Topic 2- Motion and Forces Flashcards
What is the difference between Scalar and Vector quantities?
- They both have magnitude (number)
- Vector has a direction
Recall 4 scalar quantities
- Speed
- Mass
- Energy
- Distance
Recall 6 vector quantities
- Velocity
- Weight
- Displacement
- Force
- Momentum
- Acceleration
magnitude in a stated directionn
What is the equation for speed?
Distance/ Time
What shows the object is stationary on a distance time graph?
speed time graph
flat line
What shows the object is stationary on a velocity time graph?
Velocity time graph
Flat line at 0
How can we calculate speed from a distance time graph?
The gradient
(draw tangent for curve)
What shows the object is slowing down on a velocity time graph ?
Velocity time graph
- Negative gradient line
- Decelerating
What shows the object is at its fastest on a distance time graph?
Distance time graph
the steepest line
What shows the object is at a constant speed on a distance time graph?
Distance time graph
straight line
How to work out the avg velocity on a velocity time graph?
- Find displacement (area under line)
- Divide by total time taken
What shows the object is returning to the start on a distance time graph?
Negative gradient
What shows the object accelerating/ decelerating on a distance time graph?
Curved line (change in speed)
What shows the object is returning/changed direction on a velocity time graph?
-line in negative y coordinates
How to calculate acceleration with speed and time?
Change in speed/ time
What is acceleration?
How much the speed/velocity changes per second. (rate of speed)
How to calculate acceleration (a) with distance?
change in velocity^2= 2 x distance x a
Describe a range of laboratory methods for determining the speed of objects
Light gates and stopwatch
1) One light gate
2) Measure length of card (shows how fast it moves across)
4) Input on data logger
5) Data logger times how long card intercepts it
Distance (card)/ Time (card intercepted)= speed
----->Use stopwatch and known distance
Avg speed of:
Walking
Runnning
Cycling
Car
Train
Plane
-1.5m/s
-3m/s
-6m/s
-13—>30m/s
-50m/s
-235m/s
Avg speed of
Sound
331.5m/s
What is the acceleration at freefall?
10m/s^2
What is Newton’s first law?
- Object at rest remains at rest
- Object in motion will remain in a constant velocity unless acted upon (as there is nothing to keep it moving faster, or stop it)
and units
What is Newton’s second law?
F=ma
- Acceleration and Force are proportional
—–> (mass is constant)
- F (N)
- M (kg) (inertial mass)
- A (m/s^2)
inertial mass
What is Newton’s third law?
- Every action has an equal but opposite reaction
firing a gun cuases backfrie
pushing a table results in me feeling force