Distance is a measure of how far an object travels; it is a scalar quantity with magnitude only.

Define displacement .

Displacement is a measure of how far an object is from its starting position, including direction; it is a vector quantity.

Velocity is the rate of change of displacement .

Define acceleration .

Acceleration is the rate of change of velocity .

Acceleration is the rate of change of .......... .

Acceleration is the rate of change of velocity .

True or False? Average velocity is the same as average speed in a given direction.

False. Speed uses distance while velocity uses displacement , so their magnitudes can differ even for the same motion.

What does the slope of a distance-time graph represent?

Speed . The slope is always zero or positive, since distance is a scalar quantity.

What does a negative slope on a displacement-time graph represent?

Motion in the negative direction .

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

The displacement of the object.

On an acceleration-time graph, the slope is .......... .

On an acceleration-time graph, the slope is meaningless .

True or False? The area under a distance-time graph represents the total displacement.

False. The area under a distance-time graph is meaningless ; only speed-time and velocity-time graphs give distance or displacement from their area.

The area under a velocity-time graph is equal to the .......... of a moving object.

The area under a velocity-time graph is equal to the displacement of a moving object.

How is the area under a velocity-time graph calculated when its shape is not a simple triangle or rectangle?

The area is sectioned into triangles and rectangles , and these smaller areas are calculated and summed.

True or False? The area under a velocity-time graph gives the acceleration of an object.

False. The area under a velocity-time graph gives the displacement ; acceleration is found from the gradient instead.

What do a positive and a negative gradient on a displacement-time graph each represent?

Positive gradient: constant velocity in the positive direction Negative gradient: constant velocity in the negative direction

The steeper the slope of a displacement-time graph, the .......... the velocity.

The steeper the slope of a displacement-time graph, the greater the velocity.

True or False? If the gradient of a displacement-time graph changes from positive to negative, the object has stopped moving.

False. A change in gradient sign means the object's velocity has become negative , i.e. it has changed direction , not stopped.

What two features of an object's motion does a displacement-time graph show?

Its changing position and the direction it is moving, relative to its starting position.

What does a curve with a decreasing gradient on a displacement-time graph represent?

A decreasing velocity (deceleration).

What does the gradient of a velocity-time graph represent?

The acceleration of the object; the larger the gradient, the larger the acceleration.

Define deceleration .

The term used to describe an object that is slowing down .

True or False? An object moving at constant speed cannot be accelerating.

False. Velocity is a vector quantity, so a change in direction alone, even at constant speed, means the object is accelerating.

As velocity is a vector quantity, an object is accelerating if its speed changes, or its .......... changes.

As velocity is a vector quantity, an object is accelerating if its speed changes, or its direction changes.

What condition must apply to an object's acceleration for the kinematic equations of motion to be valid?

The object must move with constant (uniform) acceleration .

In the kinematic equations of motion, what physical quantity does each of the symbols s , u , v , a and t represent?

s = displacement u = initial velocity v = final velocity a = acceleration t = time interval

What are the three steps for solving a problem using the kinematic (SUVAT) equations of motion?

List the known and unknown variables, using the context of the question to deduce any that are not explicitly given Choose the equation that contains only those variables Convert to SI units , substitute the values in, and rearrange algebraically to find the answer

What values should be assigned to the initial velocity, u , and final velocity, v , if an object starts from rest or finishes at rest respectively?

Starts from rest → u = 0 Finishes at rest → v = 0

True or False? When solving a kinematics problem, quantities such as distances in km or cm can be substituted directly into the equations without converting them, as long as the final answer is converted at the end.

False. All quantities must be converted into SI units before they are substituted into the equation, not just the final answer.

The second step of solving a kinematics problem is to choose the .......... that contains the variables already listed as known or unknown.

The second step of solving a kinematics problem is to choose the equation that contains the variables already listed as known or unknown.

What is the aim of the acceleration of free fall experiment?

To determine the acceleration due to gravity , g , by measuring the time taken for a ball-bearing to fall a known height and using an equation of motion.

In the acceleration of free fall experiment, what are the independent and dependent variables?

Independent variable = height , h Dependent variable = time , t

Name three variables that must be controlled in the acceleration of free fall experiment.

Same steel ball-bearing Same electromagnet Same distance between the ball-bearing and the top of the glass tube

How are the electromagnet and light gates used together to obtain the height and time data in this experiment?

The electromagnet holds the ball-bearing and releases it when switched off; the light gates and timer measure t by starting the timer as the ball passes the first light gate and stopping it at the second, with the distance between the gates measured as h .

Give two random errors in the acceleration of free fall experiment and how they can be reduced.

Uncertainty in h from the metre ruler's 1 mm resolution, and parallax error when reading h The ball may not fall through the exact centre of each light gate Reduced by repeating the experiment for each value of h and calculating an average time

The tall clamp stand supporting the apparatus must be secured to the bench with a .......... to keep it rigid during the experiment.

The tall clamp stand supporting the apparatus must be secured to the bench with a G clamp to keep it rigid during the experiment.

True or False? Residual magnetism in the electromagnet after the current is switched off causes the measured time, t , to be recorded as shorter than its true value.

False. Residual magnetism delays the release of the ball-bearing, causing t to be recorded as longer than it should be — this is a systematic error .

Why must the horizontal and vertical components of projectile motion be evaluated separately?

Because the horizontal and vertical components are completely independent of one another.

Define the three key quantities used to describe projectile motion: time of flight, maximum height attained and range.

Time of flight : how long the projectile is in the air Maximum height attained : the height at which the projectile is momentarily at rest (vertically) Range : the horizontal distance travelled by the projectile

For an object undergoing horizontal projection, what is its initial vertical component of velocity?

Zero — at the moment of release, the velocity is entirely horizontal.

The three possible scenarios for projectile motion are vertical projection, horizontal projection and projection at an .......... .

The three possible scenarios for projectile motion are vertical projection, horizontal projection and projection at an angle .

True or False? When calculating the maximum height reached by a projectile launched at an angle, the acceleration due to gravity should be substituted as a positive value in the equations of motion.

False. As the projectile rises, it decelerates , so g must be taken as negative in the equations of motion.

A LevelPhysicsCambridge (CIE)Flashcards2. KinematicsEquations of Motion

Equations of Motion (Cambridge (CIE) A Level Physics): Flashcards

Exam code: 9702

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FrontDisplacement, Velocity & Acceleration
Define distance.

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Cards in this collection (58)

Define distance.
Distance is a measure of how far an object travels; it is a scalar quantity with magnitude only.
Define displacement.
Displacement is a measure of how far an object is from its starting position, including direction; it is a vector quantity.
Define velocity.
Velocity is the rate of change of displacement.
Define acceleration.
Acceleration is the rate of change of velocity.
What are the two equations used to calculate average velocity, $v_{a v g}$ ?
$v_{a v g} = \frac{Δ x}{Δ t}$
$v_{a v g} = \frac{(u + v)}{2}$
Acceleration is the rate of change of ...........
Acceleration is the rate of change of velocity.
True or False?
Average velocity is the same as average speed in a given direction.
False.
Speed uses distance while velocity uses displacement, so their magnitudes can differ even for the same motion.
What does the slope of a distance-time graph represent?
Speed. The slope is always zero or positive, since distance is a scalar quantity.
What does a negative slope on a displacement-time graph represent?
Motion in the negative direction.
What does the area under a velocity-time graph represent?
The displacement of the object.
What does the area under a speed-time graph represent?
The distance travelled.
What does the area under an acceleration-time graph represent?
The change in velocity.
On an acceleration-time graph, the slope is ...........
On an acceleration-time graph, the slope is meaningless.
True or False?
The area under a distance-time graph represents the total displacement.
False.
The area under a distance-time graph is meaningless; only speed-time and velocity-time graphs give distance or displacement from their area.
The area under a velocity-time graph is equal to the .......... of a moving object.
The area under a velocity-time graph is equal to the displacement of a moving object.
How is the area under a velocity-time graph calculated when its shape is not a simple triangle or rectangle?
The area is sectioned into triangles and rectangles, and these smaller areas are calculated and summed.
State the formula for the area of a triangle used when calculating displacement from a velocity-time graph.
$A_{t r i a n g l e} = \frac{1}{2} b h$
State the formula for the area of a rectangle used when calculating displacement from a velocity-time graph.
$A_{r e c t a n g l e} = b h$
True or False?
The area under a velocity-time graph gives the acceleration of an object.
False.
The area under a velocity-time graph gives the displacement; acceleration is found from the gradient instead.
What does the gradient of a displacement-time graph represent?
The velocity of the object.
What do a positive and a negative gradient on a displacement-time graph each represent?
- Positive gradient: constant velocity in the positive direction
- Negative gradient: constant velocity in the negative direction
The steeper the slope of a displacement-time graph, the .......... the velocity.
The steeper the slope of a displacement-time graph, the greater the velocity.
True or False?
If the gradient of a displacement-time graph changes from positive to negative, the object has stopped moving.
False.
A change in gradient sign means the object's velocity has become negative, i.e. it has changed direction, not stopped.
What two features of an object's motion does a displacement-time graph show?
Its changing position and the direction it is moving, relative to its starting position.
What does a curve with a decreasing gradient on a displacement-time graph represent?
A decreasing velocity (deceleration).
What does the gradient of a velocity-time graph represent?
The acceleration of the object; the larger the gradient, the larger the acceleration.
State the equation for acceleration in terms of the change in velocity and time taken.
$a = \frac{Δ v}{Δ t} = \frac{(v - u)}{t}$
where v = final velocity, u = initial velocity
Define deceleration.
The term used to describe an object that is slowing down.
True or False?
An object moving at constant speed cannot be accelerating.
False.
Velocity is a vector quantity, so a change in direction alone, even at constant speed, means the object is accelerating.
As velocity is a vector quantity, an object is accelerating if its speed changes, or its .......... changes.
As velocity is a vector quantity, an object is accelerating if its speed changes, or its direction changes.
What condition must apply to an object's acceleration for the kinematic equations of motion to be valid?
The object must move with constant (uniform) acceleration.
In the kinematic equations of motion, what physical quantity does each of the symbols s, u, v, a and t represent?
- s = displacement
- u = initial velocity
- v = final velocity
- a = acceleration
- t = time interval
State the kinematic equation linking v, u, a and t (no displacement).
$v = u + a t$
State the kinematic equation linking s, u, v and t (no acceleration).
$s = \frac{1}{2} (u + v) t$
State the kinematic equation linking s, u, a and t (no final velocity).
$s = u t + \frac{1}{2} a t^{2}$
The equation $v^{2} = u^{2} + 2 a s$ links final velocity, initial velocity, acceleration and ...........
The equation $v^{2} = u^{2} + 2 a s$ links final velocity, initial velocity, acceleration and displacement.
True or False?
All four kinematic equations of motion are printed on the data sheet provided in the exam, so none need to be memorised.
False.
Only $s = u t + \frac{1}{2} a t^{2}$ and $v^{2} = u^{2} + 2 a s$ are given on the data sheet — $v = u + a t$ and $s = \frac{1}{2} (u + v) t$ must be memorised.
What are the three steps for solving a problem using the kinematic (SUVAT) equations of motion?
- List the known and unknown variables, using the context of the question to deduce any that are not explicitly given
- Choose the equation that contains only those variables
- Convert to SI units, substitute the values in, and rearrange algebraically to find the answer
For an object undergoing vertical motion under gravity, what value and sign should be used for its acceleration, a, in the kinematic equations?
$a = \pm 9.81 {m s}^{- 2}$ , with the sign depending on which direction has been taken as positive.
What values should be assigned to the initial velocity, u, and final velocity, v, if an object starts from rest or finishes at rest respectively?
- Starts from rest → u = 0
- Finishes at rest → v = 0
True or False?
When solving a kinematics problem, quantities such as distances in km or cm can be substituted directly into the equations without converting them, as long as the final answer is converted at the end.
False.
All quantities must be converted into SI units before they are substituted into the equation, not just the final answer.
The second step of solving a kinematics problem is to choose the .......... that contains the variables already listed as known or unknown.
The second step of solving a kinematics problem is to choose the equation that contains the variables already listed as known or unknown.
Which SUVAT equation should be chosen if a problem gives u, v and t, but not the acceleration, a?
$s = \frac{(u + v)}{2} t$ — this is the only kinematic equation that does not contain a.
What is the aim of the acceleration of free fall experiment?
To determine the acceleration due to gravity, g, by measuring the time taken for a ball-bearing to fall a known height and using an equation of motion.
In the acceleration of free fall experiment, what are the independent and dependent variables?
- Independent variable = height, h
- Dependent variable = time, t
Name three variables that must be controlled in the acceleration of free fall experiment.
- Same steel ball-bearing
- Same electromagnet
- Same distance between the ball-bearing and the top of the glass tube
How are the electromagnet and light gates used together to obtain the height and time data in this experiment?
The electromagnet holds the ball-bearing and releases it when switched off; the light gates and timer measure t by starting the timer as the ball passes the first light gate and stopping it at the second, with the distance between the gates measured as h.
In the straight-line analysis of this experiment, what quantities are plotted on the y-axis and x-axis, and what does the gradient represent?
- y-axis = $\frac{2 h}{t}$
- x-axis = t
- Gradient = acceleration due to gravity, g
Give two random errors in the acceleration of free fall experiment and how they can be reduced.
- Uncertainty in h from the metre ruler's 1 mm resolution, and parallax error when reading h
- The ball may not fall through the exact centre of each light gate
- Reduced by repeating the experiment for each value of h and calculating an average time
The tall clamp stand supporting the apparatus must be secured to the bench with a .......... to keep it rigid during the experiment.
The tall clamp stand supporting the apparatus must be secured to the bench with a G clamp to keep it rigid during the experiment.
True or False?
Residual magnetism in the electromagnet after the current is switched off causes the measured time, t, to be recorded as shorter than its true value.
False.
Residual magnetism delays the release of the ball-bearing, causing t to be recorded as longer than it should be — this is a systematic error.
Why must the horizontal and vertical components of projectile motion be evaluated separately?
Because the horizontal and vertical components are completely independent of one another.
Define the three key quantities used to describe projectile motion: time of flight, maximum height attained and range.
- Time of flight: how long the projectile is in the air
- Maximum height attained: the height at which the projectile is momentarily at rest (vertically)
- Range: the horizontal distance travelled by the projectile
After a projectile is released, what is the only force acting on it?
Gravity (its weight).
For an object undergoing horizontal projection, what is its initial vertical component of velocity?
Zero — at the moment of release, the velocity is entirely horizontal.
For a projectile launched at an angle θ to the horizontal with initial velocity u, what are its horizontal and vertical components of initial velocity?
- Horizontal component = $u \cos θ$
- Vertical component = $u \sin θ$
The three possible scenarios for projectile motion are vertical projection, horizontal projection and projection at an ...........
The three possible scenarios for projectile motion are vertical projection, horizontal projection and projection at an angle.
True or False?
When calculating the maximum height reached by a projectile launched at an angle, the acceleration due to gravity should be substituted as a positive value in the equations of motion.
False.
As the projectile rises, it decelerates, so g must be taken as negative in the equations of motion.

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