Forces and Motion Flashcards
Units for acceleration due to gravity
m/s2 or N/kg
What is a vector quantity
A quantity with a magnitude and direction eg. velocity
What is a scalar quantity
A quantity that has a magnitude but no direction eg. mass
What is acceleration measured in?
m/s2
What is Newton’s first law?
An object will stay at rest or continue to move at a constant speed in the same direction unless acted upon by a resultant force
How do you find the resultant force of two objects?
Find the difference between both forces
What factors affect the thinking distance of a person in a car?
Alchohol
Poor visibility
Old age
Tiredness
Drugs
What factors can affect the stopping distance of a car?
- Its mass
- Its speed
- The driver’s reaction time
- The condition of the brakes
- The road conditions
- Amount of friction between the tyres and road
What is speed?
How fast an object is moving
What is velocity?
Speed in a certain direction
What is distance?
How far something has or will travel
What is displacement?
Distance in one direction as the fastest route
Give some examples of vector quantities
- All forces (eg. Weight)
- Velocity
- Displacement values
Give some examples of scalar quantities
- Energy
- Speed
- Mass
How are vector quantities shown on diagrams?
With arrows
What does a flat line mean on a distance time graph?
The object is stationary
What does a curve represent on a distance time graph?
Acceleration or deceleration
What does a straight line mean on a distance time graph?
Object is stationary
What does a flat line mean on a velocity time graph?
The object is travelling at a constant speed
What does a diagonal line mean on a velocity time graph?
Acceleration or deceleration
How do you find the distance travelled in a velocity time graph?
You work out the area under the graph
How do you work out the acceleration on a velocity time graph?
Use the equation
Describe an object’s motion if the resultant force is 0
Either:
- It will be travelling at a constant speed
- It will be stationary
What different resistive forces could be acting on a car when in motion?
- Air resistance
- Friction
- Contact force
What is terminal velocity?
The maximum velocity of an object, reached when the forces moving the object are balanced by its frictional forces