everything Flashcards
what is a straight line?
constant speed
what is a less steep line?
lower constant speed
what is a flat/horizontal line?
stationary
what is the equation for stopping distance?
thinking distance + breaking distance
what are the features of impairing thinking distance?
- alcohol
- tiredness
- visibility
what are the impairments of breaking distance?
- weather : icy road (increase) dry road (decrease)
- brake pad quality
- road conditions
what is resultant force?
the force produced after forces are balanced.
name some forces.
gravity (weight), air resistance, friction, push pull.
what is newtons 1st law?
inertia: an object will remain at rest or in uniform motion in a straight line unless acted upon by an external resultant force. (tendency of objects to keep moving in a straight line at constant speed.)
what is newtons 2nd law?
the rate of change of momentum is proportional to the (resultant) force applied, and takes place in the direction of the (resultant) force. resultant force = mass x acceleration
what is momentum?
momentum is a measure of the ‘amount of motion’ in a body/object. the effect of the force on the velocity of a body depends upon the size of the force and upon the mass of the body.
equation for momentum?
mass x velocity
what is force?
a change in momentum/time.
the bigger the ____ the _____ the effect?
force/greater
the _____ the body’s mass the smaller the effect on the body’s _______ .
bigger/speed or velocity
what is newtons 3rd law?
if a body A exerts a force on a body B then body B exerts an equal and opposite force on body A.
an object can possess energy because of its motion (_____) or position (_____) or deformation (_______).
kinetic energy/gravitational potential energy/elastic energy
at the top of a rollercoaster there is _________ and low ________. at the bottom of a rollercoaster there is low __________ and ___________ .
high gravitational potential energy/kinetic energy/gravitational potential energy/high kinetic energy
what is work done?
quantity of energy transferred by the force to move an object
what is the work done equation?
work = force x distance
what is terminal velocity?
the fastest possible speed it is going
state the skydiver qer.
- one force which is his weight pushing him down
- as he travels faster, the air resistance increases
- 2 forces become equal. moving the skydiver travels at a constant speed. this is terminal velocity.
- air resistance increases. resultant force is upwards. this makes him slow down.
- 2 forces become equal. there is no resistant force and travels at a constant speed. this is his new terminal velocity.
- when he hits the ground, it pushes up against him for him to decelerate quickly. upwards force is equal to his weight. there is no resultant force
