P2 Flashcards
What is the primary measurement for speed and velocity?
M/S
What is the difference between speed and velocity?
speed is how fast. you are going, velocity takes into account the direction you are going eg 30 m/s north
how do you calcualte the speed
speed = distance over time
what does the gradient of a distance time graph tell you?
How fast your object is going
how do you find the speed in a dt graph,
gradient
What is a flat section in a dt graph
the object. is stationary
what do straight uphill or downhill slopes mean on a dt graph
the object. is travelling at a steady speed
what do downhill lines mean in a dt graph
that the object is going back to its starting point
what does a steeper graph mean
the object if going faster
what do curves mean in a dt graph
acceleration or decceleration
wht is acceleration
how quickly the velocity is changing
how do you find the acceleration
change in velocity over time taken
what is the gradient in a vt graph
acceleration
what is a flat section in a vt graph
steady soeed
what is a uphill/downhill slope in a vt graph
acceleratikn/deceleration
what does gravitational force do
it makes all things accelerate towards the ground, all with the same acceleration which is about 10 m/s squared on earth
What is the difference between weight and mass
Mass is the ammount if stuff inside an object it is the same anywhere in the universe. weight caused by the pull of the gravitational force
how do you measure mass
kg
how do you measure weight
N
how do you find the weight
mass X gravitational feild streingth
what is the resultant force
if you have a number of forces acting upon a single point, you can replace then with a single force, as lomg as it has the same effect on the motion as the original forces acting all together, of the forces all act upon the same line (theyre all paralel and act in the same opposite direction) the overall effect is found by just adding or subtracting them, the overall force you get is called the resultant force
what dies an object need to start moving
a force
what happens if there is no resultant force on a moving object
there will be no change in velocity and so it will keep moving
what happens if there is a non zero resultant force applied on an object
the object will accelerate in the direction of the force
what is the formula for a resultant force producing acceleration
F = ma
f is the resultant force in newtons
m is the mass in kilograms
a is the acceleration in meters per second squared
what happens when 2 object interact
the forces they exert on each other are equal and opposite
why will an object that has ni force propelling it always stop
because of friction
what directiom does friction always act
opposite to movement
how is most of the resistive force caused?
by drag
what is the most important factor in reducing drag in fluids
keeping the shape of the object streamlined
what causes frictional forces in fluids to increase
speed
wht do falling object accelerate when they first set off
because the force of gravity is much more than the force of frictikn slowing them down, so they accelerate, as the speed increases the friction builds up, this gradually reduces the acceleration until eventually the frictional force is equal to the accelerating force and the. it wont accelerate any more, this is the terminal velocity and it will now fall at a steady speed
what is the accelerating force acting upon all falljng objects and why do some fall at different rates
it is gravity and they fall at different rates due to air resistanc
how it the terminal velocity of an object determined?
its drag in comparison to its weight
what does the frictional force of an object depend on
its shape and area
what is the stopping distance
the distance from an objest to start to stop to it comming to a complete stop
what is thinking distance effected by
how fast you are going
how ‘sharp’ you are
what is braking distance effected by
how fast your going
how good your breaks are
how good the tyres are
how good the grip is
expain how work is done
whenever something moves, some thing else is transferring energy into it, this means that the thing transferring energy needs an energy supply, it then dkes work by moving the object amd one way or another it transferres the energy it receives as fuel as other forms
explain wasted energy
when energy is transferred from one thing to another, some of it is transfered as useful energy but some of it can be wasted eg heat from a tv
what is the formula for work done?
work done = force X distance
how do you find gravitational potential energy and what does g stand for
mass X g X height
g is for the gravitational feild strength, on earth it it 10N/kg
what is the formula for kinetic energy
1/2 x mass x speed squared
show kinetic energy transferred = work done by brakes and what all the letters mean
1/2 x m x v squared = f x d
1/2 x mass x speed squared = maximum breaking force x breaking distance
what is the same as kinetic energy gained
= potential energy lost
what is elestic potential energy
object that can mkve back to their original shape are elastic objects, when an elestic object is moved out of shape, the energy is stored from the work done to it as epe (just ez to type) and when released the energy will be turned to kinetic energy and it will move back to shape
what is the limit of proportionality in term of elastic objects
the maximum force that the elastic object can take and still extend proportionally
what is the formula for power
power = work done or energy transferred over time taken
or p= e over t