# Second Semester Final Exam Review

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Second Semester Final Exam Review

Forces Mean Mrs.Trunchbull whirls a girl (weight 325 N) by the pigtails. If the girl is going around with a velocity of 15 m/s and the radius of the circle is 1.05 m, a. What is her centripetal acceleration? b. What force is required to keep her whirling around like this?

Forces Mean Mrs.Trunchbull whirls a girl (weight 325 N) by the pigtails. If the girl is going around with a velocity of 15.0 m/s and the radius of the circle is 1.05 m, a. What is her centripetal acceleration? ac = v2/r = (15.0m/s)2/1.05m = 214 m/s2 b. What force is required to keep her whirling around like this? Fc = mac = (325N/9.80) x 214 = 7097 N = 7.10 x 103 N

Forces Herman pushes on the handle of a lawn mower with a force of 325 N at an angle of 32 degrees down. The lawn mower has a mass of 12 kg. The force of friction between the lawnmower and the ground is 222N. What will be the acceleration of the lawnmower?

Forces Herman pushes on the handle of a lawn mower with a force of 325 N at an angle of 32 degrees down. The lawn mower has a mass of 12 kg. The force of friction between the lawnmower and the ground is 222N. What will be the acceleration of the lawnmower? 4.5 m/s2

Energy Problems You throw an apple at a target. If the apple has a mass of 1.5 kg and you throw it with a velocity of 3.0 m/s. How much kinetic energy does the apple have?

Energy Problems You throw an apple at a target. If the apple has a mass of 1.5 kg and you throw it with a velocity of 3.0 m/s. How much kinetic energy does the apple have? 6.75 J

Energy Problems You throw the apple up in the air. It goes up from your hand (h=1.0 m) and reaches a height of 5.0 m. How much energy does this take? Remember, the apple has a mass of 1.5 kg.

Energy Problems You throw the apple up in the air. It goes up from your hand (h=1.0 m) and reaches a height of 5.0 m. How much energy does this take? Remember the apple has a mass of 1.5 kg. 59 J

Gravity Problems Astronauts in an orbiting space shuttle experience a sensation of weightlessness because . a. the space shuttle is not affected by the earth’s gravity b. the space shuttle is moving away from the earth c. the space shuttle is falling freely toward the earth d. the mass of the space shuttle decreases as the distance from the earth increases

Gravity Problems Astronauts in an orbiting space shuttle experience a sensation of weightlessness because . a. the space shuttle is not affected by the earth’s gravity b. the space shuttle is moving away from the earth c. the space shuttle is falling freely toward the earth d. the mass of the space shuttle decreases as the distance from the earth increases

Gravity Problems Two satellites of equal mass are put into orbit 31 m apart. The gravitational force between them is 2.0 x 10-7 N. What is the mass of each satellite?

Gravity Problems Two satellites of equal mass are put into orbit 31 m apart. The gravitational force between them is 2.0 x 10-7 N. What is the mass of each satellite? m= 1697 kg = 1700 kg (two sig figs)

Electrostatics Problems
You want to charge a ball using induction. You would: Rub the ball with silk, removing electrons and charging it Rub the ball with silk, removing protons and charging it Bring a charged object near it, causing the electrons to move.

Electrostatics Problems
4. You want to charge a ball using induction. You would: Rub the ball with silk, removing electrons and charging it Rub the ball with silk, removing protons and charging it Bring a charged object near it, causing the electrons to move.

Electrostatic Problems
A balloon with a charge of 7.6 x 10-6 C is sitting in an electric field with a strength of 4.5 x 10-5 N/C. How much force does the object feel?

Electrostatic Problems
A balloon with a charge of 7.6 x 10-6 C is sitting in an electric field with a strength of 4.5 x 10-5 N/C. How much force does the object feel? 3.4 x N

Electrostatic Problems
You are outside during an electrical storm. Where is the safest place to hide? Standing in a field with your umbrella Under a tree Standing in field without your umbrella In a metal mesh chicken coop.

Electrostatic Problems
You are outside during an electrical storm. Where is the safest place to hide? Standing in a field with your umbrella Under a tree Standing in field without your umbrella In a metal mesh chicken coop.

Electricity Problems You add resistors in parallel to a circuit. What happens to the overall resistance? It increases It decreases It stays the same Too little information to tell

Electricity Problems You add resistors in parallel to a circuit. What happens to the overall resistance? It increases It decreases It stays the same Too little information to tell

Electricity Problems You hook a 5.0 ohm resistor and 6.0 ohm resistor up in series to a 12 V battery. What is the current in this circuit?

Electricity Problems You hook a 5.0 ohm resistor and 6.0 ohm resistor up in series to a 12 V battery. What is the current in this circuit? 1.1 A

Electricity Problems You hook a 5.0 ohm resistor and 6.0 ohm resistor up in parallel to a 12 V battery. What is the total current in this circuit?

Electricity Problems You hook a 5.0 ohm resister and 6.0 ohm resister up in parallel to a 12 V battery. What is the total current in this circuit? 4.4 A

Prepared Basic A slinky will transmit a wave at a speed of 7.34 m/s. The distance from a crest to a trough in this wave is 0.31 m. What is the period of this wave? What is the period of a wave? What units are used to describe the period? What is the symbol for the period? What is a wavelength? What units are used to describe the wavelength? What is the symbol for the wavelength?

Prepared Basic A slinky will transmit a wave at a speed of 7.34 m/s. The distance from a crest to a trough in this wave is 0.31 m. What is the period of this wave? What is the period of a wave? What units are used to describe the period? What is the symbol for the period? What is a wavelength? What units are used to describe the wavelength? What is the symbol for the wavelength? Answer = s

Prepared Basic A sound wave is produced at room temperature. If the frequency of the wave is 153 Hz… Find the distance between compressions Draw the wave and label the important parts of the wave. What is responsible for the speed of a wave? Is this a mechanical wave? You have a lovely singing voice. What type of wave is this? Draw it. Label the important parts of the wave. How many waves are made every second? Is this a mechanical wave? 28

Prepared Basic You have a lovely singing voice.
A sound wave is produced at room temperature. If the frequency of the wave is 153 Hz… Find the distance between compressions Answer = 2.24 m Draw the wave and label the important parts of the wave. What is responsible for the speed of a wave? Answer = the density and elasticity of the medium Is this a mechanical wave? Answer = Yes! All sound waves are mechanical. You have a lovely singing voice. What type of wave is this? Draw it. Label the important parts of the wave. How many waves are made every second? Is this a mechanical wave? 29

Prepared Basic A 12 meter rope is used to create a standing wave with a wavelength of 3 m. Draw the standing wave. What harmonic frequency produced this wave form? Describe how nodes and antinodes are created. What is a transverse wave? Give an example. What is a longitudinal wave? Give and example. What is a standing wave? Draw a complete standing wave and label its wavelength, nodes and antinodes. 30

Prepared Basic A 12 meter rope is used to create a standing wave with a wavelength of 3 m. Draw the standing wave. What harmonic frequency produced this wave form? Answer = eighth harmonic Describe how nodes and antinodes are created. Answer = interference of identical waves moving in opposite directions What is a transverse wave? Give an example. What is a longitudinal wave? Give and example. What is a standing wave? Draw a complete standing wave and label its wavelength, nodes and antinodes. 31

Prepared Basic Someone whispers to you at 30 dB. You answer back at 70 dB. How much louder were you being? What unit do we commonly use to measure sound intensity? 32

Prepared Basic Someone whispers to you at 30 dB. You answer back at 70 dB. How much louder were you being? Answer = you were speaking with times more sound intensity (10x10x10x10); each 10 dB jump = 10x What unit do we commonly use to measure sound intensity? dB 33

Prepared Basic You take a yellow rose under a blue light. What color will the rose appear to be? A) yellow B) Red C) Green D) Black You take a yellow rose under a red light. What color will the rose appear to be? A) yellow B) Red C) Green D) Black 34

Prepared Basic You take a yellow rose under a blue light. What color will the rose appear to be? A) Yellow B) Red C) Green D) Black Answer = Black—a yellow rose can only reflect green and/or red, not blue You take a yellow rose under a red light. What color will the rose appear to be? A) yellow B) Red C) Green D) Black 35

Principle of Optical refraction
Snell’s Law: describes the angle of refracted light. ni,r = index of refraction (see table 17-1; p.397) ni sin Θi = nr sin Θr If ni < nr ; then goes into a more optically dense medium and bends towards the normal line. If ni > nr ; then bends away from the normal

Prepared Basic A radio wave is traveling through a city. It has a wavelength of 45 m. What is the frequency of this wave? How far will it travel it travel in 2 minutes? Draw a light wave. Label its parts and describe its properties. How far can light travel in 50 seconds? 38

Prepared Basic A radio wave is traveling through a city.
How far will it travel it travel in 2.0 minutes? Answer = 3.6 x 1010 m Draw a light wave. Label its parts and describe its properties. How far can light travel in 50.0 seconds? Answer = 1.50 x 1010 m 39 39

Question 1 How much power does an elevator exert lifting a 3423 kg elevator 10.0 meters in 12.0 seconds?

Question 1 How much power does an elevator exert lifting a 3423 kg elevator 10.0 meters in 12.0 seconds? mgh / t = P (3423 * 9.80 * 10.0) / 12.0 = W = 2.80x104 W

Question 2 Two astronauts floating in space together double the distance between them. What happens to the gravitation force between them?

Question 2 Two astronauts floating in space together double the distance between them. What happens to the gravitation force between them? It decreases to ¼ of what it was.

Question 3 I rub a balloon against my head. How am I charging up the balloon. Charging by friction, causing the electrons to move Charging by induction, causing the protons to move Charging by friction, causing the protons to move Charging by induction, causing the electrons to move

Question 3 I rub a balloon against my head. How am I charging up the balloon. Charging by friction, causing the electrons to move Charging by induction, causing the protons to move Charging by friction, causing the protons to move Charging by induction, causing the electrons to move

Question 4 True or false: Friction is necessary for you to drive your car.

Question 4 True or false: Friction is necessary for you to drive your car. Explain your answer. True! Without friction, we could not start or stop.

Question 7 As a roller coaster rides down a track, for a split second it has a kinetic energy of 1023 J and a potential energy of 786 J. What is the mechanical energy of the cart at this moment?

Question 7 As a roller coaster rides down a track, for a split second it has a kinetic energy of 1023 J and a potential energy of 786 J. What is the mechanical energy of the cart at this moment? = 1809 J

Question 8 What do the arrows in an electric field tell us?

Question 8 What do the arrows in an electric field tell us? The direction a small positive test charge would move.

Question 9 Which of the following would not change the frictional force of an object you are dragging. Changing the angle or your pulling force Changing the weight of the object Changing the area of contact without changing the mass of the dragged object Changing what the surfaces in contact are made of.

Question 9 Which of the following would not change the frictional force of an object you are dragging. Changing the angle or your pulling force Changing the weight of the object Changing the area of contact without changing the mass of the dragged object Changing what the surfaces in contact are made of.

Question 12 You are moving into your new dorm and carrying your bag up to your room. What would take less work from a physics perspective. Taking the steep back staircase Taking the front spiral staircase. Climbing a specially built ramp All of these would take the same amount of work.

Question 12 You are moving into your new dorm and carrying your bag up to your room. What would take less work from a physics perspective. Taking the steep back staircase Taking the front spiral staircase. Climbing a specially built ramp All of these would take the same amount of work.