Topic 2 - Motion and Forces Flashcards
What is velocity?
Speed in a given direction.
What is a scalar?
A quantity with only magnitude.
Give three examples of scalars
Distance, speed, mass, energy…
Give three examples of vectors
Displacement, velocity, acceleration, momentum, force…
What is displacement?
The distance something is from its starting point.
What is a vector?
A quantity with magnitude and direction.
speed (s) =
distance(d)/time(t)
velocity (v) =
displacement(d)/time(t)
distance (d) =
speed(s)*time(t)
Distance-Time Graphs (pg 14)
Make sure you can analyse them
What measurement does the gradient of a distance-time graph show?
Speed
acceleration (a) =
change in velocity(v-u)/time(t)
What measurement does the gradient of a velocity-time graph show?
Acceleration
How do you measure distance travelled with a velocity-time graph?
Use the area under the graph
v^2 - u^2 =
2ax
Light gate practical (pg 18)
Understand it
What is average wind speed (in m/s)?
3-6 m/s
What is the speed of sound (in m/s)?
About 340 m/s
What is average walking speed (in m/s)?
1.5-2.5 m/s
What is average running speed (in m/s)?
5-7 m/s
What is average cycling speed (in m/s)?
5-8 m/s
What is the value of g (to the nearest integer)?
10 m/s^2
What is Newton’s first law?
An object will stay stationary or at a constant speed unless acted upon by unbalanced forces.
In Newton’s second law, what are the two equations that define resultant force?
resultant force (F) = inertial mass(m)*acceleration(a) = change in momentum(mv-mu)/time(t)
weight (W) =
mass(m)*gravitational field strength(g)
Is an object moving in a circular orbit at constant speed changing velocity?
Yes
Centripetal force (pg. 17)
Understand this
What is inertial mass?
How difficult it is to change the velocity of an object.
momentum (p) =
mass(m)*velocity(v)
Momentum (pg 20)
Understand this
What is a way of measuring reaction time?
The ruler drop experiment (pg. 22)
stopping distance =
thinking distance + braking distance
Name 3 factors that affect the stopping distance of a vehicle
mass of vehicle, speed of vehicle, driver’s reaction time, state of brakes, state of tires, friction between tire and road
Name 2 factors that could affect a driver’s reaction time
Age, distractions, tiredness, sobriety
inertial mass (m) =
force(F)/acceleration(a)
Velocity-Time Graphs (pg 15)
Make sure you can analyse them
What are typical stopping distances for vehicles going at 30mph, 50mph and 70mph?
30mph -> 23m
50mph -> 53m
70mph -> 96m
What is the relationship between speed and braking distance?
Speed^2 is directly proportional to braking distance.
