Physics January 2020 PPE Flashcards
What is Newtons first law?
If the resultant force on a stationary object is zero, the object will remain stationary. If the resultant force on a moving object is zero then the object will continue to move at the same velocity.(Same speed and direction)
What formula describes Newtons second law?
F = m * a
Force (N) = Mass (kg) * Acceleration (m/s²)
What different forms can acceleration be?
Starting, Stopping, Speeding up, Slowing down, Changing direction
What is acceleration proportional to?
Resultant force
What does a distance/time graph show?
How far something has traveled
What does a velocity/time graph show?
How an object’s velocity changes over time
What does a curve mean on a velocity/time graph and a distance/time graph?
Changing acceleration
What is inertia?
The tendency for motion to remain unchanged
What does inertial mass measure?
How difficult it is to change the velocity of an object
What 3 factors affect inertial mass?
Force
Mass
Acceleration
If 2 objects push off of each other, both with different masses, which would accelerate more?
The object with the smaller mass
How do you calculate momentum?
P = m * v
Momentum (kg m/s) = mass (kg) * velocity (m/s)
Is momentum a scalar quantity or a vector quantity?
A vector quantity. It has size and direction
What is conservation of momentum?
When the total momentum before an event (eg. a collision) is the same as after the event
How do you find speed from a distance/time graph?
The speed is the gradient so
change in vertical / change in horizontal
What is the weight of a 25kg mass on Earth?
25 * 10 = 250N
What is the force that keeps something moving in a circle called?
Centripetal force
If an object is moving in a circle, which way does the force act towards?
The centre of the circle
What is the velocity of an object moving at a constant speed in a circle?
The velocity is constantly changing as it is constantly changing direction
What is the gravitational field strength of Earth?
10N/kg
How do you calculate weight?
Weight = mass * gravitational field strength
Why is mass different from weight?
Weight is the force on an object due to gravity.
Mass is a scalar quantity
What is a scalar quantity?
A physical quantity that has no direction
What is a vector quantity?
A physical quantity that has a direction
Name 2 scalar quantities
Speed, distance, mass, energy, temperature, time
Name 2 vector quantities
Force, velocity, displacement, weight, acceleration, momentum
define acceleration
Acceleration is how quickly something speeds up
How do you calculate acceleration?
A = ( v - u) / t acceleration = change in velocity / time
What does uniform acceleration mean?
Constant acceleration
Give on example of uniform acceleration
Acceleration due to gravity
