GCSE Combined Science: Physics): Flashcards

Exam code: 1SC0

1/38

0Still learning

Know0

FrontScalars & Vectors
Define scalar quantity.

Was this flashcard helpful?

Cards in this collection (38)

Define scalar quantity.
A scalar quantity has only a magnitude (size), with no direction, for example mass or distance.
Define vector quantity.
A vector quantity has both magnitude and direction, for example velocity or displacement.
What is the difference between distance and displacement?
Distance is the total length of the path travelled, with no direction (scalar). Displacement is how far an object is from its starting point, in a straight line, including direction (vector).
In a 300 m race where the finish line is 100 m to the right of the start, what are the athletes' distance travelled and their displacement?
Distance travelled = 300 m. Displacement = 100 m to the right of the start.
Explain why mass is a scalar quantity but weight is a vector quantity.
Mass has magnitude only, so it is a scalar. Weight is a force with both magnitude and direction (due to gravity), so it is a vector.
If athletes run a full 400 m lap and return to their starting point, their total distance is 400 m but their ______ is zero.
If athletes run a full 400 m lap and return to their starting point, their total distance is 400 m but their displacement is zero.
True or False?
Speed and velocity are both scalar quantities.
False.
Speed is a scalar quantity, but velocity is a vector quantity because it also includes a direction.
Define speed.
Speed is the distance an object travels every second; it is a scalar quantity because it has magnitude only.
Write the equation used to calculate the speed of an object moving at constant speed.
$s p e e d = \frac{d i s t a n c e t r a v e l l e d}{t i m e t a k e n}$
How is the average speed of an object calculated?
$a v e r a g e s p e e d = \frac{t o t a l d i s t a n c e t r a v e l l e d}{t o t a l t i m e t a k e n}$
A plane flies at an average speed of 250 m/s for 2 hours. Calculate the total distance it travels.
Time = 2 × 60 × 60 = 7200 s. Distance = 250 × 7200 = 1 800 000 m.
When using a formula triangle, covering up the quantity you want to calculate is known as finding the ______ of the equation.
When using a formula triangle, covering up the quantity you want to calculate is known as finding the subject of the equation.
True or False?
Speed is a vector quantity.
False.
Speed is a scalar quantity because it only has magnitude, with no direction.
Define velocity.
Velocity is the speed of an object in a stated direction — a vector quantity, since it has both magnitude and direction.
What two pieces of information must be given to fully describe an object's velocity?
A magnitude (speed) and a direction, for example "15 m/s south" or "250 mph on a bearing of 030°".
Two cars travelling in different lanes at the same speed but in different directions have the same speed but different ______.
Two cars travelling in different lanes at the same speed but in different directions have the same speed but different velocities.
True or False?
Speed is a vector quantity.
False.
Speed is a scalar quantity; velocity is the vector quantity, since it also includes a direction.
A car's motion is described only as "15 m/s". Is this a speed or a velocity? Explain your answer.
This describes a speed, since only a magnitude is given. To describe a velocity, a direction would also need to be stated, for example "15 m/s south".
What does a distance-time graph show?
How the distance travelled by an object moving in a straight line changes over time.
What does a flat, horizontal line on a distance-time graph represent?
The object is stationary (not moving).
How can you tell whether an object is moving with a large or small speed from the slope of a straight line on a distance-time graph?
A steep slope represents a large speed; a shallow slope represents a small speed.
What does a curved line on a distance-time graph represent, and how do you tell if the object is speeding up or slowing down?
A curve represents a changing speed. An increasing slope means the object is speeding up; a decreasing slope means it is slowing down.
The speed of a moving object can be calculated from the ______ of the line on a distance-time graph.
The speed of a moving object can be calculated from the gradient of the line on a distance-time graph.
Write the equation used to calculate speed from the gradient of a distance-time graph.
$s p e e d = g r a d i e n t = \frac{Δ y}{Δ x}$ where Δy is the change in distance and Δx is the change in time.
True or False?
A straight, sloped line on a distance-time graph represents an object that is stationary.
False.
A straight, sloped line represents constant speed. Only a flat, horizontal line represents a stationary object.
A train travels 8 km in 6 minutes at a constant speed. Calculate its speed in m/s.
Distance = 8000 m, time = 360 s. Speed = 8000 ÷ 360 = 22.2 m/s.
Define acceleration.
Acceleration is the rate of change of velocity — how much an object's velocity changes every second.
Write the equation for acceleration, including the unit of each quantity.
$a = \frac{Δ v}{t}$ where a = acceleration (m/s²), Δv = change in velocity (m/s), t = time taken (s).
How is the change in velocity of an object calculated?
$Δ v = v - u$ — final velocity minus initial velocity.
True or False?
A negative value of acceleration means an object is speeding up.
False.
A negative acceleration (deceleration) means the object is slowing down; a positive acceleration means it is speeding up.
Define the acceleration due to gravity, g.
In the absence of air resistance, all objects near Earth's surface fall with the same acceleration, g = 10 m/s².
In freefall, with no air resistance, an object's velocity increases by ______ for every second it falls.
In freefall, with no air resistance, an object's velocity increases by 10 m/s for every second it falls.
Estimate the acceleration of a typical family car that speeds up from 0 m/s to 27 m/s in 10 seconds.
$a = \frac{27 - 0}{10} = 2.7 m / s^{2}$ — about 2.7 m/s².
Write the equation of motion used for uniformly accelerating objects when the time taken is not known.
$v^{2} - u^{2} = 2 a x$ where v = final speed, u = initial speed, a = acceleration, x = distance travelled.
State the units of each quantity in the equation $v^{2} - u^{2} = 2 a x$ .
u and v in metres per second (m/s); a in metres per second squared (m/s²); x in metres (m).
In the equation $v^{2} - u^{2} = 2 a x$ , the letter ______ represents the distance travelled, in metres.
In the equation $v^{2} - u^{2} = 2 a x$ , the letter x represents the distance travelled, in metres.
A car accelerates steadily from rest at 2.5 m/s² up to a speed of 16 m/s. Calculate the distance travelled during this acceleration.
$16^{2} - 0^{2} = 2 \times 2.5 \times x$ , so $256 = 5 x$ , giving x = 51.2 m.
True or False?
The equation $v^{2} - u^{2} = 2 a x$ can only be used if the time taken is known.
False.
This equation is useful precisely because it can be used when the time taken is not known.

Sign up to unlock flashcards

By signing up you agree to our Terms and Privacy Policy

Previous:Expressing Quantities & SI UnitsNext:Forces