Speed is the distance travelled per unit time .

True or False? Speed is a vector quantity.

False. Speed is a scalar quantity because it only contains magnitude.

Define average speed .

Average speed is the total distance travelled divided by the total time taken.

What does velocity describe that speed does not?

Velocity describes both magnitude and direction of motion whereas speed describes only magnitude.

Velocity is defined as the rate of change of displacement with respect to time.

True or False? Velocity is a scalar quantity.

False. Velocity is a vector quantity because it includes direction .

What units are used to measure speed and velocity?

Both speed and velocity are measured in metres per second (m/s).

What is the significance of negative velocity values?

The significance of negative velocity values indicates motion in the opposite direction.

How is displacement different from distance in calculating velocity?

Displacement is different from distance in calculating velocity because it accounts for direction.

What is the difference between speed and velocity?

The difference between speed and velocity is that speed is a scalar , while velocity is a vector as it includes direction.

How do you calculate the total distance from the average speed?

The total distance is calculated from the average speed by multiplying the average speed by the total time taken.

Define acceleration .

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

An object that speeds up has a ______ acceleration, while an object that slows down has a ______ acceleration, sometimes called deceleration.

An object that speeds up has a positive acceleration, while an object that slows down has a negative acceleration, sometimes called deceleration.

What units are used to measure acceleration ?

Acceleration is measured in metres per second squared (m/s²) .

How is constant speed represented on a distance-time graph?

On a distance time graph, constant speed is represented by a straight line : a steeper slope shows a greater constant speed a shallower slope shows a lower constant speed a flat, horizontal line shows a constant speed of zero

How is changing speed represented on a distance-time graph?

On a distance-time graph, changing speed is represented by a curved line .

What does a speed-time graph show?

A speed-time graph shows how the speed of a moving object varies with time .

What is constant acceleration on a speed-time graph?

Constant acceleration on a speed-time graph is represented by a straight , sloping line .

True or False? A gentle slope on a speed-time graph represents large acceleration.

False. A gentle slope on a speed-time graph represents a small acceleration.

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

A flat, horizontal line indicates that the acceleration is zero , meaning the object is moving at a constant speed.

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

The area under a speed-time graph represents the distance travelled by the object.

How do you calculate the total area under a speed-time graph?

The total area under a speed-time graph shows the total distance travelled. The total area is the sum of the areas of each enclosed section (triangle or rectangle).

What shape does the area beneath a speed-time graph form for an object with constant speed ?

The area under a speed-time graph forms a rectangle .

True or False? A flat line on a speed-time graph indicates constant acceleration.

False. A flat line on a speed-time graph indicates constant speed .

What type of line on a speed-time graph represents constant acceleration ?

A non-horizontal straight line .

How would increasing acceleration appear on a speed-time graph?

As an upward curve with an increasing gradient .

How would decreasing acceleration appear on a speed-time graph?

As an upward curve with a decreasing gradient .

How can you tell whether deceleration is constant, increasing or decreasing from a speed-time graph?

A straight downward line shows constant deceleration. A downward curve with an increasing gradient shows increasing deceleration. A downward curve with a decreasing gradient shows decreasing deceleration.

acceleration = gradient = ______ ÷ ______

acceleration = gradient = rise ÷ run

True or False? On a speed-time graph, deceleration is always shown by a straight line.

False. Deceleration can be shown by a straight line ( constant deceleration) or a curve ( increasing or decreasing deceleration).

Define the acceleration of free fall ( g ).

The acceleration of free fall is the constant acceleration of an object falling with no air resistance, equal to about 9.8 m/s^2^ near the Earth's surface. It is the same for all objects, regardless of mass.

Define terminal velocity .

Terminal velocity is the constant, maximum speed reached by a falling object when the upward force of air resistance has increased enough to balance its weight, giving zero resultant force.

Why do all objects fall with the same acceleration in the absence of air resistance?

The acceleration of free fall, g , does not depend on mass — every object experiences the same gravitational acceleration regardless of how heavy it is.

A skydiver falling through the air experiences two forces: ______ acting downwards and ______ acting upwards.

A skydiver falling through the air experiences two forces: weight acting downwards and air resistance acting upwards.

True or False? When a skydiver opens their parachute, they begin to move upwards.

False. The increased air resistance makes the skydiver decelerate to a new, slower terminal velocity — they do not move upwards.

Describe how a skydiver's acceleration changes from the moment they jump until they reach terminal velocity.

Initially, air resistance is small compared to weight, so the skydiver accelerates . As speed increases, air resistance increases, so the resultant force (and acceleration) decreases . When air resistance equals weight, the resultant force is zero and the skydiver falls at a constant terminal velocity .

O LevelPhysicsCambridge (CIE)Flashcards1. Motion, Forces & Energy1.2 Motion

1.2 Motion (Cambridge (CIE) O Level Physics): Flashcards

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Cards in this collection (52)

What is speed?
Speed is the distance travelled per unit time.
True or False?
Speed is a vector quantity.
False.
Speed is a scalar quantity because it only contains magnitude.
Define average speed.
Average speed is the total distance travelled divided by the total time taken.
State the equation for calculating average speed.
The equation for calculating average speed is $Average speed = \frac{distance travelled}{time taken}$
What does velocity describe that speed does not?
Velocity describes both magnitude and direction of motion whereas speed describes only magnitude.
Define velocity.
Velocity is defined as the rate of change of displacement with respect to time.
What is the equation for calculating velocity?
The equation for velocity is $v = \frac{s}{t}$
Where:
- $v$ = velocity, measured in metres per second (m/s)
- $s$ = displacement, measured in metres (m)
- $t$ = time, measured in seconds (s)
True or False?
Velocity is a scalar quantity.
False.
Velocity is a vector quantity because it includes direction.
What units are used to measure speed and velocity?
Both speed and velocity are measured in metres per second (m/s).
What is the significance of negative velocity values?
The significance of negative velocity values indicates motion in the opposite direction.
How is displacement different from distance in calculating velocity?
Displacement is different from distance in calculating velocity because it accounts for direction.
What is the difference between speed and velocity?
The difference between speed and velocity is that speed is a scalar, while velocity is a vector as it includes direction.
How do you calculate the total distance from the average speed?
The total distance is calculated from the average speed by multiplying the average speed by the total time taken.
Define acceleration.
Acceleration is the rate of change of velocity — how much an object's velocity changes every second.
State the equation for acceleration, defining each symbol and its unit.
$a = \frac{Δ v}{Δ t}$
a = acceleration in metres per second squared (m/s²)
Δv = change in velocity in metres per second (m/s)
Δt = time taken in seconds (s)
How is the change in velocity of an object calculated?
$∆ v = v - u$
Change in velocity = final velocity (v) − initial velocity (u), both measured in metres per second (m/s).
An object that speeds up has a ______ acceleration, while an object that slows down has a ______ acceleration, sometimes called deceleration.
An object that speeds up has a positive acceleration, while an object that slows down has a negative acceleration, sometimes called deceleration.
What units are used to measure acceleration?
Acceleration is measured in metres per second squared (m/s²).
A train decelerates at a constant rate. Its velocity decreases from 50 m/s to 42 m/s in 30 seconds. Calculate its acceleration.
$a = \frac{∆ v}{∆ t} = \frac{42 - 50}{30} = - 0.27 m / s^{2}$
The negative value shows the train is slowing down.
Which type of graph shows the distance travelled by a moving object over a period of time?
A distance-time graph shows the distance travelled by a moving object over a period of time.
How is constant speed represented on a distance-time graph?
On a distance time graph, constant speed is represented by a straight line:
- a steeper slope shows a greater constant speed
- a shallower slope shows a lower constant speed
- a flat, horizontal line shows a constant speed of zero
How is changing speed represented on a distance-time graph?
On a distance-time graph, changing speed is represented by a curved line.
State the equation used to find the gradient of a distance-time graph.
The equation used to find the gradient of a distance-time graph is $speed = gradient = \frac{∆ y}{∆ x}$
Where:
- $∆ y$ = change in distance
- $∆ x$ = change in time
Which line on the distance-time graph shows the slowest speed?
On a distance-time graph, the line with the smallest gradient has the slowest speed. This is the shallowest line (the orange line).
True or False?
This distance-time graph shows a stationary object.
True.
A flat, horizontal line on a distance-time graph shows that the object is stationary. The distance the object has travelled is not changing with time.
Describe the motion of the object shown in this distance-time graph.
The object in this distance-time graph has an increasing speed. The distance it travels in each interval of time is increasing; therefore, the line curves upward.
What does a speed-time graph show?
A speed-time graph shows how the speed of a moving object varies with time.
What is constant acceleration on a speed-time graph?
Constant acceleration on a speed-time graph is represented by a straight, sloping line.
True or False?
A gentle slope on a speed-time graph represents large acceleration.
False.
A gentle slope on a speed-time graph represents a small acceleration.
Describe the motion shown in this speed-time graph.
The speed-time graph shows decreasing acceleration.
The change in speed per unit time decreases.
What does a flat, horizontal line represent on a speed-time graph?
A flat, horizontal line indicates that the acceleration is zero, meaning the object is moving at a constant speed.
What does the area under a speed-time graph represent?
The area under a speed-time graph represents the distance travelled by the object.
How do you calculate the total area under a speed-time graph?
The total area under a speed-time graph shows the total distance travelled. The total area is the sum of the areas of each enclosed section (triangle or rectangle).
What is the formula to calculate the area of a triangle?
The formula to calculate the area of a triangle is $A = \frac{1}{2} \times b \times h$
Where:
- $b$ = base of triangle, measured in metres (m) or centimetres (cm)
- $h$ = height of triangle, measured in metres (m) or centimetres (cm)
What is the formula to calculate the area of a rectangle?
The formula to calculate the area of a rectangle is $A = b \times h$
Where:
- $b$ = base of rectangle, measured in metres (m) or centimetres (cm)
- $h$ = height of rectangle, measured in metres (m) or centimetres (cm)
What shape does the area beneath a speed-time graph form for an object with constant speed?
The area under a speed-time graph forms a rectangle.
True or False?
A flat line on a speed-time graph indicates constant acceleration.
False.
A flat line on a speed-time graph indicates constant speed.
True or False?
The starting speed of this object is zero.
False.
The starting speed is not zero because the line does not start from the origin.
What type of line on a speed-time graph represents constant acceleration?
A non-horizontal straight line.
How would increasing acceleration appear on a speed-time graph?
As an upward curve with an increasing gradient.
How would decreasing acceleration appear on a speed-time graph?
As an upward curve with a decreasing gradient.
How can you tell whether deceleration is constant, increasing or decreasing from a speed-time graph?
A straight downward line shows constant deceleration. A downward curve with an increasing gradient shows increasing deceleration. A downward curve with a decreasing gradient shows decreasing deceleration.
State the equation used to calculate acceleration from a speed-time graph.
$a c c e l e r a t i o n = g r a d i e n t = \frac{r i s e}{r u n}$
acceleration = gradient = ______ ÷ ______
acceleration = gradient = rise ÷ run
True or False?
On a speed-time graph, deceleration is always shown by a straight line.
False.
Deceleration can be shown by a straight line (constant deceleration) or a curve (increasing or decreasing deceleration).
Define the acceleration of free fall (g).
The acceleration of free fall is the constant acceleration of an object falling with no air resistance, equal to about 9.8 m/s^2^ near the Earth's surface. It is the same for all objects, regardless of mass.
Define terminal velocity.
Terminal velocity is the constant, maximum speed reached by a falling object when the upward force of air resistance has increased enough to balance its weight, giving zero resultant force.
State the equation linking weight, mass and gravitational field strength.
$W = m g$
W = weight (N)
m = mass (kg)
g = gravitational field strength
Why do all objects fall with the same acceleration in the absence of air resistance?
The acceleration of free fall, g, does not depend on mass — every object experiences the same gravitational acceleration regardless of how heavy it is.
A skydiver falling through the air experiences two forces: ______ acting downwards and ______ acting upwards.
A skydiver falling through the air experiences two forces: weight acting downwards and air resistance acting upwards.
True or False?
When a skydiver opens their parachute, they begin to move upwards.
False.
The increased air resistance makes the skydiver decelerate to a new, slower terminal velocity — they do not move upwards.
Describe how a skydiver's acceleration changes from the moment they jump until they reach terminal velocity.
Initially, air resistance is small compared to weight, so the skydiver accelerates. As speed increases, air resistance increases, so the resultant force (and acceleration) decreases. When air resistance equals weight, the resultant force is zero and the skydiver falls at a constant terminal velocity.

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