Topic 2 Flashcards
What must always be true when using the SUVAT equations of motion?
The acceleration must be unifrom - if the acceleration is changing, the equations are not valid.
What does the gradient of a distance-time graph represent?
Speed
What does the gradient of a displacement-time graph represent?
Velocity
What does the gradient of a velocity-time graph represent?
Acceleration
Describe the shape of a velocity-time graph for an object travelling with unifrom acceleration.
If accleration is constant, the gradient of the velocity-time graph will be constant and so it will form a straight line graph.
Describe the shape of a velocity-time graph for an object travelling with non-uniform acceleration
If acceleration is not constant, the gradient of the velocity-time graph will change and so it will form a curve
Compare the velocity-time graphs for a uniformly accelerating and a uniformly decelerating object.
For an accelerating object, the gradient will be positive
For a decelerating object, the gradient will be negative
What is a scalar quantity
A scalar quantity is one that has a magnitude but not a fixed direction
What is a vector quantity
A vector quantity is one that has a magnitude and a fixed direction
Give five eamples of scalar quantities
Distance, Speed, Mass, Energy, Temperature
Give five examples of vector quantities
Displacement, Velocity, Acceleration, Momentum, Force
How is a vector quantity represented on a diagram?
As an arrow,
The direction of the arrow represents the direction of the quantity,
The length of the arrow represents the magnitude of the quantity
What does resolving a vector involve?
Splitting the vector into two perpendicular components, vertical and horizontal.
Define the horizontal component of the vector in terms of V and θ
x = Vcos(θ)
Define the verticle component of the vector in terms of V and θ
y = Vsin(θ)
Describe the relationship between the perpendicular components of a vector
The perpendicular components are independent of each other
How should the components of a projectile be handled when carrying out calculations
The horizontal and vertical components are independent of each other and so should be treated separately
SUVAT should be used separately for each component
If a projectile is moving freely under gravity, what can be said about the vertical acceleration?
The vertical accelaration will be the acceleration due to gravity and so will have a magnitude of 9.81m/s^2
State Newton’s first law of motion in words
An object at rest will remain at rest, and an object moving with a given velocity will continue moving with that same velocity, unless acted on by an external resultant force.
State Newton’s second law of motion in words
The acceleration of an object is directly proportional to the resultant force acting on it and inversely proportional to its mass.
State the defining equation of Newton’s second law of motion.
F=ma
Force (N) = Mass (kg) x Acceleration (m/s^2)