6.5.4.1 Describing Motion along a line Flashcards
What does a scalar quantity mean?
A quantity which has magnitude (size) only
What does a vector quantity mean?
A quantity which has magnitude (size) and direction
Is distance a scalar or vector quantity?
Scalar (it has magnitude only)
Is displacement a scalar or vector quantity?
Vector (it has size and direction)
What are the similarities and differences between distance and displacement?
Both measured in metres (m)
Distance - scalar, displacement - vector
A object travels three metres. Is this a measurement of distance or displacement?
Distance - it has magnitude (size) only.
A object travels three metres north. Is this a measurement of distance or displacement?
Displacement - it has a magnitude and direction.
Is speed a scalar or vector quantity?
Scalar (it has magnitude only)
What factors can affect the walking/cycling speed of a person?
Age
Terrain
Fitness
Distance already traveled (tiredness)
What is the difference between average speed and instantaneous speed?
Average speed is a measure of the speed of an object over the whole journey; instantaneous speed is the speed at that particular point in the journey.
What are the typical speeds for walking, running and cycling?
walking ~ 1.5 m/s
running ~ 3.0 m/s
cycling ~ 6.0 m/s
What is the typical value for the speed of sound?
~ 330 m/s
What is the equation for speed?
Speed (m/s) = distance traveled (m) / time taken (s)
What equipment would be required to measure the speed of a person running?
Distance - Tape measure or trundle wheel
Time - stopwatch or timer
Is velocity a scalar or vector quantity?
Vector (it has size and direction)
What are the similarities and differences between speed and velocity?
Both measured in m/s, both are a rate of change (something divided by time)
Speed - scalar, velocity - vector
speed = distance/time, velocity = displacement/time
(HT only) How do speed and velocity vary for an object moving in a circle?
speed is constant
velocity varies from positive to negative and back to positive. Total displacement in one loop is zero (its back where it started) so velocity is zero.
On which axis do distance and time go on a distance-time graph?
Time - x-axis
Distance - y-axis
What type of motion does a flat line represent on a distance time graph?
A object which is stationary/at rest/still
What type of motion does a straight sloped line represent on a distance-time graph?
An object traveling at a constant speed
How can you determine the speed of an object from a distance-time graph?
Its the gradient (rise/run)
How would accelerating motion be represented on a distance-time graph?
A curved line
How can you tell if the speed of an object is faster or slower than another?
The gradient of the line representing the faster motion is higher/steeper than the slower motion (lower/shallower gradient)
(HT only) How can the instantaneous speed of an object be found on a curved (accelerating) distance time graph?
Draw a tangent to the line at the time required. Determine the gradient of the tangent.
What is the equation for acceleration?
acceleration (m/s2) = change in velocity/time taken
What is the unit of acceleration?
m/s2
Determine whether the following quantities are vectors and scalars? Distance, displacement, speed, velocity, acceleration.
Scalar - distance, speed
Vector - displacement. velocity, acceleration
On which axis do velocity and time go on a velocity-time graph?
Time - x-axis
Velocity - y-axis
How could you represent an object at rest on a velocity-time graph?
A flat line along the x-axis (y = 0)
How could you represent an object traveling at a constant velocity on a velocity-time graph?
A flat line. (Along the x-axis is a constant velocity of 0 m/s, but not a safe answer)
What type of motion does a straight sloped line represent on a velocity-time graph?
An object which is accelerating
How can the acceleration be determined from a velocity-time graph?
The gradient (rise/run)
(HT only) What does the area under a velocity-time graph represent?
The displacement
(HT only) How is the displacement of an accelerating object determined?
The area of the triangle (1/2 x base x height).
What do the terms ‘v’, ‘u’, ‘a’ and ‘s’ mean?
v - final velocity
u - initial velocity
a - acceleration
s - displacement
What is the acceleration due to gravity near the surface of the Earth?
9.8 m/s2
Describe what happens when an object is dropped near the surface of the Earth.
Initially accelerates at 9.8 m/s2
Air resistance increases as speed increases
Until air resistance equals the weight
There is no resultant force and the object travels at terminal velocity
What is the name of the maximum velocity traveled by an object falling due to gravity?
Terminal velocity.
Describe an investigation to determine the speed of water ripples in the laboratory.
Set up an oscillator to create ripples; set up a strobe light that creates a still pattern in the waves; determine the frequency from the signal generator/strobe light; using f = 1/T; measure the wavelength with a ruler; use wave speed = frequency x wavelength.
