Physics - OCR gateway GCSE Triple P2

how to measure very small leangths

screw micrometre

term for when your eyes and the scale are not lined up and how to avoid it

parallax error - read ruler at right angles

how measure measuring cylinder for volume

from the bottom of the meniscus

Equation for average speed

total distance/total time

Scalar

magnitude

Vector

A quantity that has magnitude and direction

Displacement

Distance and direction of an object's change in position from the starting point.

equation for acceleration

vf-vi/t

SUVAT 1

v2 - u2 = 2as ((Final speed)2 - (initial speed)2 = 2 × acceleration × distance.

SUVAT 2

(Distance = (initial speed x time) + ½ (acceleration x time squared)

s = ut + ½ a t2

SUVAT 3

(Final speed = initial speed + (acceleration x time)

v = u + at

distance-time graph

flat line = stationary

constant speed =straight line

gradient = speed

velocity time graphs

flat line = steady velocity

constant acceleration = straight line

area under = distance

counting squares method to calculate curved area under v-t graph

count squares then times it by distance represented by one square

velocity

displacement/time

non-contact force

a force that one object can apply to another object without touching it

contact force

a push or pull on one object by another that is touching it

Newton's First Law

An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force

Newton's Third Law

whenever 2 objects interact, the forces that they exert on (apply to) each other are equal and opposite.

Newton's Second Law

F=ma

free body diagram

a diagram showing all the forces acting on an object

components of forces

a diagonal force can be split into vertical and horizontal forces - this can be calculated using trig

Work done

When a force moves an object, energy is transferred and work is done

Work done (J or Nm) equation

force x distance

More work is done if you:

push with the same force for a longer distance.

or push with a larger force for the same distance.

power

rate of energy transfer (or work done)

(The faster that energy is transferred (or work is done), the higher the power.)

power equation

W/t

Inelastic deformation

An object undergoing inelastic deformation will not return to its original shape once the forces being applied to it are removed.

elastic deformation

will return to its original shape when the force is removed

The Limit of Proportionality (Extension-Load Graph)

where it stops obeying hooks law and curves

Hook's Law

F = kx

Spring extension

force applied/ spring constant

Investigating Hooke's Law- PRACTICAL PART 1

(Set up the apparatus as above.) 1. measure the original length of the spring. 2.hang different masses on the spring and measure the length of the spring in each case

Investigating Hooke's Law- PRACTICAL PART 2

3.Adding masses to the spring increases the downwards force.extension of the spring = length of the spring with masses − original length of the spring.

4. Plot a graph with extension of the spring on the x axis and force on the y axis.

work done on a spring

when compressed, elastic potential energy is stored

calculate EPE from graph

the area under the force-extension graph.

Elastic Potential Energy Stored in a Spring equation

E = ½ k e^2

Inertia

how difficult it is to change the object's motion.

what type of objects have a gravitational field

all

Weight equation

W=m x gfs

What is the value of acceleration due to gravity at the Earth's surface?

9.81 m/s^2

momentum

p = mv

change in momentum

force x time

the law of conservation of momentum

momentum cannot be created or destroyed but transferred

change in momentum 2

mv - mu (where m is mass, u is the initial velocity of an object and v is the final velocity of an object.)

where does the resultant force act on when an object is moving in a circle

the centre, the object is accelerating towards the centre of the circle

an object in free fall will accelerate at...

a constant rate -it is called the acceleration due to gravity (g).

graphs of motion with air resistance

increase in speed causes an increase in air resistance, which opposes the motion

terminal velocity

the highest constant velocity of a falling object when air resistance is equal to the opposite force on the object

Moment equation

force x distance

The principle of moments states that for an object to be in equilibrium...

the sum of clockwise moments = the sum of all the anti-clockwise moments( about pivot point.)

levers and gears

transmit (send) the rotational effect of a force from one place to another

what is pressure measured in

Pascals

Pressure equation

force/area

simple hydraulic system