Nature of Physics

Question 1

45 °- 45 °- 90 ° Triangle (Isosceles)

Answer 1

Hypotenuse: √2
Horizontal: 1
Vertical: 1

sin 45° = √2/2
cos 45°= √2/2
tan 45°= 1

Question 2

30 °- 60 °- 90 ° Triangle (half equilateral)

Answer 2

Hypotenuse: 2
Horizontal: 1
Vertical: √3

sin 30° = 1/2
cos 30°= √3/2
tan 30°= √3/3

sin 60° = √3/2
cos 60°= 1/2
tan 60°= √3/1

Question 3

Handy approx. decimal numbers

Answer 3

√2= 1.4
√2/2= 0.7
√3= 1.7
√3/2= 0.866
√3/3= 0.577
√10= 3

Question 4

Basic Logarithms

Answer 4

N = b^k<—>b= k√N

N = b^k<—>logb(N)= k

Question 5

Dicebel formula

Answer 5

B= 10 log (I/Io)

Multiplying I by 10^N adds 10N to B.
E.g decibels increase 25. 2.5 added to logarithm. Adding 2 to logarithm means I multiplied by 10^2= 100 and adding 0.5 means I multiplied by 10^0.5 = 3. I multiplied by total 300

Question 6

pH formula

Answer 6

pH= log [H+ or H3O+]

• Multiplying [H+] by 100 will decrease pH by 2
• Multiplying [H+] by 30 will decrease pH by 1.5