Forces And Motion Flashcards
Define scalar
Scalar quantities only have a magnitude NO DIRECTION
Define vector
Vector quantities have BOTH a magnitude and direction
Give an example of a vector quantity
Velocity
Give an example of a a scalar quantity
Speed
What does the area under a velocity / time graph represent
The distance travelled by the object
What does a HORIZONTAL LINE show on a distance time graph
No movement
What does a HORIZONTAL LINE show on a velocity time graph
Constant speed
What is the equation for acceleration
Change in velocity ÷ time taken
How would you work out the FINAL SPEED of an object
Final speed = initial speed + (acceleration x time)
What is displacement
Displacement is the distance an object moves in a straight line from a starting point to a finishing point
Displacement is a vector quantity
What is distance
Distance is how far an object moves.
Distance is a scalar quantity.
What is the resultant force
The resultant force is the sum of all of the forces acting on an object.
State the resultant force equation
Resultant force (F) = mass (m) x acceleration (a)
(Newton’s 2nd Law)
What is Newton’s 1st law
Newton’s 1st Law says that the velocity of an object will only change if a resultant force is acting on the object
What does Newton’s 3rd law say
Whenever 2 objects interact, the forces that they exert on (apply to) each other are EQUAL AND OPPOSITE
What is the equation for change in momentum
Change in momentum = force x time
What is the law of conservation of momentum
Momentum cannot be created or destroyed.
So, if two objects collide, the sum of momentum before collision = sum of momentum after collision.
What is the formula for momentum
Mass x velocity
How do safety features in a car reduce the force felt by a person in a crash
When a crash takes place, there is a certain change in momentum.
The force felt by the person is the change in momentum divided by the time taken.
Safety features of a car increase the time taken for the momentum to change.
Therefore reducing the force felt by the person in the crash.
What is inertia
A measure of how difficult it is to change the object’s motion.
What is the equation for weight
Weight = mass x gravitational field strength
What is the average value for acceleration on Earth due to gravity?
10m/s^2
What is the definition of weight
The force acting downwards on an object due to gravity
For an object in circular motion, what is the name of the resultant force, acting towards the centre of the circle?
Centripetal force
