Overall Flashcards
What is meant by displacement?
Displacement is defined as the change in position of an object.
What is a vector quantity?
A quantity that has both magnitude and direction.
What is a scalar quantity?
A quantity that has magnitude but no direction.
How do you represent a vector quantity?
Tip to tip
Head to head
Tip to head
What is a resultant force?
When forces are acting on an object in two DIFFERENT directions, the DIFFERENCE between the forces is called the resultant force.
When forces are acting on an object in the SAME direction, the resultant forces is the SUM of those forces.
What happens if the resultant force is zero?
The object is stationary or moving at a constant speed
What is a free body force diagram?
It models the forces acting on an object.
What is the parallelogram of forces?
A parallelogram that has two adjacent sides that represent two force vectors and a diagonal line between them that represents the vector (force) sum.
What is the parallelogram of forces used for?
The parallelogram of forces is a method for solving the results of applying two forces to an object.
What is meant by resolution of a force?
A single force can be resolved (broken down) into two component forces at right angles to each other.
What is net force?
The net force is the vector sum of all the forces that act upon an object.
What are forces on an object in equilibrium?
If the size and direction of the forces acting on an object are exactly balanced, then there is no net force acting on the object
How do you use a force diagram to tell whether an object is in equilibrium?
The arrows are balanced/same size.
How do you calculate speed?
SPEED = DISTANCE/TIME
How do you calculate acceleration?
ACCELERATION = CHANGE IN VELOCITY/TIME
What does the gradient of distance time graphs show?
The gradient of the line is equal to the speed of the object.
How do you calculate constant speed?
time taken
What is the difference between velocity and speed?
Speed is how fast something is moving. Velocity is how fast and in what direction.
What is acceleration?
The rate at which velocity changes with time.
What is the difference between acceleration and deceleration?
Acceleration is the rate at which velocity changes with time.
Deceleration is acceleration that causes a reduction in speed (negative).
What is newton’s law of motion?
- An object will not change its motion unless a force acts on it.
- The force on an object = mass x acceleration.
- When two objects interact, they apply forces to each other of equal magnitude and opposite direction.
What is the equation that links force, mass and acceleration?
FORCE = MASS X ACCELERATION
How does the acceleration of an object depend on the size of the resultant force acting on it?
The acceleration of an object is proportional to the resultant force on the object.
What is inertia?
The resistance an object has to a change in its state of motion.
What is the equation for final velocity?
Final velocity squared = initial velocity squared + 2(acceleration x time)
V2 = U2 + 2AS
What is the difference between mass and weight?
Mass is a measure of how much matter there is in an object, while weight is a measure of the size of the pull of gravity on the object.
What is the motion of falling objects?
An object that is moving only because of the action of gravity is said to be free falling (not much air resistance).
What is terminal velocity?
Steady speed achieved by an object freely falling.
What is the resultant force acting on an object falling at terminal velocity?
Zero.
What does the stopping distance of a vehicle depend on?
The speed of the car
The mass of the car
How worn the brakes and tyres are
The road surface
What are some car safety features?
Seat belts, air bags, brakes.
How do you calculate work done with kinetic energy?
WORK DONE = CHANGE IN KINETIC ENERGY
How can you calculate work done?
WORK DONE = FORCE X DISTANCE
What is electric charge measured in?
Coulombs.
What is the formula for braking force?
BRAKING FORCE = WORK DONE / DISTANCE
How do you calculate momentum?
MOMENTUM = MASS x VELOCITY
What is the unit for momentum?
Kg m/s
What does momentum mean for a closed system?
Momentum is constant in time (conserved).
What happens when two objects collide (momentum)?
The force exerted by object 1 upon object 2 is equal in magnitude and opposite in direction to the force exerted by object 2 upon object 1.
What quantity is momentum?
Vector.
What happens to the total momentum of two objects when they collide?
The momentum stays the same the whole way though.
Why do two objects that push each other apart move away at different speeds?
One object gains momentum and one loses momentum.
What is meant when an object is called elastic?
The ability of a deformed object to return to its original shape and size when the forces causing the deformation are removed.
What is the elastic limit of an object?
The furthest amount an object can be stretched or deformed without being able to return to its previous shape.
How do you measure the extension of an object?
EXTENSION = FORCE / SPRING CONSTANT
How does the extension of a spring change with the force applied to it?
The extension of a spring is directly proportional to the force applied.