Section 1 - Motion and Forces Flashcards
What do vector quantities have?
have a magnitude (size) and a direction
What are some examples of Vector quantities?
force, velocity, displacement, weight, acceleration & deceleration, momentum
What do scalar quantities have?
only have magnitude and no direction
What are some examples of scalar quantities?
speed, distance, mass, energy, temperature, time
What is distance? And is it a scalar or vector quantity?
Displacement is how far an object has moved
scalar quantity–> no direction
What is displacement? And is vector or scalar? explain why?
a measurement of the distance and direction in a straight line from an objects starting point to it’s finishing point
vector quantity–>magnitude & direction
What do speed and velocity both measure?
both measures how fast an object is going
what is the difference between speed and velocity? And which one is scalar and which one is vector?
speed is how fast your going with no regard to the direction (scalar)
Velocity is speed in a given direction (vector)
Give an example of speed and velocity
speed = 30 mph/ 20m/s
velocity = 30 mph north / 20m/s, 060°
What happens when an object has a changing direction but stays at the same speed? (scientifically)
the object is travelling at a constant speed with a changing velocity
How can you relate the speed and time of an object’s distance travelled through a formula?
distance travelled (m) = (average) speed (m/s) x time (s)
What are the typical speeds for walking, running and cycling?
walking = 1.4 m/s (5km/h)
running = 3 m/s (11km/h)
cycling = 5.5 m/s (20km/h)
What are the typical speeds for cars in a built-up area and cars on a motorway?
cars in a built-up area = 13m/s (47km/h)
cars on a motorway = 31 m/s (112km/h)
What are the typical speeds for aeroplanes, trains and ferries?
aeroplanes = 250 m/s (900 km/h)
trains = 55 m/s (200 km/h)
ferries = 15 m/s (54km/h)
What’s the typical wind speed and speed of sound in air?
wind speed = 5-20m/s
speed of sound in air = 340m/s
What equipment would you use for measurements of distances less 1m and times greater than 5s? (common measurement done in schools)
stopwatch and metre rulers
What equipment is best used to measure distance and time in short time intervals? And why?
light gates
gets rid of human error (caused by reaction times)
What is the best equipment used to measure distance and time for measuring a person’s walking speed? And why?
rolling tape measures
optimal for long distances
markers to measure and mark out distances
What’s the more expensive high-tech way that can be used to measure distance and time for measuring a object’s walking speed?
calculating the frames per second of an object to find out the distance it has travelled
How does the more high tech method to calculating a object’s walking speed work? (give 3 steps)
1)record moving object & look at how far it travels each frame
2) find out how many frames per second were recorded
3)find the distance travelled by object in the frames & time taken
what is a physical quantity?
anything that can be measured
How can a vector be shown in a drawn description?
drawn as an arrow
length of arrow = magnitude of force
What is an arrow that is twice as long as the other trying to represent?
represents a force which has twice the magnitude than the other force
what is acceleration?
the change in velocity in a certain amount of time
How do you find the average acceleration of an object?
(explain)
a = (v-u)/ t
a = acceleration (m/s^2)
(v-u) = change in velocity (m/s)
v = final velocity (m/s)
u = initial velocity (m/s)
t = time (s)
what is initial velocity?
starting velocity of an object
What is negative acceleration and what is called (scientifically)?
if an object slows down, the change in velocity is negative (negative acceleration)
deceleration
what are the differences of constant and uniform acceleration?
CA-> moving object moves in a direction doesn’t change direction
UA-> moving object covers an equal distance in an equal duration of time
What is the similarity between a constant acceleration and uniform acceleration?
the acceleration of an object in constant and uniform acceleration is 0 (no change in velocity)
What is uniform acceleration (def.)?
acceleration due to gravity(g) that is uniform for objects in free fall
What’s the equation for calculating uniform acceleration?
v^2-u^2 = 2 x A x X
v^2= final velocity (m/s)
u^2 = initial velocity (m/s)
a= acceleration (m/s^2)
x = distance (m)
What would happen to two objects that are accelerating due to gravity if other forces such as air resistance didn’t act upon it?
They would accelerate at the same rate if gravity was the only force acting
e.g bowling ball & feather
what is the gradient equal to in a distance/time graph?
speed
How do you calculate the speed of an object on a straight line in a distance/time graph?
speed = gradient= change in vertical/ change in horizontal
What is non-uniform motion?
How do you calculate the average speed of an object when it has non-uniform motion?
acceleration or deceleration
total distance travelled/ time taken to travel distance
what is the gradient equal to in a velocity/time graph?
acceleration
What does the gradient, flat sections, steeper graph, curves, steeper curves, levelling off curves represent in a distance/time graph?
gradient (slope) at any point = speed of the object
flat section = stopped
steeper graph = going faster
curves = acceleration
curve getting steeper = speeding up (increasing gradient)
levelling off curve = slowing down (decreasing gradient)
What does the gradient, flat sections, steeper graph, uphill/downhill sections and curves in a velocity/time graph represent?
gradient = acceleration
flat sections = steady speed
steeper the graph= greater the acceleration/deceleration
uphill sections (/) = acceleration
downhill sections ()= deceleration
curve = changing acceleration
What is the gradient equal to in a velocity/time graph? (equation)
gradient = acceleration = change in velocity / time
what is the resultant force?
the resultant force is the overall force on a point/object
