Physics Final Exam Practice

2.0702 m/s south

A 1250-kg car traveling 26m/s north collides with a 1600-kg SUV traveling 24m/s south. If they stick together, what is their final velocity?

17.921s

A Segway's maximum speed 5.58m/s. How long will it take you to ride 100m at maximum speed?

-8.333 cm away from the lens on the same side as the object. virtual not inverted minified

A diverging lens of focal length 50 cm is used to form an image of an object 10 cm away from the lens. Where is the image? Describe it.

radar gun: instantaneous speed following: average speed

A police officer on the side of the road aims his radar gun towards you as you pass. A different police officer has been following you, timing how long it takes you to travel that mile. Which officer measures average speed and which officer measures instantaneous speed?

radio waves

what is an example of an electromagnetic wave

5.0092 m

How high is a 550-kg wrecking ball raised if its potential energy is 27000J?

189000 J

How much heat is required to raise the temperature of 0.6kg of aluminum (c=900J/kg*K) from 100K to 450K?

8000 N

If a 2000-kg boat must accelerate at 4 m/s², what net force must be applied to the boat?

252 m/s

If a 60-kg person steps out of an airplane (so vi=0m/s) at 4000m above the ground, what will her speed be when she deploys her parachute at 760m above the ground? Use conservation of energy.

43.2 J

If a 60-kg person tangos across the ballroom at a speed of 1.2m/s, what is that person's kinetic energy?

0.54 W

If a 9V battery is connected to a 150Ω resistor, what is the power?

1454 ft

If a high speed particle is traveling horizontally over New York City at 0.5 c (so that γ = 1.154), how high with the Empire State Building look to the particle? (It looks 1454 ft to us on earth.)

0.3074694384 m

If a lead (α=29x10⁻⁶ 1/K) ruler is 0.3048m at 298K, how long is it at 600K?

electrons, 3

If a nitrogen ion has a net charge of -4.806x10⁻¹⁹C, does it have excess protons or excess electrons? How many?

0.1 Hz

If a pendulum goes from one side to the other in 5s, what is its frequency?

a

If a solid is changing to a liquid, are you a) adding heat b) removing heat c)increasing temperature, d) decreasing temperature

2.709 m/s²

If an elevator starts from rest and rises 40ft in 3s at a constant acceleration, what is that acceleration (in SI units)?

4 x 10⁻⁴ m

If an infrared wave has a frequency of 7.5 x 10¹¹ Hz, what is its wavelength?

625 Kg

If it takes 50N to push a car from rest 4m in 10s, what is the car's mass?

yes

If light is refracting from water (n = 1.33) to air (n=1), is total internal reflection possible?

solid

If the atoms in a substance stay in one location and do not move past each other, which phase is the substance in?

brighter

If two light waves experience constructive interference, will the resulting light be brighter or darker than the individual waves?

momentum

If you know the position of an electron of an atom precisely with no uncertainty, what can you not know at all about the electron?

59º

If you launch a projectile at an angle of 31º, what other launch angle will give you a range equal to your range?

14 N, no the forces do not cancel

If you push against the wall of a swimming pool with a force of 14N, what force does the wall of the swimming pool exert on you? Do the forces cancel?

curved

If you stand 3ft in front of a mirror and see your reflection 5ft behind the mirror, are you looking at a plane or curved mirror?

toward the center at a magnitude of 5.33 m/s²

If you stir a drink at a speed of 40cm/s, and the distance from the center of the drink to your straw is 3cm, what is the magnitude and direction of the centripetal acceleration?

Distance: 4878.032m Displacement: 4828.291m NE ish

If you walk 3mi north, then 50m east, what is your distance AND your displacement in SI units?

south

If your car is skidding north on a slippery road, what direction is the force of friction?

1.796 s

Imagine if the Millennium Falcon was traveling at 0.8c (so that γ = 1.67) when the first Death Star exploded. If the explosion took 3s according to Han on the Millennium Falcon, how long did it take according to the Death Star?

wave pulse

Is a pebble dropped in a pond an example of a wave pulse or a continuous wave?

none

What is the SI unit for: Index of Refraction

kilograms (Kg)

What is the SI unit for: Mass

Watts (W)

What is the SI unit for: Power

Passcal (Pa)

What is the SI unit for: Pressure

Kelvin (K)

What is the SI unit for: Temperature

meters per second (m/s)

What is the SI unit for: Velocity

volts (v)

What is the SI unit for: Voltage

meters (m)

What is the SI unit for: Wavelength

Newtons (N)

What is the SI unit for: Weight

none

What is the SI unit for: magnification

meters (m)

What is the SI unit for: wavelength

-3.6045 x 10⁻⁷ A (or C/s)

What is the current if 4500 electrons pass a point in a wire in 2ns?

-15769.6875 N

What is the force between a 0.07C charge and an electron 80nm apart?

1.695 x 10⁸ m/s

What is the the speed of light in a sapphire (n = 1.77)?

3.29774 N

What is the weight of a 5-kg gallon of paint on the surface of Pluto? Mpluto =1.31 x 10²² kg Rpluto =1.151 x 10⁶ m

39627.501 m³

What volume of ballast air is required to keep a 400,000,000N freighter afloat on seawater?

1.118 x 10⁻⁶ m

What wavelength of light is absorbed by a Si solar cell whose bandgap is 1.11eV

Kelvin

Which temperature scale measures 0 at absolute zero?

weight (mass does not change)

Which will be lower on the moon: your mass or your weight?

the sun is a blackbody and yellow is at the peak wavelength of the blackbody curve at the temperature of the sun

Why is the sun yellow?

My shirt absorbs all other wavelengths of color and reflects the wavelength of light that is red which makes my shirt appear red

Why is your shirt the color that it is?

137/55 Cs → 4/2 α + 133/53 I

Write the equation for alpha decay of ¹³⁷Cs.

25 m/s

You are playing ultimate frisbee in an artificial environment where no external forces act on the frisbee besides the force applied by humans playing the game. If you catch a frisbee at 25m/s, how fast was it thrown?

400 Pa

You are trying to break down a door by running into it with a force of 1000N. If the door is 2.5m², how much pressure are you applying to the door? (assume your body is the same area as the door)

south

Fill in the blank: The south pole of a magnet is attracted to earth's geographic ____ pole?

21000 Kg/m³

Chemists often use g/cm³ for density measurements. Convert 21 g/cm³ to SI units.

the second hand of a clock will travel around the face once every 60 seconds

Describe an example of a periodic phenomenon.

convection - boiling water radiation - sun heating earth conduction - hot pot on counter (direct contact)

Describe an example of each type of heat transfer.

virtual not inverted minified diverging

Describe the image formed by the following ray diagram. What kind of lens?

towards

Does the electric field point towards or away from an electron?

5, 9-10, 12, 15, 18-22, 25 (all curves and sudden changes)

During what period(s) of time is the object accelerating?

Light is composed of multiple wavelengths of color. Each wavelength responds differently to refraction, so they split into separate colors.

Explain why dispersion occurs.

116424000 Pa

The density of seawater increases the farther down you go, so that at Mariana's Trench, the density of seawater is about 1080kg/m³. How much pressure does a 7-kg fish experience in Mariana's Trench, which is 11km below the surface? (Use1080kg/m³, not 1030kg/m³.)

8.68 x 10⁻²¹ m

The electron microscope I use accelerates electrons through a voltage of 200 kV, which means the electrons have an energy of 3.201 x 10⁻¹⁴ J. what is the wavelength of these electrons?

false

True or False: A constant magnetic field can affect stationary charges.

False

True or false: Acceleration changes an object's velocity; therefore, it also must change the object's speed.

false

True or false: Because light is made of photons, it must not be a wave

True

True or false: sources of light also give off heat.

3 mph

Two toddler brothers decide to race at the airport, but the younger brother runs while also on the moving sidewalk while the older brother runs on the ground. If the younger brother runs at 5mph and the older brother runs at 8mph, how fast does the moving sidewalk have to travel for the younger brother to at least tie his older brother? (It's okay to answer in mph.)

a - wavelength b - 2 x amplitude c - 1/2 x wavelength d - amplitude

What do each of these represent?

reflection

What is it called when a wave hits a boundary and bounces back?

meters per second squared (m/s²)

What is the SI unit for: Acceleration