Impulse & Momentum (hardest 400 & 500)
Electrostatics & Electromagnets
Circuits
Waves - General
Light
100
When two objects collide elastically the momentum is conserved. Describe what happens to momentum when two objects collide inelastically.
Momentum is also conserved.
100
A negatively charged rod is brought close to a neutrally charged metal sphere. Describe what happens to the electrons in the metal sphere.
They move to the opposite side but overall, the charge does not change since no electrons are transferred.
100
If I had the following circuit, how would I change the connection to make each bulb brighter?
Add more wires and make it parallel!!
100
Which letter is the amplitude?
C.
NOT B!!
100
If the person is looking into a plane mirror, which letter represents where the virtual image would appear?
Location C
200
A race car with a mass of 50 kg clears the school's track in 3.5 seconds with a constant velocity of 1400 m/s. What is the race car's momentum?
p = mv = 50 x 1400 = 70,000 kg m/s
200
What is this? Describe what it is used for.
It is a step up transformer used to increase voltage.
200
Calculate the total current in this circuit.
I = V/R
Since series, just add resistors.
I = 9 / 450 = 0.02 amps
200
What does it mean for a wave to have "harmonic motion"?
The wave repeats in regular intervals/periods.
200
What is the main similarity between sound waves and light waves?
They both transfer energy.
300
Calculate the change in momentum of a 1,200 kg car if it accelerates with a force of 50 N over 3.5 seconds.
J = Ft = mv
Change in momentum = either section
So Ft = 50 x 3.5 = 175 N s
300
A negatively charged balloon is brought close to a metal sphere. The sphere is then touched. Describe what happens to the electrons in the metal sphere.
The electrons initially move away from the balloon. When the sphere is touched, the electrons "escape" through the person's hand and into the ground, leaving an overall positive charge on the sphere.
300
There are 2 resistors connected in the circuit shown. Each resistor has a resistance of 3 ohms. What would happen to the total resistance if another 3 ohm resistor were added, as shown in the image?
The overall resistance would decrease
- There are more paths now!
300
Why do astronauts often choose to use radio telescopes?
The light from most celestial objects is red shifted, a radio telescope is able to detect longer wavelengths and see through dust/clouds.
300
A beam of light passes through a double slit and forms a pattern of bright and dark bands on a screen.
What causes the pattern to appear?
Interference - Constructive and Destructive
400
A grocery shopper tosses a 9.0 kg bag at a velocity of 5.5 m/s. If the bag lands in a stationary 18.0 kg grocery cart, what is the final velocity of the cart?
2.75 m/s
400
A negative charge of -1.5 x 10-4 C and a positive charge of 8.0 x 10-4 C are separated by 0.25 m. What is the magnitude of the force between the charges?
Fe = 8.63 x 103 N
400
Calculate the equivalent resistance in the circuit.
Parallel so...
1/((1/20)+(1/100)+(1/50))=12.5
400
Draw and correctly label a diagram of what the doppler effect does to a sound wave's frequency.
400
Based on the object's location, where would an image form on the other side? Also describe its size and where it is virtual or real.
Since the object is beyond 2f, the image forms in between 1-2F on the other side. It forms a real minimized image.
500
A 7.0 kg ball rolls down a lane at 8.0 m/s and hits a 1.5 kg pin. If the pin went flying at 14 m/s, what was the final velocity of the ball?
5 m/s
500
When two charged spheres are separated by a distance of r , they exert a force of 54 N on each other. What force would they exert on each other if the distance between them was tripled?
Inverse - Square Law - They would experience 1/9th the force so 54/9 = 6N.
500
Find the total current flowing through the circuit below if R1 = 15Ω, R2 = 15Ω, R3 = 5Ω and the battery’s potential difference (voltage) is 15V?
Req = 3
Current = V/R = 15 / 3 = 5 amps
500
Calculate the velocity of the following wave if it has a frequency of 10 Hz. 
v = f * lambda
= 10 * 9 = 90 m/s
500
A solar panel works by using the light from the Sun to generate an electrical current. However, it only works with light that has a higher frequency than 750 THz. What is this an example of? And what does this suggest about the nature of light?
This is the photoelectric effect, that suggests light is a particle.