Final Exam Review Key PAP

2015

Momentum and CollisionVariable Unit

p, momentum kg*m/s

m, mass kg

v, velocity m/s

Δp, change in momentum kg*m/s or N*s

F, force N

Δt, change in time s

RotationVariable Unit

Θ, angular displacement rad

x, arc length m

r, distance or radius m

Vt, tangential velocity m/s

ω, angular speed rad/s

at, tangential acceleration m/s2

α, angular acceleration rad/s2

Δt, time s

ac, centripetal acceleration m/s2

Fc, centripetal force N

m, mass kg

G, gravitational constant 6.673x10-11

Rotation cont.Variable Unit

τ, torque Nm

F, force N

d, lever arm distance m

K, Kinetic Energy J

I, moment of inertia kgm2

ω, angular speed rad/s

SHMVariable Unit

v, velocity of wave m/s

f, frequency Hz

λ, wavelength m

T, period s

m, mass kg

k, spring constant N/m

l, length of pendulum m

g, acceleration due to gravity m/s2

Δx, distance compressed or stretched m

Sound and Waves Variable Unit

v, velocity of wave m/s

f, frequency Hz

λ, wavelength m

ElectrostaticsVariable Unit

F, force N

kc, Coulombs constant 8.99x109

q, charge C

r, distance between charges m

E, electric field strength N/C

CircuitsVariable Unit

I, current A

Q, charge C

t, time s

R, resistance Ω

V, voltage, potential difference V

#1

A. 360°

#2

C. 57.3°

#3

• C. 0.018rad/s2

#4

A. 3.4 rad/s2

#5• A. 39.0 rad/s

#6

• C. 0.3 m/s2

#7

• C. 6.7x10-3N

#8• B. An angular accelerationTorque is the analogue of force- it causes rotational acceleration on a mass.

#9

• D. Torque • τ=Fd

d

#10

• Torque is force applied times how far from the

force is from the center of rotation, τ=Fd a bigger d gives more τ.

• So, answer A is correct.

#11

• B, 240Nm

• τ= Fd= (300N)(0.8m)=240Nm

#12

• C, as far from hinges as possible.

#13

• C, 30cm

• τ= Fd• 40Nm=(133N)(d)• d= 40Nm/133N=0.3m=30cm

#14

• A, Mass and C, Velocity

• p=m*Δv

• Impulse = F*Δt = Δp, which is change in momentum

#15

•A, perfectly inelastic

• You can tell a perfectly inelastic collision because the objects in the collision "stick" together

• m1v1i + m2v2i = (m1 + m2)vf

#16

• C, elastic

• An elastic collision is an encounter between two bodies in which the total kinetic energy of the two bodies after the encounter is equal to their total kinetic energy before the encounter.

#17

• C, 4

• p=m*Δv• p=2m*2Δv• p=4m*Δv

#18

• C, The small car and the truck experience the same average force.

• Newton’s Thrid Law: For every act there is a reaction.

• Force of car on truck, Force of truck on car.

#19• B, 0.719 kg m/s toward the right∙

• pT=m1v1 + m2v2

• pT=(.450 kg)(0.850 m/s) + (.300 kg)(1.12 m/s)

• pT=0.3825 kgm/s + 0.336 kgm/s

• pT=0.7185 kgm/s

• Toward the right because the greater of the two numbers is positive

#20

• C, 4.4 kgm/s• Δp=m(vf-vi)• Δp=0.10(-19-25)• Δp= -4.4 kgm/s

#21

• B, they are inversely related

• Τ=1/f or f=1/Τ

#22

• C. 40Hz

• v=fλ• 20m/s=f(0.5m)• (20m/s)/(0.5m)=f

#23

• C. 330m/s

• v=fλ• V=(410Hz)(0.8m)

#24

• (a) 0.10 m• (b) 0.20 m• (c) v=f λ• v=(120)(0.20)• V=24m/s

(a)

(b)

#25

• A. All harmonics are present

#26

• C. Only odd harmonics are present

#27

• C. 82

• Beat frequency formula: F=Bf-Bi• F=522 Hz -440 Hz• F=82 Hz

#28

• B. Higher than the original pitch and increasing as he falls

• The Doppler effect; pitch gets higher the object gets closer.

#29

• C. Are longitudinal waves

• Not part of EM spectrum- that is light…• Needs solid, liquid, gas (no sound in space)

#30• C. Rise, then drop• Rises as it approaches (less spaced out as waves

catch up a little as car makes them).

• Drops as it goesaway- spaces out as it leaves sound behind.

#31

• B. Conductors

• The charge on an insulatorwon’t move, so you can’t induce a charge as shown tothe right.

#32

• A. Charges on their surface do not move.

• Insulators aren’t good at conducting charge or heat. (air, fabrics, rubber, etc.)

• Conductors feel cold at room temperature because they conduct the heat from your hand easily (even though they are room temperature).

#33

• B. Induction

#34

• A. 320N

• You must change cm to m (0.15m)• μ is 10-6

• F=(8.99x109)(2x10-6)(-4x10-6)/(0.152)

#35

• A. 91N

• 2e means you have 2 electrons.• 79e means it has a charge of 79 electrons.

• F=(8.99x109)(2(-1.6x10-19))(79(-1.6x10-19)) / ((2x10-14)2)

#36

• B. There will be no net movement of charge.

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#37• E. C, A, B

• P=I*V • V is the same for every set up (says this in the question)• I=V/R• P=V2/R• Since every bulb is the same, they have the same R. So,

you have to look at how they are set up and how many.• A is series only one Rt=R• B is in series with two Rt=R1 + R2• C is in parellal with two Rt=(R1 + R2) -1

#38

• C. 6.0 V

• Rt=(R1+R2)-1=(4+12)-1= 3 Ω• V=IR = (2)(3) = 6.0 V

Voltage Current Resistance

1 4

2 12

Total 6 2 3

#39

• C. 2 C

• I=Q/Δt

• (0.1A)=Q/20s• (0.1A)(20s)=Q

#40

• B. 1.34A

• I=Q/Δt

• I=2.67C/2.00s

#41

• B. 25V

• V=IR (Ohm’s Law)

• V=(5.0A)(5.0Ω)

#42

• C. 0.50A

• V=IR (Ohm’s Law)

• 120V= (I)(240Ω) Solving for I….

• I= 120V/240Ω

#43

• A. 0.63A

• P=IV

• 75W=I(120V) Solving for I…

• I=75W/120V

#44

• C. 9.0Ω

• Since P=IV ……if we solve for V, then plug that V into V=IR we can solve for R

• P=IV 325W=(6A)V V=325W/6A=54.2V• V=IR 54.2V=(6A)R R=54.2V/6A=9.0Ω

#45

• A. 110V

• An easier way to do #55 would be to combine the P=IV and V=IR equations into one. Plug V/R in for I in the P=IV equation.

• P=V2/R 100W=V2/120Ω

• V=square root of ((100W)(120Ω))=110V

#46

• B. 1.3A

• Combine the P=IV and V=IR equations into one. This time, plug IR into V in the P=IV equation.

• P=I2R 80W=(I2)45Ω

• I= square root of (80/45)

#47

• A. 18Ω

• In a series, REQ= R1 + R2 + R3….

• REQ= 4 Ω + 6 Ω + 8 Ω

• REQ= 18 Ω

#48

• D. 1.9 Ω

• In a parallel circuit, the equivalent resistance is found by adding the inverses and inverting the total.

• REQ = (1/R1 + 1/R2 + 1/R3 +…..)-1

• REQ = (1/4 + 1/6 + 1/10)-1

#49

• D. REQ = (1/R1 + 1/R2 + 1/R3 +…..)-1

(Just like you did in #48)

Yay you!

#50

• C, -10

• Because the only force acting on it is Force of Gravity, which as an acceleration of about 10 m/s downward toward Earth.

• Just like all the other questions I have asked you over projectiles!