physics paper 2 revision notes grade 9-1

Topic P5- forces

 work done and energy transfery

when a force causes an object to move, work is done on the object. 

work done= force x distance ( W=Fs)

forces and elasticity

when a object doesn't return back to it's orginal shape it is- elastically deformed

the extenstion of an elastic object is directionally proportional to the applied force

the gradient of the linear section of the graph= spring constant

the are below the graph= work done to streatch or compress the spring

equation: force= spring constant x extenstion ( F= ke)

distance and displacement

distance is a scalar quantity: it is how far an object moves, it doesn't take into the direction an object is travelling.

displacement is a vector quantity: it is how a magnitudem which describes how far the object has travelled from the orgin, measured in a straight line. it has a direction, which is of a straight line.

speed

the speed of an object is a measure of how fast it is travelling. it is measured in metres per second (m/s)

distance travelled = speed x time ( s=vt)

velocity

velocity is a vector quanity. it is the speed of an object in a given direction. when travelling in a straight line, an object with a constant speed also has a constant velocity

newton's first law

newton's first law is an object will remain in the same state of motion unless acted on by an external object

when the resultant force is 0: the object will remain stationary,if the object is moving it continues to move at the same speed ans in the same direction- at a constant velocity

intertia: the tendency for object to continue in the same state of motion 

distance- time graph

a distance time graph can be used to represent the motion of an object travelling in a straight line

a distance time graph can be used to calculate speed

if an object is accelerating the graph will be a curve

time is worked out by- drawing a tangent to the curve at the point in time and then working out the gradient of the tangent

acceleration

the acceleration of an object is a measure of how quickly it speeds up, slows down or changes direction

acceleration= change in velocity divided by time taken

velocity- time graphs

the gradient of a velocity time graph can be used to find the acceleration of an object

the total distance travelled is equal to the area under the graph

newton's second law

newton's second law states: the acceleration of an object is proportional to the resultant force acting on, the object and inversely proportional to the mass object

force= mass x acceleration (f=ma)

mass is the mesure of inertia, the larger the mass the bigger the force needed to change the velocity

terminal velocity

when a object first starts falling, the force of gravity is much larger than the drag slowing it down,the object will fall at a constant speed, this speed…