Physics Forces and Motion Flashcards
Def Scalar Quantities
Have a size but no direction
Eg mass, speed, distance, energy, temperature
Def Vector Quantities
Have a size and a direction
Eg force, weight, velocity, displacement, acceleration, momentum
Speed equation
Speed=distance/time
S=d/t
Distance/time graphs meanings
Slanted straight line - constant speed
Upward curve - Accelerating
Downwards curve - Deccelerating
Perpendicular straight line - stationary
Acceleration equation
Acceleration=change in velocity/time
a=(v-a)/t
Final velocity equation
v^2=u^2+2ad
Velocity/time graphs
Velocity at zero = stationary
Sloping line = acceleration/deceleration
Straight line = constant speed
Force equation
Force = mass * acceleration
Inertial mass
Measurement of how difficult it is to change velocity defined as the ratio force/acceleration
What does negative force mean
It is slowing down moving forward
Def Mass
Mass is the measure of the amount of matter in the object
Def Weight
Weight is the force that the object experiences due to its mass and the gravitational field
Weight equation
Weight = mass * gravitational fields strength
Def Momentum
It is the tendency of an object to keep moving, how difficult it is to make something stop. The momentum of a moving object depends on its mass and its velocity. It is a vector quantity
Def Force
Force is the rate of change of momentum
Momentum equation
Momentum = mass * velocity p = m * v
Force equation 2
Force = change in momentum / time
F=mv-mu/t
F=m(v-u)/t
Deceleration in cars
When the mass or force of the deceleration of a vehicle is large. There are safety features such as seat belts and crumple zone
Changing the size of force
Increasing time increases what m(v-u) is divided by, which reduces force.
Action and Reaction
Newton’s third law states that for every action there is an opposite reaction. If you push a wall the wall exerts the same force back so they are in equilibrium. Need to be on different objects
Conservation of momentum
The total momentum before is the same as the momentum after
Def Stopping distance
Thinking distance + Braking distance
Thinking distance
Thinking distance is the distance it takes for the driver to react to the situation and hit the brakes
Braking distance
Braking distance is the distance it takes for the vehicle to come to a halt
Things that affect thinking distance
Age
Alcohol
Drugs
Things that affect braking distance
Road conditions
Vehicle
Weather
