Define distance-time graph .

A graph that shows how the distance of an object moving in a straight line (from a starting position) changes over time .

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

The object is stationary (not moving) — its distance from the starting point is not changing over time.

How does the steepness of a straight line on a distance-time graph indicate an object's speed?

A steep slope shows a large speed, and a shallow slope shows a small speed.

What is the difference between a curve with an increasing slope and a curve with a decreasing slope on a distance-time graph?

An increasing slope shows the object's speed is increasing (it is accelerating). A decreasing slope shows the object's speed is decreasing (it is decelerating).

On a distance-time graph, the speed of a moving object can be calculated by finding the ______ of the line.

On a distance-time graph, the speed of a moving object can be calculated by finding the gradient of the line.

True or False? A curved line on a distance-time graph represents an object moving at a constant speed.

False. A curved line shows a changing speed — only a straight line represents a constant speed.

How is the total distance travelled during a journey found from a distance-time graph?

It is given by the final distance value reached — the point where the line ends on the distance axis.

The distance an object travels every second (unit of time).

Define average speed .

A single value representing an object's speed over a whole journey, used because an object's actual speed often varies during travel.

Speed is a ______ quantity because it has a magnitude but no direction.

Speed is a scalar quantity because it has a magnitude but no direction.

True or False? Average speed only takes into account the fastest part of a journey.

False. Average speed is calculated from the total distance moved and the total time taken for the whole journey, not just the fastest part.

How do you use a formula triangle to find an equation for a required quantity?

Cover up the quantity you want to calculate. If the remaining two quantities are on the same line , multiply them; if one is above the other, divide the top by the bottom.

What is the aim of the core practical "investigating motion"?

To investigate the motion of everyday objects (e.g. a paper cone or tennis ball ) by measuring their speed — calculated indirectly from the distance moved and time taken, since speed is difficult to measure directly.

In this experiment, what are the independent and dependent variables?

Independent variable: distance , d . Dependent variable: time , t . Control variable: the same object is used for every measurement.

What is the resolution of the stop clock and of the ruler/tape measure used in this experiment?

Stop clock: 0.01 s . Ruler/tape measure: 1 mm .

How can the systematic error caused by human reaction time be reduced in this experiment?

Use larger distances , producing longer time intervals over which the reaction-time error is less significant, or replace manual timing with light gates and an electronic data logger , which removes reaction-time error entirely.

How can parallax error be avoided when measuring distance with a tape measure or metre rule?

Take all distance readings at eye level , viewing the scale directly rather than at an angle.

The average human reaction time is approximately ______ s, which can introduce a significant timing error when small time intervals are measured.

The average human reaction time is approximately 0.25 s, which can introduce a significant timing error when small time intervals are measured.

True or False? Draughts or air currents have no effect on the accuracy of this experiment.

False. Draughts can affect the motion of the falling object, introducing a random error ; the experiment should be carried out in a still, draught-free space.

What safety precaution should be taken when dropping objects in this experiment?

Place a soft mat or material below the falling object to cushion its fall.

Define acceleration .

The rate of change of velocity — it describes how much an object's velocity changes every second.

If an object is speeding up, its acceleration is ______ ; if it is slowing down, its acceleration is ______ (also called deceleration).

If an object is speeding up, its acceleration is positive ; if it is slowing down, its acceleration is negative (also called deceleration).

True or False? If an object's acceleration is negative, the object is speeding up.

False. A negative acceleration means the object is slowing down (decelerating).

What do the units of acceleration, m/s 2 , actually mean?

They mean the velocity (in m/s) changes by that amount every second — i.e. m/s per second .

Define velocity-time graph .

A graph that shows how the velocity of a moving object varies with time .

What does a straight line on a velocity-time graph represent, and what does the steepness of its slope indicate?

A straight line represents constant acceleration (or deceleration). A steep slope shows a large acceleration; a gentle slope shows a small acceleration.

What does a flat, horizontal line on a velocity-time graph indicate?

The acceleration is zero — the object is moving at a constant velocity .

A ______ gradient on a velocity-time graph shows that an object's velocity is decreasing (it is decelerating).

A negative gradient on a velocity-time graph shows that an object's velocity is decreasing (it is decelerating).

True or False? A positive gradient on a velocity-time graph shows that an object is decelerating.

False. A positive gradient shows increasing velocity — the object is accelerating .

What does the area under a velocity-time graph represent?

The displacement (or distance travelled ) by the object.

How do you find the total distance travelled over a whole journey from a velocity-time graph made up of several enclosed sections?

Add together (sum) the areas of all the enclosed triangles and rectangles under the line.

If an object moves with ______ acceleration, its velocity-time graph consists of straight lines, so the distance travelled can be found from the areas of the enclosed shapes.

If an object moves with constant acceleration, its velocity-time graph consists of straight lines, so the distance travelled can be found from the areas of the enclosed shapes.

True or False? The area under a velocity-time graph represents the object's acceleration.

False. The area represents the object's displacement (or distance travelled), not its acceleration.

Define uniform acceleration .

Constant acceleration — acceleration that does not change.

Why is the equation v 2 = u 2 + 2as particularly useful compared with other equations of motion?

It can be used to find the initial speed, final speed, acceleration, or distance moved without needing to know the time taken .

For an object undergoing uniform acceleration, v 2 = u 2 + ______ .

For an object undergoing uniform acceleration, v 2 = u 2 + 2as .

IGCSEPhysicsEdexcelPhysics (Modular)Unit 1Flashcards1. Forces & MotionMovement & Position

Movement & Position (Edexcel IGCSE Physics (Modular): Unit 1): Flashcards

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Cards in this collection (49)

Define distance-time graph.
A graph that shows how the distance of an object moving in a straight line (from a starting position) changes over time.
What does a flat, horizontal line on a distance-time graph represent?
The object is stationary (not moving) — its distance from the starting point is not changing over time.
How does the steepness of a straight line on a distance-time graph indicate an object's speed?
A steep slope shows a large speed, and a shallow slope shows a small speed.
What is the difference between a curve with an increasing slope and a curve with a decreasing slope on a distance-time graph?
An increasing slope shows the object's speed is increasing (it is accelerating). A decreasing slope shows the object's speed is decreasing (it is decelerating).
On a distance-time graph, the speed of a moving object can be calculated by finding the ______ of the line.
On a distance-time graph, the speed of a moving object can be calculated by finding the gradient of the line.
True or False?
A curved line on a distance-time graph represents an object moving at a constant speed.
False.
A curved line shows a changing speed — only a straight line represents a constant speed.
How is the total distance travelled during a journey found from a distance-time graph?
It is given by the final distance value reached — the point where the line ends on the distance axis.
Define speed.
The distance an object travels every second (unit of time).
Define average speed.
A single value representing an object's speed over a whole journey, used because an object's actual speed often varies during travel.
State the equation for average speed, and give the unit of each symbol.
$average speed = \frac{distance moved}{time taken}$
Average speed in m/s, distance moved in m, time taken in s.
Speed is a ______ quantity because it has a magnitude but no direction.
Speed is a scalar quantity because it has a magnitude but no direction.
True or False?
Average speed only takes into account the fastest part of a journey.
False.
Average speed is calculated from the total distance moved and the total time taken for the whole journey, not just the fastest part.
A plane flies at an average speed of 250 m/s for 2 hours. Calculate the distance it travels.
Convert time to seconds:
$2 hours = 2 \times 60 \times 60 = 7200 s$
Then:
$distance moved = average speed \times time taken = 250 \times 7200 = 1 800 000 m$
How do you use a formula triangle to find an equation for a required quantity?
Cover up the quantity you want to calculate. If the remaining two quantities are on the same line, multiply them; if one is above the other, divide the top by the bottom.
What is the aim of the core practical "investigating motion"?
To investigate the motion of everyday objects (e.g. a paper cone or tennis ball) by measuring their speed — calculated indirectly from the distance moved and time taken, since speed is difficult to measure directly.
In this experiment, what are the independent and dependent variables?
Independent variable: distance, d. Dependent variable: time, t. Control variable: the same object is used for every measurement.
What is the resolution of the stop clock and of the ruler/tape measure used in this experiment?
Stop clock: 0.01 s. Ruler/tape measure: 1 mm.
How can the systematic error caused by human reaction time be reduced in this experiment?
Use larger distances, producing longer time intervals over which the reaction-time error is less significant, or replace manual timing with light gates and an electronic data logger, which removes reaction-time error entirely.
How can parallax error be avoided when measuring distance with a tape measure or metre rule?
Take all distance readings at eye level, viewing the scale directly rather than at an angle.
The average human reaction time is approximately ______ s, which can introduce a significant timing error when small time intervals are measured.
The average human reaction time is approximately 0.25 s, which can introduce a significant timing error when small time intervals are measured.
True or False?
Draughts or air currents have no effect on the accuracy of this experiment.
False.
Draughts can affect the motion of the falling object, introducing a random error; the experiment should be carried out in a still, draught-free space.
What safety precaution should be taken when dropping objects in this experiment?
Place a soft mat or material below the falling object to cushion its fall.
Define acceleration.
The rate of change of velocity — it describes how much an object's velocity changes every second.
State the equation for acceleration, and give the unit of each symbol.
$a = \frac{∆ v}{t}$
a = acceleration in m/s², ∆v = change in velocity in m/s, t = time taken in s.
How is the change in velocity, ∆v, calculated?
$∆ v = v - u$
where v is the final velocity and u is the initial velocity, both in m/s.
If an object is speeding up, its acceleration is ______; if it is slowing down, its acceleration is ______ (also called deceleration).
If an object is speeding up, its acceleration is positive; if it is slowing down, its acceleration is negative (also called deceleration).
True or False?
If an object's acceleration is negative, the object is speeding up.
False.
A negative acceleration means the object is slowing down (decelerating).
A train's velocity decreases from 50 m/s to 42 m/s in 30 s. Calculate its deceleration.
$∆ v = v - u = 42 - 50 = - 8 m/s$
$a = \frac{∆ v}{t} = \frac{- 8}{30} = - 0.27 {m/s}^{2}$
The negative value shows the train is slowing down.
What do the units of acceleration, m/s², actually mean?
They mean the velocity (in m/s) changes by that amount every second — i.e. m/s per second.
Define velocity-time graph.
A graph that shows how the velocity of a moving object varies with time.
What does a straight line on a velocity-time graph represent, and what does the steepness of its slope indicate?
A straight line represents constant acceleration (or deceleration). A steep slope shows a large acceleration; a gentle slope shows a small acceleration.
What does a flat, horizontal line on a velocity-time graph indicate?
The acceleration is zero — the object is moving at a constant velocity.
A ______ gradient on a velocity-time graph shows that an object's velocity is decreasing (it is decelerating).
A negative gradient on a velocity-time graph shows that an object's velocity is decreasing (it is decelerating).
True or False?
A positive gradient on a velocity-time graph shows that an object is decelerating.
False.
A positive gradient shows increasing velocity — the object is accelerating.
State the equation used to find acceleration from a velocity-time graph, and define the terms.
$a = gradient = \frac{∆ y}{∆ x}$
∆y is the change in y (velocity) values; ∆x is the change in x (time) values.
A cyclist's velocity-time graph shows their velocity increasing from 5 m/s to 10 m/s between 5 s and 10 s. Calculate their acceleration in this section.
$a = \frac{∆ y}{∆ x} = \frac{5}{5} = 1 {m/s}^{2}$
What does the area under a velocity-time graph represent?
The displacement (or distance travelled) by the object.
How do you calculate the area under a velocity-time graph when it forms a triangle (the object is accelerating or decelerating)?
$Area = \frac{1}{2} \times base \times height$
How do you calculate the area under a velocity-time graph when it forms a rectangle (the object is moving at a constant velocity)?
$Area = base \times height$
How do you find the total distance travelled over a whole journey from a velocity-time graph made up of several enclosed sections?
Add together (sum) the areas of all the enclosed triangles and rectangles under the line.
If an object moves with ______ acceleration, its velocity-time graph consists of straight lines, so the distance travelled can be found from the areas of the enclosed shapes.
If an object moves with constant acceleration, its velocity-time graph consists of straight lines, so the distance travelled can be found from the areas of the enclosed shapes.
True or False?
The area under a velocity-time graph represents the object's acceleration.
False.
The area represents the object's displacement (or distance travelled), not its acceleration.
A velocity-time graph has three enclosed sections: a triangle of base 40 s and height 17.5 m/s, a rectangle of base 30 s and height 17.5 m/s, and a triangle of base 20 s and height 7.5 m/s. Calculate the total distance travelled.
$A_{1} = \frac{1}{2} \times 40 \times 17.5 = 350 m$
$A_{2} = 30 \times 17.5 = 525 m$
$A_{3} = \frac{1}{2} \times 20 \times 7.5 = 75 m$
Total distance $= 350 + 525 + 75 = 950 m$
Define uniform acceleration.
Constant acceleration — acceleration that does not change.
State the equation for uniform acceleration, and give the unit of each symbol.
$v^{2} = u^{2} + 2 a s$
v = final speed (m/s), u = initial speed (m/s), a = acceleration (m/s²), s = distance moved (m).
Why is the equation v² = u² + 2as particularly useful compared with other equations of motion?
It can be used to find the initial speed, final speed, acceleration, or distance moved without needing to know the time taken.
For an object undergoing uniform acceleration, v² = u² + ______.
For an object undergoing uniform acceleration, v² = u² + 2as.
A car accelerates uniformly from rest at 2.5 m/s² up to a speed of 16 m/s. Calculate the distance it travels while accelerating.
$s = \frac{v^{2} - u^{2}}{2 a} = \frac{16^{2} - 0^{2}}{2 \times 2.5} = \frac{256}{5} = 51.2 m \approx 51 m$
True or False?
For an object that starts from rest, u = 0 in the equation v² = u² + 2as.
True.
Starting from rest means the initial speed u is zero, so the equation simplifies to $v^{2} = 2 a s$ .

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