Circuits
If current splits and follows multiple paths in a circuit, what type of circuit is it?
Parallel Circuit
What are the longest type of waves?
Radio waves
The kinematic equations tell us about these four variables:
- distance
- velocity
- acceleration
- time
How fast does sound travel in space?
It can't!
Who discovered this law of nature?
Isaac Newton
A circuit has 4 resistors in parallel. What equation do I use to find the total resistance?
1/RT = 1/R1 + 1/R2 + 1/R3 + 1/R4
Which type of wave has the lowest frequency?
Radio waves
What is the final velocity of a car that starts from rest at a stop light, then accelerates at 10 m/s2 for 4 seconds
Vf = 0 + a*t
= 10 m/s2 * 4 s
= 40 m/s
If a police car is driving away from you, how does that effect the pitch of the siren?
Pitch goes down.
If the Earth pulls you down with a gravitational force of 500 N on you, what force do you pull up on the Earth?
500N
A series circuit has a total resistance of 200 ohms. If there are 2 equal resistors in the circuit, what is the resistance on each of them?
100 ohms each.
Which color of light has the highest frequency (shortest wavelength)
Violet
Use Vf = Vi + a*t to show that an object that is not accelerating is going at a constant velocity.
if a = o
Vf = Vi + (0)*t
Vf = Vi (final velocity is the same as the initial velocity, i.e. constant)
In which medium does sound travel the fastest?
In a solid
The Sun is about 1 million times more massive than the Earth. Why is the moon gravitationally bound to the Earth rather than the sun?
Because the Earth is a lot closer. (distance matter more than mass)
Find the Current if a circuit has a total resistance of 45 ohms and a voltage of 45 volts.
I= V/R
= 45V/45ohm
= 1 A
Red light has a wavelength of 700nm, what is its frequency?
f = c/λ
= (3*108 m/s)/(700*10-9m)
= 4.3*1014 Hz
What is the acceleration of Tesla if it can do 0 to 45 m/s (100 mph) in 4.2 s.
Vf = Vi + a*t
Vf - Vi = a*t
a = (Vf - Vi)/t =ΔV/t
= (45 m/s - 0)/4.2s
= 10.7 m/s2 (about 1.1 g of acc)
What is the velocity of sound in the air if it is 72 degrees Fahrenheit ?
° F = 1.8*° C + 32
V = 330 m/s + (.6 m/s/°C * ° C)
°C =(°F -32)/1.8
= (72-32)/1.8 = 22.2 ° C
V = 330 + (0.6 * 22.2)
= 343.3 m/s
Find the force of gravity currently acting on Mr. Beasley. He has a mass of 70 kg.
Distance to center of Earth=6.4 *106 m
Mass of Earth= 6* 1024 Kg
F = (6.67*10-11 *6* 1024 *70)/(6.4* 106)2
= 684 N
or F = mg
= 70kg* 9.8m/s2 = 686N
Find the total Resistance.
(Image 1)
1/R23 = 1/R2 + 1/R3 R23=6 ohm
= 1/24 + 1/8
= 1/24 + 3/24 = 4/24
= 1/6
RT = R1 + R23 = 4 + 6 = 10 ohm
White light passes through a filter that absorbs red and blue. What color is the filter?
Green
Find the initial velocity:
Given: Vf = 2m/s
a = 10 m/s2
d = 25m
Vf2 = Vi2 + 2*a*d
Vi2 = Vf2 + 2*a*d
Vi = (Vf2 + 2*a*d)1/2
= ((2 m/s)2 + 2*10 m/s2 * 25m)1/2
= ( 4 m2/s2 + 500 m2/s2 )1/2
= 22.45 m/s
You are driving towards a firetruck at 10 m/s that is driving towards you at 20 m/s. It's siren is ringing at 650 Hz. What frequency do you hear? It is 0 degrees celsius outside.
f = (v -+ vr)/(v +- vs) *f0
f = (330 + 10)/(330 - 20) * 650
= 340/ 310 * 650
= 712.9 Hz
The sun is being sucked in by a black hole and is orbiting at a million meters from it (106m). If the Gravitational force is 2.6*1047 N and the sun's mass is 1.989*1030 Kg, find the mass of the black hole.
Mbh = (d2*F)/(G*msun )
= 1.989*1039Kg
or a billion suns!!