forces and motion

describe the effects of forces between bodies such as changes in speed

if the net force on an object is not zero, it will accelerate (speed up) or decelerate (slow down)

describe the effects of forces between bodies such as changes in shape

a force can make an object change the direction it’s moving, even if its speed stays the same

describe the effects of forces between bodies such as changes in direction

forces can also deform objects — squash, stretch, bend, or twist them.

if the object returns to its original shape, it’s an elastic deformation (like a spring).

if it doesn’t return, it’s inelastic deformation (like modeling clay)

how do vector quantities differ from scalar quantities ?

is force and vector or scalar quantity ?

vector quatatity

what is the force that opposes motion ?

friction

what is the stopping distance ?

what is the thinking distance ?

what is the braking distance ?

how to calculate the stopping distance ?

what are the factors that affect a vehicle’s stopping distance ?

what is a distance ?

how far an object moves

a scalar quantity (no direction needed)

measured in metres (m)

what is a displacement ?

the distance an object has moves from its starting point

a vector quantity (needs direction)

measured in metres (m)

formula for speed

speed = distance / time

formula for velocity

velocity = displacement / time

definition for acceleration

the change in speed (or velocity) over time

maybe be negative as the object may be slowing down - negative acceleration is called deceleration

units of acceleration: m/s2

formula for acceleration

acceleration = v-u / t

what are the 3 types of force ?

push, pull, turning

what are all forces measured in ?

newtons (N)

what 3 things can a force change ?

speed, direction, shape

what is a scalar quantity ?

it only has a magnitude

what is a vector quantity ?

has a magnitude and direction

list the scalar quantities

mass

power

energy 

time

distance 

speed 

frequency

temperature

work, energy

voltage

list the vector quantities

acceleration

force

velocity

displacement

momentum

what is a resultant force ?

when a number of different forces act on a single object, they combine to act like a single force

what do forces do they were in the same direction ?

add

what do forces do they were in the opposite direction ?

subtract

what is a contact force ?

when two objects must “touch” or “collide” for the force to transfer

what is a non-contact force ?

does not need a physical interaction for the force to be felt

list the contact forces

friction

tension

air resistance 

reaction 

list the non-contact forces

gravitational forces

electrostatic forces

magnetic forces 

what is gravity ?

a force that is produced by anything that has a mass

the bigger the mass the larger the gravity

the further away two objects with mass are, the smaller the gravitational pull

what does the mass tell us ?

how much matter is contains

what is weight ?

the force of gravity that pulls different masses towards each other 

what is mass measured in ?

kg

what is weight measured in ?

newtons

what is the gravitational field strength for every kilogram of mass on earth ?

9.8N / kg or 10N / kg

what is the formula for an object’s weight ?

weight = mass x gravitational field strength

what is streamlining ?

when an object moves through a fluid (air or water)

resistive forces act against it

what will a streamlined object do to the force of resistance?

it will lessen the force of resistance

what is newton’s first law ?

an object will continue to stay stationary or to travel at a constant velocity until an unbalanced force is applied to it 

what happens when an unbalanced force is applied to an object ?

it will either:

accelerate / decelerate 

change direction 

what is newton’s second law ?

the size of acceleration that an object will experience is directly proportional to the size of the resultant force applied 

what does directly proportional look like on a graph ?