Forces & Motion Flashcards
How do you know which part of a journey shown on a distance/time graph has the highest speed?
steepest line
What is average speed?
total distance / whole time of journey
Name a scalar and vector measured in metres.
distance, displacement
What is the SI unit for speed?
Meters per second (m/s)
What does acceleration mean?
change in velocity in time
What is the equation for calculating speed?
speed = distance / time
How do we represent forces on diagrams?
arrows, with length depending on size of force
In the acceleration equation, what does the ‘u’ stand for?
Initial velocity
What does a horizontal line on a distance/time graph show?
stationary object
What is the equation for calculating distance?
distance = speed x time
Name a scalar and vector measured in m/s.
Speed, Velocity
What are the units for acceleration?
metres per second squared
How do you work out the gradient of a line on a graph?
vertical difference / horizontal difference
What is the unit for speed if the time is measured in hours and the distance is measured in miles?
miles per hour
How is a stationary object shown on a distance/time graph?
Horizontal line
How fast is your walking speed?
typical pace = 3mph / 5 km/h / 1.4m/s
In the acceleration equation, what does the ‘v’ stand for?
Final Velocity
What is the speed of the sound of air?
approximately 330 m/s
Is mass a vector or scalar?
Scalar
Is energy a vector or scalar?
Scalar
What is the maximum horizontal acceleration students are likely to experience in everyday in life?
about 1.5 m/s ² average family car
What is force?
Push or pull
What is the unit for mass?
Kilograms (Kg)
Why is acceleration a vector?
it is measuring a change in another vector
How can speed be calculated?
From a distance and time
How can you calculate velocity from a distance/time graph?
gradient of line
What is the acceleration due to gravity?
10m/s ² to 1 S.F. / 9.8m/s ² to 2 S.F.
Runner A finishes a race in less time than Runner B. Who is faster?
Runner A
What does a vector have that scalar does not?
Direction
What does a vector have that a scalar does not?
direction
What is the difference between speed and velocity?
Velocity has a direction / is a vector
What is the equation for calculating acceleration?
change in velocity (v-u) / time
What two measurements are needed to calculate speed?
Distance and Time
How is a comstant speed shown on a distance/time graph?
straight, sloping line
What is the unit for speed used on the roads in the UK?
Miles per hour (mph)
What is the maximum legal speed for vehicles on UK roads?
70 mph / 31m/s
What is the equation for calculating acceleration from velocity and time?
Acceleration = change in velocity (v-u) / time
How does the mass of a moving object affect its acceleration?
higher mass, lower concentration
Two forces on an object are in opposite directions. How do we calculate the resultant force?
Find the difference between them
What is the name for the force of the object that acts in the same way as all the other forces combined?
resultant
For the same force, how does reducing the mass of an object affect its acceleration?
increases it
How can friction act to make a car slow down?
in brakes