GENERAL PHYSICS except pressure

Which different instruments are used to measure length

1. Rulers measure small distances of a few centimeters 2. Tape measure is used to measure lengths of a few centimeters 3. Trundle wheel is used to measure lengths of tens of meters 4. Vernier Caliper is used to measure diameter of small objects in mm

How can u measure time

1. Stop watch 2. Light gates, timer starts when first object cuts light beam one and ends when it cuts light beam 2

Which part of the meniscus do you measure the volume of the liquid and why?

Bottom - other part is negligible

What is one oscillation

The time for a pendulum to swing back and fro and return back to its position

How can you accurately measure a small value

Take the value of multiple duplicates of the value and then find the average

How do you make sure something is horizontal

Use ruler with set square to make sure the ruler is perpendicular to the bench. Measure the height of the ruler from the floor and check if they are the same. If they are, the ruler is perpendicular

Describe Displacement Method to Find Volume

1. Partially fill measuring cylinder 2. Measure initial volume 3. Completely submerge object 4. Measure new volume 5. Find difference

How do you measure Mass

Electronic Balance or Beam Balance

How do you accurately find the time for one oscillation

1. Use stopwatch to measure multiple oscillations 2. Use fiducial to know when one oscillation has happened 3. Then find the average so you get the time for one oscillation

Fiducial

Point used for reference

Scalars

Have magnitude only, no direction

Vectors

Magnitude and direction

Scalar Quantities

Distance, Speed, Time, Mass, Energy, Temperature

Vector Quantities

Force, Weight, Velocity, Acceleration, Momentum, Electric Field Strength, Gravitational Field Strength

How do you find the resultant of 2 vectors

Draw a scale diagram of the two displacements end to end, and measure the overall displacement

Speed

Distance / Time

Speed symbol equation

v = s/t

Velocity

Speed in a given direction

Distance Time Graph Acceleration

Curve curving upwards (increasing gradient)

Distance Time Graph Constant Speed

Straight diagonal line upward

Distance Time Graph Deceleration

Curve flattening out (decreasing gradient)

Distance Time Graph Stationary

Flat horizontal line

Velocity Time Graph Increasing Acceleration

Curve curving upwards

Velocity Time Graph Decreasing Acceleration

Curve flattening out towards top

Velocity Time Graph Decreasing Deceleration

Curve flattening out towards bottom

Velocity Time Graph Increasing Deceleration

Curve steepening downwards

Velocity Time Graph Stationary

Flat line at zero velocity

Velocity Time Graph Constant Speed

Flat horizontal line above zero

Velocity Time Graph Constant Acceleration

Straight diagonal line sloping upwards

Velocity Time Graph Constant Deceleration

Straight diagonal line sloping downwards

Speed in a Distance Time Graph

Gradient

Distance in a Velocity Time Graph

Area under the graph

Acceleration

Change in speed per unit time

Acceleration Symbol Equation

a = delta v / delta t

Acceleration in velocity time graph

Gradient

Deceleration

Negative acceleration

Describe the motion of objects falling in a uniform gravitational field with air resistance

1. Initially the object accelerates due to its weight 2. Slowly it starts to accelerate less as the air resistance increases 3. Then the air resistance and the weight balance out and the object reaches its terminal velocity and falls at a constant speed with no acceleration

Describe the motion of objects falling freely under a uniform gravitational field without air resistance

It would keep accelerating

In a Speed time graph in the calculation always write distance as

Area under Graph

On a distance time graph in calculations always describe the speed as

The gradient of the d-t graph

Explain which feature of a speed time graph shows acceleration

The gradient, gradient is speed/time like acceleration

S.I unit of speed

m/s

S.I unit of time

seconds

S.I unit of acceleration

m/s^2

Mass

The quantity of matter in an object at rest relative to the observer

Weight

The gravitational field on an object which has mass

Gravitational field strength

Force per unit mass

S.I unit of Mass

kg

S.I unit of Weight

Newtons

S.I unit of Gravitational field strength

N/Kg

How much is the Acceleration of an object falling freely under earth's gravity

9.81 m/s^2

The gravitational field strength of an object near the Earth

9.81 N/kg

How do you measure Mass vs how do you measure Weight?

You measure mass with an electronic balance or beam balance, you measure weight with a newton meter or spring scale

Inertia

Reluctance of mass to changes in velocity

More mass means __________ inertia meaning more _______

More, resistance

Acceleration calculation image question

500 m/s^2

How do you derive a = g in a vacuum with gravitational force

1. F = ma 2. In a vacuum Weight is the only force so W = ma 3. W = mg so mg = ma 4. g = a

How much time would u use for the deceleration when described as "Immediately"

Immediately means less than 1 sec

Density

Mass per unit volume

Weight formula

W = mg

Derive that m/s^2 = N/Kg

F = ma, 1N = 1 kg x 1 m/s^2, N/kg = m/s^2

Density formula

p = m/v

Substances which are less dense on another substance which is more dense will

Float or go to the top

S.I unit of density

g/cm^3

Why do ships float on water

1. The ship has air space 2. The density of the whole ship is less than the water

Why is it more accurate to measure multiple lengths rather than one

1. Reduces uncertainty 2. The diameter of the x may be different

Why is it more accurate to measure multiple times rather than one

1. More reliable average 2. Less impact of human reaction time

How can you measure a not perfectly straight object with a ruler

Place object on paper and mark the edges on the paper with a pencil and measure the gap

Possible sources of inaccuracy using measuring cylinder

Graduation marks too large

When calculating resultant vectors when do you use cos

When the angle is in between the 2 sides

When calculating resultant vectors when do you use sin

When the angle is not in between the 2 sides

How may forces change an object

1. Change in size 2. Change in shape

How can Resultant forces change the motion of an object

1. Change the speed of the object 2. Change the direction of the object

What is the resultant Force

Overall / Net force

Newton's First Law

An object either remains at rest or continues at a constant velocity unless acted upon by a resultant force

Solid Friction

Force between 2 surfaces which impedes motion and produces heat

Which force acts upon an object moving through a Liquid

Drag (friction)

Which force acts upon an object moving through a gas

Drag (friction) e.g. air resistance

Spring Constant

Force per unit extension

Hooke's Law equation

k = F/x (F is force, x is extension, k is the spring constant)

Limit of proportionality

The point at which the force is no longer proportional to the unit extension

Center of load image question

Mark the center of the load

Apparatus needed for spring constant experiment

1. Spring 2. Clamp stand 3. Metre ruler 4. Set square 5. Fiducial marker

Method for setting up apparatus spring constant experiment

1. Place clamp stand on flat level bench 2. Attach clamp to stand which is holding the spring 3. Clamp the metre ruler vertically next to the spring 4. Use set square to make sure ruler is perfectly vertical 5. Hook mass hanger onto the spring 6. Tape a fiducial marker horizontally to the bottom of the spring

Precautions taken for spring constant experiment

1. Use set square to ensure the ruler is perfectly vertical 2. Avoid parallax error by making sure to read the ruler at eye level 3. Make sure the load is still before taking a reading 4. Repeat for different loads

Method of spring constant experiment

1. Measure the initial length of the spring with no masses 2. Add a 100g mass to the hanger 3. Measure new length 4. Calculate new extension 5. Repeat with increased masses in increments of 100g 6. Remove masses and make sure spring returns to initial length 7. Plot load extension graph

Newton's Second Law

F = ma (F is resultant force, m is mass, a is acceleration Force and acceleration are in the same direction)

Centripetal Force

The force pulling towards the center of a circle causing a change in direction. It acts perpendicular to the direction of motion

Centripetal force of a car turning a corner

Friction

Centripetal Force of a length of string

String Tension

Centripetal force of a planet in orbit

Gravitational Force

Centripetal Force Formula

F = (mv^2) / r

What is the resultant force in circular motion

The centripetal force

Relative to the motion, which direction is centripetal force

Perpendicular towards the center

Which direction is the acceleration in circular motion

Towards the center

Moment of a force

Measure of its turning effect

Moment formula

Force x perpendicular distance from pivot

When is an object in equilibrium

1. No resultant force 2. No resultant moment

S.I unit of Moments

Nm

Center of Gravity

The point where all the weight of an object can said to be concentrated