Physics Exam #1

(Chapter 1) Select all values of x that make x^3-4x=0 true.

-2, 2, 0.

Convert 45g to kg.

.045kg (1kg = 1000g).

Convert .12m^2 to cm^2. (1m = 100cm).

1200m^2. (1m^2 = 10,000cm^2).

If the acceleration is constant, then the acceleration multiplied by the time interval gives the change in ________.

Velocity; you dumb?

Select the following that are not SI units. a) Fahrenheit. b) Kilograms. c) Meters. d) Seconds. e) Years. f) Kelvin. g) Hours.

a) Fahrenheit. e) Years. g) Hours.

(Chapter 2) Alice and Bob both want to describe the route of a bus, but Alice will use City Hall as her choice of origin (reference point) while Bob will use the Civic Center as his origin. Which of the following vectors will they describe as being the same for the bus? a) Position. b) Displacement. c) Distance.

b) Displacement. (Distance is not a vector).

What do more significant figures imply about a measurement? a) Increased accuracy. b) Increased precision. c) Increased confidence.

b) Increased precision.

Why is it important to graph data in a plot? a) It is easier to read the values of the data. b) It is easier to see patterns in a graph. c) It is more precise than a table of data.

b) It is easier to see patterns in a graph.

Which of the following elements is necessary to draw a motion diagram? a) Positions of the object at equally spaced positions. b) Positions of the object at equally spaced times. c) Horizontal and vertical axes that are perpendicular to each other.

b) Positions of the object at equal spaced times.

Select all of the following statements regarding motion diagrams and graphs that are true. a) A motion diagram is just another name for a graph of position versus time. b) A graph of position versus time can be used to created a motion diagram. c) A motion diagram can be used to create a graph of position versus time.

b, c.

During a traffic jam, motorized vehicles are close together and not moving. In one instance, a traffic jam is one lane wide and 1 kilometer long, and the distance between adjacent vehicles is about the same as the length of one vehicle. Approximately how many motorized vehicles are in this traffic jam? a) 1000. b) 1. c) 10. d) 100. e) 10000.

d) 100. (1 kilometer = 1000 meters).

What do speedometers indicate? a) Average speed. b) Instantaneous velocity. c) Average velocity. d) Instantaneous speed.

d) Instantaneous speed.

What are the possible values of a vector component? a) Positive or zero only. b) Positive only. c) Positive or negative only. d) Positive, negative, or zero.

d) Positive, negative, or zero.

An apple falls from a tree through the Earth's atmosphere. Is the apple in free-fall? a) Yes, if the gravitational pull of the Earth is negligibly small. b) Yes, if the apple is falling at constant velocity. c) No, because the apple is moving. d) No, because the apple is accelerating. e) Yes, if air resistance is negligibly small.

e) Yes, if air resistance is negligibly small.

For projectile motion, how is the angle of elevation defined? a) Angle of acceleration above the horizontal. b) Angle of the initial velocity below the horizontal. c) Angle of the final velocity below the horizontal. d) Angle of the final velocity above the horizontal. e) Angle of acceleration below the horizontal. f) Angle of the initial velocity above the horizontal.

f) Angle of the initial velocity above the horizontal.

Approximately how many plump, juicy blueberries would fit in a 2 L soda pop bottle? Consider the volume of one plump juicy blueberry to be approximately 1 cm3.

2,000.

The trajectory of projectile motion is ______. a) Parabolic. b) Hyperbolic. c) Linear. d) Exponential.

a) Parabolic.

True or false: An object in free-fall never moves upward.

False.

The rate P at which a star emits energy as electromagnetic waves is proportional to the fourth power of its absolute temperature T. Suppose a star's absolute temperature increases by 10.0%. Which of the following expressions represents the fractional increase in the rate P? a) (1+.10)^4-1 b) (.10)^4 c) (1+.10)-1 d) (1+.10)^4

a) (1+.10)^4-1

An object is initially moving at 5 m/s in the positive x-direction and after 5 seconds is moving at 5 m/s in the negative x-direction. What was the average acceleration of the object during the 5 s time interval? a) 0m/s^2 b) 2m/s^2 c) -2m/s^2

a) 0m/s^2. Reason: Average acceleration is equal to the change in velocity divided by the time interval.

An object traveling along the x-axis has a velocity of 2.0 m/s from 0 to 4.0 s, 0 m/s from 4.0 to 6.0 s, -2.0 m/s from 6.0 to 8.0 s, and 4.0 m/s from 8.0 to 10 s. What is the average velocity of the object from 0 to 10 s? a) 1.2m/s. b) 2m/s. c) 4m/s. d) 1m/s.

a) 1.2m/s. Reason: To find the average velocity, determine the displacement for each time interval by multiplying each velocity by the length of time traveled at that velocity, add the displacements, and then divide by the total time (10 s).

Upon what does the average acceleration depend? a) It depends on both the change in velocity and time interval. b) It only depends on the change in velocity. c) It only depends on the time interval.

a) It depends on both the change in velocity and time interval.

What things does Physics seek to describe on the most basic level? a) Matter and energy. b) The locations of specific constellations and stars. c) Mathematical relations. d) Space and time.

a) Matter and energy. d) Space and time.

Alice and Bob both want to describe the route of a bus, but Alice will use City Hall as her choice of origin (reference point) while Bob will use the Civic Center as his origin. Which of the following vectors will they describe differently for the bus? a) Position. b) Distance. c) Displacement.

a) Position.

During each time interval on a motion diagram, the magnitudes of the displacements are constant. If the object is moving in the positive x-direction, then what is the acceleration? a) Zero. b) In the negative x-direction. c) In the positive x-direction.

a) Zero.

Name value of each of the following in terms of (10)^x. a) cm. b) km. c) mm. d)m.

a) cm = 10^-2 meters. b) km = 10^3 meters. c) mm = 10^-3 meters. d) m = 10^1 meters.

Select all of the following that could be the magnitude of a vector. a) 2m. b) 8m/s^2. c) 5m/s. d) 0m. e) -4m/s^2. f) -7m.

a, b, c, d. Reason: Magnitudes are never negative.

Select all of the following that describe projectile motion. a) The acceleration of the object is along the vertical axis. b) The motion is influenced only by gravity. c) The motion is along one straight line. d) The object accelerates both horizontally and vertically.

a, b.

The acceleration of an object moving along a straight line is constant. Select all of the possible shapes for the graph of its position versus time. a) Straight line passing through the origin. b) Semicircle not passing through the origin. c) Parabola opening downward. d) Parabola opening upward. e) Semicircle passing through the origin. f) Straight line not passing through the origin.

a, c, d, f.

Select all the cases for which equation Δvx = ax Δt is valid. a) If the velocity changes linearly. b) If the acceleration is given for a specific moment even though it is changing. c) If we know the average acceleration. d) If the acceleration is constant.

a, c, d.

What are some of the reasons for plotting a graph of data? a) It makes it easier to see how one variable is related to another. b) It gives a more precise value for the data. c) It makes patterns more apparent.

a, c.

An object traveling in the positive x-direction has an acceleration of 2.0 m/s^2 from 0 to 4.0 s, 0 m/s^2 from 4.0 to 6.0 s, -2.0 m/s^2 from 6.0 to 8.0 s, and 0 m/s^2 from 8.0 to 10 s. What is the average acceleration of the object from 0 to 10 s? a) 1.2m/s^2. b) 0.4m/s^2. c) 0m/s^2.

b) 0.4m/s^2.

How many pieces of information are needed to specify the position of an object? a) 4. b) 3. c) 2. d) 1.

b) 3.

A car starts from rest and moves with constant acceleration during a certain time interval Δt. Its final speed is 20 m/s. What would be its final speed if it started from rest and moved with the same constant acceleration during twice the time interval 2Δt? a) 20m/s. b) 40m/s. c) 10m/s. d) 14m/s.

b) 40m/s.

Physics seeks to ______. a) Come up with an separate equation for each and every phenomena. b) Describe the universe at the most fundamental level. c) Classify as many phenomena as possible in distinct categories.

b) Describe the universe at the most fundamental level.

A car travels around a circular track counterclockwise (as viewed from above). When the car is located at the east end of the circle, what is the direction of its velocity? a) North. b) South. c) West. d) East.

b) South. Reason: The car travels from the south end of the circle to the east end to the north end, in that order.

When is the maximum height of an ideal projectile equal to its initial vertical position? a) when the projectile is launched upward as some angle with respect to the horizontal. b) When the projectile is launched downward as some angle with respect to the horizontal. c) When the projectile is launched vertically upward.

b) When the projectile is launched downward as some angle with respect to the horizontal.

The acceleration of an object moving along a straight line is constant. Select all of the possible shapes for the graph of its velocity versus time. a) Parabola opening upward. b) Straight line passing through the origin. c) Horizontal line. d) Semicircle not passing through the origin. e) Semicircle passing through the origin. f) Parabola opening downward. g) Straight line not passing through the origin.

b, c, g.

Select all of the following that correctly identify what a factor is. a) It is a conversion from one unit system to another. b) It is a ratio. c) It is a number by which a quantity is multiplied or divided.

b, c.

The motion diagram for an object moving along a straight line consists of dots that are equally spaced, that is, the distance between adjacent dots is constant. Select all of the position versus time graphs below that could possibly correspond to this motion diagram. Position is plotted on the vertical axis, and time is plotted on the horizontal axis. a) A horizontal line that doe snot pass through the origin. b) A straight line with a slope of 10m/s that does not pass through the origin. c) A straight line with a slope of 10m/s that passes through the origin.

b, c.

Select all of the following which are required to determine instantaneous acceleration. a) The change in velocity during a very long time interval. b) A very short time interval. c) A very long time interval. d) The change in velocity during a very short time interval.

b, d.

The sum of two vectors is equal to the zero vector. Select all statements that are true. a) The two vectors point in the same direction. b) The two vectors have the same magnitude. c) The two vectors are perpendicular. d) The two vectors have different magnitudes. e) The two vectors point in opposite directions.

b, e.

For the following statement, match the letter of the missing word in the left column with the missing word in the right column. A motion diagram for projectile motion should show the horizontal velocity components to be WORD A, and the vertical velocity components to be WORD B. Word A (horizontal) Constant Word B (vertical) Changing

bro that is right

Match each acceleration on the right with resulting motion on the left. Change direction Acceleration points in the --y direction and velocity points in the + x direction. Increase speed Acceleration points in --y direction and velocity points in --y direction. Decrease speed Acceleration points in --y direction and velocity points in + y direction.

bro that is right

Match the quantities on the left with equivalent quantities on the right. 360cm 3.60m 360mm 0.360m 360m/min 6m/sec 360m/hour .1m/sec

bro that is right

Match the quantity on the left with the graphical interpretation on the right. Instantaneous velocity The slope of the tangent line at a point on a graph of position versus time. Average velocity The slope of the chord connecting two points on a graph of position versus time.

bro that is right

Match the set of three metric prefixes on the left with their relative numerical relationship on the right. Pay careful attention to the ratios. k, c, m 10^6:10:1 c, m, μ 10^4:10^3:1 m, μ, p 10^9:10^6:1

bro that is right

Alice goes for a jog around a square park. She jogs 1.0 km north, 1.0 km east, 1.0 km south, and finally 1.0 km west, to end up back were she started 15 minutes later. What was the magnitude of her average velocity? a) 16km/hr. b) 0.27km/hr. c) 0km/hr. d) 4km/hr.

c) 0km/hr.

The displacement is (40 m, 30 degrees north of east), and the time interval is 20 s. The +x-axis points to the east, and the +y-axis points to the north. What is the y-component of the average velocity? a) 1.73m/s b) 2.00m/s c) 1.00m/s

c) 1.00m/s. Reason: Average velocity is equal to displacement divided by time interval. Its y-component is equal to 1.00 m/s.

Alice goes for a jog around a square park. She jogs 1.0 km north, 1.0 km east, 1.0 km south, and finally 1.0 km west, to end up back were she started 15 minutes later. What was her average speed? a) 0.27km/hr b) 4.0km/hr c) 16km/hr d) 0km/hr

c) 16km/hr.

During each time interval on a motion diagram, the magnitude of the displacements are increasing. If the object is moving in the positive x-direction, then what is the acceleration? a) In the negative x-direction. b) Zero. c) In the positive x-direction.

c) In the positive x-direction.

Without an adjective, what does the word acceleration mean? a) Both instantaneous acceleration and average acceleration. b) Average acceleration. c) Instantaneous acceleration. d) Neither instantaneous acceleration and average acceleration.

c) Instantaneous acceleration.

An object is in free-fall. What are the object's velocity and acceleration when it is located at its highest point? a) Its acceleration is zero, but its velocity is not zero. b) Both its velocity and acceleration are not zero. c) Its velocity is zero, but its acceleration is not zero. e) Both its velocity and acceleration are zero.

c) Its velocity is zero, but its acceleration is not zero. Reason: Since the object is in free-fall, its acceleration is never zero. Since the object is located at its highest point, its velocity is zero.

To determine the instantaneous acceleration, what time interval must be used? a) Zero seconds. b) It must be shorter than any time interval that can be measured by the most accurate clock. c) The acceleration must be approximately constant during the time interval. d) One second.

c) The acceleration must be approximately constant during the time interval.

(Chapter 3) Select all of the following that occur to a vector when it is multiplied by the scalar negative one. a) Its direction stays the same. b) Its magnitude is multiplied by negative one. c) Its direction is multiplied by negative one. d) Its magnitude stays the same.

c, d.

Select all of the following that are always properties of a vector. a) Distance traveled. b) Length. c) Direction. d) Magnitude.

c, d.