Physics
Final Exam Review
Rotational Motion and Gravitation
1.) Earth has a mass of 5.98 E24 kg and a radius of 6.4 E6 m. If a satellite orbits Earth 295 km from the surface, then what must its velocity be to remain in orbit?
2.) The gravitational force between the Moon and Earth is 3.027 E20 N. If Earth has a mass of 5.98 E24 kg and the center of the moon is 3.8 E8 m from the center of Earth, then what is the mass of the moon?
3.) An axle moves from rest to an angular speed of 5.8 rev./s in 9.0 s. Assuming constant angular acceleration, what is the angular acceleration in rad/s2?
4.) The driver of a car traveling 24 m/s applies the brakes and comes to a stop, undergoing a constant deceleration of 2.6 m/s2. If the tires have a radii of 0.34 m, then:
a) How many seconds does it take for the car to come to a halt?
b) How many revolutions does each tire make before coming to a halt?
5.) A coin with a diameter of 1.2 cm initially rolling along a surface at a rate of 6 rad./s begins to slow with a deceleration of 0.6 rad/s2 until it comes to rest.
a) How long does it take for the coin to come to rest?
b) How many times does it rotate during this time?
6.) Determine the maximum linear velocity that an ice skater can round a curve that has a radius of curvature of 20 m. The coefficient of friction between the skates and the ice is 0.15. Also, determine the time it would take to travel the curve (half a circle) if the skater traveled at a constant velocity.
7.) A ball on the end of a rope has a mass of 0.9 kg. What must the linear velocity of the ball be in order to keep the rope in tension in a straight line horizontal to the ground if the rope is 1.2 m long?
8.) If a planet that has a mass of 5.06 E25 kg orbits a star that has mass of 6.24 E34 kg at an average radius of 4.31 E10 m, then what is the angular velocity of the planet?
Waves and Sound
1.) Using the Doppler Effect, explain why an object moving toward you emits a sound with a higher pitch than an object moving away from you.
2.) Explain why a wave will travel faster through a solid medium than through a gas medium.
3.) Use the Superposition Principle to determine the resultant wave:
4.) Sound travels at a speed of 343 m/s in 20 C air. The wavelength of a particular sound wave is 1.52 m. What is the period of the wave?
5.) What does SONAR stand for?
6.) What does RADAR stand for?
7.) What is the velocity of a jet traveling Mach 2 (vs = 343 m/s in 20 C air) in mph?
8.) An ultrasound wave is emitted at a frequency of 3.4 MHz, reflected off a boundary of different density, and detected 1.2 milliseconds later. If the ultrasound wave is known to travel through a particular medium at 1535 m/s, then:
a) how far way was the boundary it reflected off of?
b) what was the wavelength of the wave?
c) how many times did the wave fully oscillate from the time it was emitted to the time its reflection was detected?
9.) The wavelength of a particular sound wave in air at 20 C s 3.10 m. Considering that the
frequency of a wave does not change as it passes into a different medium, and that sound waves travel 343 m/s in 20 C air and 1497 m/s in water, what will the wavelength of the sound wave be when it passes into a body of water?
10.) Name the categories of the electromagnetic spectrum from lowest frequency to highest frequency.
11.) If a micro wave was transmitted at a frequency of 2.5 E 11 Hz, then what would its wavelength be?
12.) If a radio wave was emitted in the year 2008, what year would it be when a planet 125 light years away received the radio wave?
13.) When an electric current is generated, a magnetic field permeates ___________________ to the charged particle motion.
14.) The _________ determines frequency ranges for radio wave applications.
15.) Why are radio waves used for astronomy if the resolution or image clarity is poor?
16.) Explain how microwave ovens heat objects up – include what the objects must consist of in order for this to occur.
17.) Explain how infrared waves and the Greenhouse Effect are related. Include the primary positive and negative aspects of the Greenhouse Effect.
18.) Match the following scientist with the portion of the electromagnetic spectrum that they discovered.
a) ultraviolet Johann Ritter
b) infrared Wilhelm Roentgen
c) x-ray William Herschel
19.) X-ray photos show a ___________________ of an object because ________________ dense materials absorb or reflect the x-rays.
Behaviors of Light
1.) A crown glass (n = 1.52) window has a thickness of 4.1mm. How long does it take the light to pass perpendicularly through the plate?
2.) A light ray in air (n = 1.000293) is incident on a water surface (n = 1.333) at 67 to the normal.
a) What is the angle of reflection?
b) What is the angle of refraction?
3.) What is the critical angle for light emerging from diamond (n = 2.419) into air?
4.) A person is sitting in a boat looking into the water. A fish is under water at a depth of 2.8 m. How close (horizontally) must the fish be from the boat before the person can see it?
5.) A light ray has an incidence angle of 32 with the normal at the boundary of benzene (n = 1.501) and air. What is the angle of refraction of the light ray as it leaves benzene into water below?
air
benzene
water
Electric Forces and Fields
1.) A proton is placed at rest in an electric field. If the proton gains a kinetic energy of 8E-15 J over a distance of 0.1m, then what is the magnitude of the electric field?
2.) An electron and proton both start from rest from the same point within a uniform electric field of 470.0 N/C. How far apart are they 1.00ms after they are released? Ignore the gravitational attraction between the electron and proton.
3.) Three charges are aligned along a line. The first charge is 4.6 C, the second charge is 4.0 C, and the third charge is 11.3 C. Determine the equilibrium location of the second charge if the first and third charge are 0.8m apart.
4.) Three charges exist as shown below. The first charge is –17.4C, the second charge is –5.7 C, and the third charge is 3.9 C. Determine the direction and magnitude of the net electrostatic force on the second charge.
q1
4.3 m
61 53
q2 q3
5.2 m
5.) A charged body has a mass of 5.2 E-7 kg and an initial kinetic energy of 4.2 E-6 J. If it is placed in an electric field of 220 N/C, then how long will it take to bring a 5C charged body to rest?
Buouyancy
1.) State Archimedes Principle.
2.) A 20 kg canoe has a volume of 0.94 kg/m3. An average canoeist has a mass of 70 kg. If air is neglected and the density of water is 1000 kg/m3, then how many canoeists can the canoe hold before it submerges?
3.) A cylindrical ice float has a radius of 4 m, a thickness of 0.85 m, and a density of 934 kg/m3. What percentage of the ice float will submerge if 2 polar bears are on the ice with masses of 200 and 100 kg? Assume that the ice float is in ocean water that has a density of 1028 kg/m3.
Relativity
1.) A person on a spaceship is travelling 90% of the speed of light away from a planet. If 20 days pass by for someone on the spaceship, then how many days passed by for someone on the planet?
2.) An object that has a proper length of 15 m but is observed to have a length of 12m, then how fast must have it been travelling relative to the observer?
3.) A carbon atom (m = 2.0E-26 kg) travels with a speed of 0.75c. Calculate the:
a. rest energy
b. kinetic energy
c. total energy
4.) A person on the surface of a supermassive planet (m = 5.4E28kg) experiences 60s. The person’s friend is on an orbiting spaceship that follows a radius of 8.4E8 m. How many days does the person on the spaceship experience?
5.) If a bowling ball has a diameter of 24 cm, then what would its mass have to be in order for it to become a black hole?