Forces and Motion Flashcards
What the equation for speed?
Distance divided by time
What is the difference between speed and velocity?
Speed - how fast
Velocity - direction specified
What is the equation for acceleration?
Change in velocity divided by time
On a distance time graph what is the Gradient Flat section Downhill Curves
Speed
Stopped
Going back to starting point
Acceleration
On a velocity time graph what is the Gradient Flat section Uphill Downhill Curve Area
Acceleration Steady speed Acceleration Deceleration Changing acceleration Distance
What is gravity?
The force attraction between all masses
What is the difference between weight and mass?
Mass - amount of stuff
Weight - different in each planet, mass with gravity
What is the equation of weight?
Mass x gravitational field strength
What are the 7 types of force?
Gravity Reaction force Electrostatic force Thrust, push or pull Drag, air resistance, friction Lift Tension
What does friction do?
Opposes motion of the object - slows down
What 3 ways does friction occur?
Friction between solid surfaces gripping and sliding past each other
Resistance or drag from fluids
Friction increases as the ………………….
Speed increase
What is terminal velocity?
Maximum velocity
When the resistance force is equal to the accelerating force
The terminal velocity depends on ……………..
Their shape and area
What is the first law of motion?
If forces are balanced it will stay still unless moving and will stay the same velocity
What is the second law of motion?
If there is a unbalanced force then the object will accelerate in that direction
What is the equation for force?
Mass x acceleration
What is the third law of motion?
If object A exerts a force on object B exerts the exact opposite force on object a
Momentum before collisions is equal to momentum after
What is a vector and scalar quantity?give examples
Vector - size and direction , force velocity acceleration
Scalar - only size , speed, time, length
What is thinking distance affected by?
How fast
Alcohol, tiredness, drugs
What affects breaking distance?
How fast
Mass of be vehicle
Brakes
Grip
What is the equation for momentum?
Mass x velocity
Momentum before =
Momentum after
What is the equation of force acting?
Change in momentum divided by time taken for change
What is the equation for moments?
Moment=force x perpendicular distance from pivot
Where does the centre of gravity hang?
Directly below the point of suspension
If a object is balanced Total anti-clockwise moments =
Total clockwise moments
If the moments are not equal there will be
A resultant force
What is hookes law?
Extension is proportional to force
What is the length of an I stretched metal wire called?
Natural length
When does hookes law stop working?
When the force is great enough
What is the universe?
A large collection of billions of galaxies
What causes orbit?
Gravity
How do comets orbit the sun?
Elliptical with sun at the focus
When does a comet travel faster?
By the sun
What are the different types of forces?
Gravitational Reaction Electrostatic Thrust (push / pull) Lift Tension Air resistance Water resistance
What is the difference between vector and scalar quantities?
A scalar has a magnitude of size only e.g. Speed 10m/s
A vector has a magnitude of size and direction e.g. Velocity 10m/s East / force 50N left
Is force a vector or scalar quantity?
Vector
What is friction?
A force that opposes motion
What is the equation for the relationship between force, mass and acceleration?
Force = mass x acceleration
What is the equation for the relationship between speed, distance and time?
Speed = distance / time
What is the equation for the relationship between acceleration, change in velocity and time?
Acceleration = change in velocity / time
What is the equation for the relationship between momentum, mass and velocity?
Momentum = mass x velocity
What is the equation for the relationship between moment, force and distance?
Moment = force x perpendicular distance to pivot
What is the area under a distance time graph?
IGNORE
The speed
