Chap 4 Mistakes + Uncertainties!!!

Question 1

How to calculate absolute uncertainty if they give you few and ask to find mean ?

Answer 1

Range /2!!!

Question 2

What to remember about finding total uncertainties like volume

Answer 2

Always add ,
do you uncertainty / measure *100

And for volume if it’s r*3 even though r and not diameter multiple uncertainty by 3!!!!

Question 3

What to remember about moments fidantce

‘ don’t get trapped

Answer 3

TAKE THE MIDDLE OF THE OBJECT ITS A TRAP

Question 4

What is principle of moment second mark

Answer 4

FOR A BODY IN EQUIKIBRIUM

Sum of moment anti = clock

Question 5

If they ask what is com what you say if they say where

Answer 5

What = the point where mass thought to be concentrated , point through which if force applied produce no rotational moment

Where = symmetry

Question 6

If centre of mass directly below somethint why would it be

Answer 6

Probably because that means no moment acts if it’s there, as it is pivot

Question 7

What are resolutions of vernier calliper and micrometer ?

Answer 7

Ruler = 1mm
Vernier = 0.1mm
Micrometer = 0.01mm

Question 8

Systematic error vs random human element error for uncertainties ?

Answer 8

Systematic = happens each time and can be accounted for and error constant

Human element = different error each time ‘, not constant

Question 9

Why is resolution used as uncertainty normally

Answer 9

Because the systematic error is actually less than the resolution error

Question 10

How to combine uncertainties

Answer 10

Always add the percentage uncertainties together

If constant multiply constant by it

Question 11

How to reduce systematic error

Answer 11

Calibrate if not calibrated then easily fix,
Remove background radiation
Meniscus etc parallax

Question 12

How to reduce uncertainties

Answer 12

1) measure over larger distance

2) measure using better resolution

Question 13

Uncertainty in readings vs measurements?

Answer 13

Measurements = +- smallest measurement so reading / 2

Readings = +- smallest division

Question 14

Terminal velocity which reaches faster ?

Answer 14

If greater mass then greater eight do greater drag that needs to match

If greater drag then have to have greater velocity and accelerate for longer to hit that

This terminal velocity is greater

Question 15

Define torque of couple

Answer 15

Given by one of the forces multipedid by PERPENDICULAR distance connecting both

Question 16

Define Newton

Answer 16

Newton is the force that needs to be applied to a body of 1 kf to cause it to accelerate 1 ms2