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Physics Concepts and Connections. Self-tests 1. INSTRUCTOR: TAO LIN SHANDONG UNIVERSITY , WEIHAI Autumn 2011. Equations you will be provided. AU = Astronomical Unit ly = light year 10 -3 = milli (m) 10 -2 = centi (c) 10 3 = kilo (k) 10 6 = mega (M)
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Physics Concepts and Connections Self-tests 1 INSTRUCTOR: TAO LIN SHANDONG UNIVERSITY , WEIHAI Autumn 2011
Equations you will be provided AU = Astronomical Unit ly = light year 10-3 = milli (m) 10-2 = centi (c) 103 = kilo (k) 106 = mega (M) alpha (α), beta (β), gamma (γ), delta (δ), ... vavg = Δx/Δt aavg = Δv/Δt acent = v2/r v = vi+at x = xi + vit + ½at2 F = ma Weight = mg g=9.8 m/s2 (on Earth) F = GMm/r2 G = 6.67x10-11 N m2/kg2 p = mv F = Δp/Δt Work = Fd KE = ½mv2 Gravitational PE = mgh
Physics Concepts and Connections Self-tests 1-1 Universal scales
Which of the following lists objects correctly in order of increasing size? A. Earth, Galaxy, Solar system, Local group, Supercluster B. Local group, Earth, Solar system, Galaxy, Supercluster C. Earth, Galaxy, Solar system, Supercluster, Local group D. Earth, Solar System, Galaxy, Local Group, Supercluster
What is an AU? A. The average size of the Solar system B. The average distance from Earth to the nearest planet C. The average distance from Earth to the Sun D. The average diameter of the Galaxy
What is a light year? A. The time it takes light to travel to the nearest star B. The distance light travels in a year C. The time it takes light to travel across the galaxy D. The average diameter of the galaxy
How would we put 10,100,000,000 in scientific notation? A. 10 billion, one hundred million B. 1.01x101 C. 1.01x1010 D. 1.01x10-10
What is the largest structures in the universe? A. Superclusters B. Groups of several dozen galaxies C. Groups of millions of stars D. Links of Superclusters
The size of stars in a photograph represents their distance from us. A. True B. False
Physics Concepts and Connections Self-tests 1-2 Constellations, magnitudes, celestial sphere, seasons, moon phases, eclipses
Which star is brightest? A. Alpha Tauri (aka Aldebaran) B. Alpha Telescopium C. Gamma Orionis (aka Bellatrix) D. Beta Sagitarii (aka Arkab Prior)
The smaller the magnitude number,the dimmer the star. A. True B. False
The distance from the Earth to the sun changes. Seasons are a natural consequence of this fact. A. True B. False
What are the reasons for seasons? A. The distance from Earth to Sun changes B. The Earth is tilted C. The Earth orbits the Sun D. B and C E. All of these
If the moon is rising during sunset, what phase is it in? A. Full moon B. Waxing gibbous C. 1st quarter D. 3rd quarter E. None of these
When viewing a partial lunar eclipse, the moon is in the A. Umbra B. Penumbra C. Antumbra
Solar eclipses occur at new moon, but not every new moon. A. True B. False
Lunar eclipses occur at full moon, but not every full moon. A. True B. False
Physics Concepts and Connections Self-tests 1-3 Speed, velocity, acceleration, simple types of motion
A yacht is 20 m long. Express this length in feet. Use 1 m = 3.281 ft A. 6.096 ft B. 60.00 ft C. 65.62 ft D. 215.3 ft
A mechanical stopwatch uses a balance wheel that rotates back and forth 10 times in 2 seconds. What is the frequency of the balance wheel? A. 2 Hz B. 5 Hz C. 10 Hz D. 20 Hz
When lightning strikes, you see the flash almost immediately but the thunder typically lags behind. That is because the speed of light is so large (3 × 108 m/s) that it takes almost no time for the light to reach you.If the speed of sound is about 345 m/s, and the lightning flash is 1.6 km (1 mile) away, how long does it take the sound to reach you? A. 2.2 s B. 4.6 s C. 15.6 s D. 21.5 s
You are driving 65 mph down the freeway. A bus passes you, traveling 75 mph. You spot a passenger walking toward the front of the bus at a speed of 5 mph. How fast is the passenger traveling relative to you? A. 5 mph B. 10 mph C. 15 mph D. 20 mph
Your walking speed is 5 mph. If you hop on a conveyor belt, walking in the same direction that it’s moving, you travel 20 mph relative to the ground. You then turn around. How fast would you have to run to appear to be stationary relative to the ground? A. 5 mph B. 15 mph C. 20 mph D. 25 mph
A car travels 100 m in 5 seconds. What is its average speed? A. 100 m/s B. 50 m/s C. 20 m/s D. 10 m/s
My car can go from 0 to 60 mph in 8.3 seconds. What is its acceleration? A. 498 mph/s B. 51.7 mph/s C. 7.2 mph/s D. 2.4 mph/s • When you work out the conversion, it is 3.23 m/s2, which is equivalent to 0.33 g’s
Let’s estimate the acceleration of a car as it goes around a curve. The radius of a segment of a typical cloverleaf is 20 meters, and a car might take the curve with a constant speed of 10 m/s. A. 10 m/s2 B. 40 m/s2 C. 5 m/s2 D. 2 m/s2
Centripetal acceleration is an example of constant acceleration. A. True B. False • Why? • An object traveling in a circle will have its centripetal acceleration directed towards the center of the circle. If we represent this using an arrow, does the direction of the arrow change as the object moves?
What does the distance versus time graph look like for constant acceleration? A. Zero B. Flat C. Linear (constantly increasing) D. Curved E. None of these
Physics Concepts and Connections Self-tests 1-4 Forces, Mass, Newton’s laws, types of motion, gravitation
You need to move a heavy appliance that has no wheels. You apply as much force as possible, but it does not budge. What type of friction is preventing you from moving it? A. Static B. Kinetic C. Both
What type of friction is responsible for bringing a car to a screeching halt? A. Static B. Kinetic C. Both
If an object is not accelerating, what can you say about the forces acting on it? A. There are no forces acting on it. B. There are no frictional forces acting on it. C. It must have a constant force acting on it to keep it moving. D. It could have forces acting on it.
Two objects are moving at a constant velocity and you wish to stop them. Object A is twice as massive as object B. Which one is easier to stop? A. Object A B. Object B C. Since they are traveling at the same velocity, it will be equally easy to stop each object.
An automobile manufacturer decides to build a car that can accelerate uniformly from 0 to 60 mph (27 m/s) in 10 s. The car’s mass is to be about 1,000 kilograms. What is the force required? • A. 60,000 N • B. 27,000 N • C. 2700 N • D. 600 N
Last time, we computed the centripetal acceleration of a car going 10 m/s around a curve with a radius of 20 meters. If the car’s mass is 1,000 kilograms, what is the centripetal force that acts on it? • A. 5,000 N • B. 10,000 N • C. 20,000 N • D. 200,000 N
You toss a volleyball into the air. What is the acceleration of the volleyball when it is at its maximum height? A. Positive (upward) B. Negative (downward) C. Zero
You are peering over the edge of the roof when you loose your balance and fall. Luckily it has just snowed and there is a fresh blanket to break your fall. This allows you to contemplate Newton’s 3rd law on your way down. You reason that since the Earth is pulling on you, you should be pulling on the Earth. Is this true? A. Yes B. No
Describe Newton’s Three Laws Law 1 Law 2 Law 3
Two planets are orbiting each other. An alien civilization decides to use advanced technology to separate them by three times their original distance. What is the ratio of the new gravitational force to the old one? A. 9 B. 3 C. 1/3 D. 1/9
Physics Concepts and Connections Self-tests 1-5 Conservation laws, momentum, kinetic and potential energy, work, collisions
Which of the following objects have momenta equal to 1 kg m/s? A. 5 gm bullet traveling at 200 m/s B. 60 gm tennis ball traveling at 16.7 m/s C. 1 kg ball traveling at 1 m/s D. 100 kg man walking 1 cm/s E. All of these
A car (mass 2000 kg) traveling at 100 mph collides with a smaller car (820 kg) and hooks together. What is their final speed? A. 100 mph B. 35.5 mph C. 8.2 mph D. 0 mph
Because of friction, a constant force of 100 N is needed to slide a box across a room. If the box moves 3 meters, how much must be done? A. 300 J B. 33.3 J C. 100 J D. 3 J E. 980 J
In sliding a box across the floor, you exert 100 N of force. Is the work done by friction positive or negative? A. Positive B. Negative C. Unable to determine
Fred lifts a 30 kg barrel to a height of 1.2 m. How much work does he do? A. 36 J B. 353 J C. 4,000 J D. Unable to determine.
A ball (A) is moving with a certain speed. A second ball (B) is moving at twice the speed, but is half as massive. How do their kinetic energies compare? A. KEA = KEB B. KEA = ½ KEB C. KEA = 2KEB D. We need their actual speeds and masses to determine this relationship.
In a particular situation the potential energy is defined to be zero at ground level. What is it in the hole? A. Positive B. Negative C. Zero also D. Undefined
I toss a 0.06-kg tennis ball straight up. When it leaves my hand, it has a speed of 20 m/s. Find how high the ball rises.
A car makes a perfectly inelastic collision with another car. Is momentum conserved? A. Yes B. No, inelastic collisions do not conserve momentum.