Class 1

Question 1

What is the density of water?

Answer 1

1 g/cm^3

Question 2

What is elementary electric charge (e)?

Answer 2

1.6 x 10^-19 C

coulombs

Question 3

What is Coulomb’s constant (k0)?

Answer 3

9 x 10^9 Nm^2/C^2

Question 4

What is the threshold of hearing (I0)?

Answer 4

10^-12 W/m^2

Question 5

What is the speed of light (c)?

Answer 5

3 x 10^8 m/s

Question 6

What is the most common pythagorean ratio that pops up?

Answer 6

3-4-5

Question 7

What is the trick for remember ing the cos and sin values for common angles?

Answer 7

(Starting at 0 degrees) Cos counts down; sin counts up

Question 8

What is the square root of 2?

Answer 8

Valentines Day trick!

1.4

Question 9

What is the square root of 3?

Answer 9

St. Patricks day trick!

1.7

Question 10

What is the cos of angles 0, 30, 45, 60, 90, and 180?

Answer 10

cos 0 = (sqr rt of 4)/2

cos 30 = (sqr rt of 3)/2

cos 45 = (sqr rt of 2)/2

cos 60 = (sqr rt of 1)/2

cos 90 = 0

cos 180 = -1

Question 11

What is the sin of angles 0, 30, 45, 60, 90, and 180?

Answer 11

sin 0 = 0

sin 30 = (sqr rt of 1)/2

sin 45 = (sqr rt of 2)/2

sin 60 = (sqr rt of 3)/2

sin 90 = (sqr rt of 4)/2

sin 180 = 0

Question 12

What is the equation for the area of a circle?

Answer 12

A = pi r^2

thus area is proportional to r^2

Question 13

What is the unit of charge?

Answer 13

C, Coulomb

Question 14

What is the value of the metric prefixes?

pico
nano
micro
mili
centi
kilo
mega
giga

Answer 14

pico = 10^-12
nano = 10^-9
micro = 10^-6
mili = 10^-3
centi = 10^-2
kilo = 10^3
mega = 10^6
giga = 10^9

Question 15

If you are turning, is your velocity by definition changing? And what does that also mean must be true?

Answer 15

Yes

If your velocity is changing, you must also have acceleration.

Question 16

How do you find the change in acceleration from 2 velocity vectors?

Answer 16

v + (-v0)

Question 17

Can you have a change in acceleration but a constant speed?

Answer 17

Yes! Turning at a constant speed is a change in velocity and thus in acceleration.

Question 18

What are the kinematic equations?

Answer 18

1. d = 1/2 (v0 + v)t
2. v = v0 + at
3. d = v0t + 1/2at^2
4. d = vt - 1/2at^2
5. v^2 = v0^2 + 2ad

Question 19

What is acceleration when a thrown object is at its apex?

Answer 19

STILL gravity (10 m/s^2)!

Question 20

Is motion in the x direction and y direction independent?

Answer 20

Yes

Question 21

In projectile motion at an angle, what is the initial velocity in the x and y directions?

Answer 21

V0x = cos(theta)
V0y = sin(theta)

Question 22

Do forces in action-reaction pairs cancel out?

Answer 22

No! Even though they are acting in opposite directions, the forces are not acting on the same item and thus forces do not cancel?

The equal is not necessarily the same because the objects might have different masses.

Question 23

What is Newtons first law?

Answer 23

An object at rest (or in motion) will stay at rest (or in motion) unless a force acts upon it.

If Fnet = 0, v will be constant

Question 24

What is Newtons second law?

Answer 24

F = ma

Net force and acceleration are always in the same direction

Question 25

What is Newtons third law?

Answer 25

When objects interact, they exert an equal and opposite force on each other, though they do not necessarily have equal impact.