5. Forces Flashcards
What is a scalar?
Quantities that are fully described by magnitude or size
What are vectors?
Quantities that are fully described by both a magnitude and direction
What is distance?
A scalar quantity that refers to ‘how much ground an object has covered’
What is displacement?
A vector quantity that refers to ‘how far out of place an object is’
What is magnitude?
Size
How can vectors be drawn?
Using arrows
Is time a vector or scalar quantity?
scalar
Is force a vector or scalar quantity?
Vector
Is friction a vector or scalar quantity?
Vector
Is weight a vector or scalar quantity?
Vector
Is displacement a vector or scalar quantity?
Vector
Is distance a vector or scalar quantity?
Scalar
Is density a vector or scalar quantity?
Scalar
Is energy a vector or scalar quantity?
Scalar
Is frequency a vector or scalar quantity?
Scalar
Is mass a vector or scalar quantity?
Scalar
Is power a vector or scalar quantity?
Scalar
Is voltage a vector or scalar quantity?
Scalar
Is volume a vector or scalar quantity?
Scalar
What is the gradient on a distance-time graph?
Velocity
What is the gradient on a velocity-time graph?
Acceleration
What is the area under a velocity-time graph?
The distance
What is acceleration?
When an object speeds up or changes direction
What is the total area underneath a velocity-time graph?
The total distance travelled
What is the unit of force?
Newtons, N
Examples of contact forces?
- Friction
- Air / Water resistance (drag)
- Normal contact (reaction)
- Tension
- Upthrust
Examples of non-contact forces?
- Gravity
- Magnetic
- Electrostatic
What happens when the resultant force on an object is zero?
The object remains stationary or continues to move at a constant speed and in the same direction.
What is enersher?
The idea that without an unbalanced force, nothing will change in terms of speed, direction etc.
What is Newton’s 1st law of motion?
An object will remain at rest or at a constant velocity unless there is a resultant force acting on it.
What is Newton’s 2nd law of motion?
The acceleration of an object is directly proportional to the resultant force and inversely proportional to the objects mass.
What equation shows Newtons 2nd law of motion?
F = m a
What is Newton’s 3rd law of motion?
If object A exerts a force on object B, then object B exerts a force on object A which is equal and opposite.
How is inertial mass defined?
By the ratio of force over acceleration
if an object is more inert then it’s harder to move
What is thinking distance proportional to?
Speed
What is braking distance proportional to?
Speed2
What is thinking distance?
The distance travelled during reaction time.
What is braking distance?
The distance travelled while the brakes are applied.
Why does thinking distance increase?
- the speed increases
* the reaction time increases eg. tiredness, distraction, taken drugs / alcohol
When does braking distance increase?
If the initial speed increases or if the size of deceleration is less.
How is thinking distance decreased?
Friction reduced - wet roads, worn tyres or brakes
How is braking distance decreased?
Larger mass of car (more inertia means its harder to stop)
How is thinking distance shown on a graph?
Area of the rectangle underneath the graph
How is braking distance shown on a graph?
Area of the triangle underneath the graph
Typical speed of walking?
1.5 m/s
Typical speed of running?
12 m/s
Typical speed of driving?
20 m/s
Typical speed of flying?
200 m/s