Physics Midterm 1
A commemorative coin that sells for $40 is advertised to be plated with 15 mg of gold. Suppose gold is worth about $1,300 per ounce. Which of the following best represents the value of the gold in the coin? A. $0.33 B. $0.69 C. $3.30 D. $6.90
B. $0.69
If a car decelerates from 20 m/s to 15 m/s in 5 s, what is Delta v? A. -5 m/s B. -1 m/s C. 1 m/s D. 5 m/s
A. -5 m/s
The uncertainty of a triple-beam balance is 0.05 g. What is the percent uncertainty in a measurement of 0.445 kg? A. 0.011% B 0.11% C 1.1% D. 11%
A. 0.011%
A car weighs 2,000 kg. It moves along a road by applying a force on the road with a parallel component of 560 N. There are two passengers in the car, each weighing 55 kg. If the magnitude of the force of friction experienced by the car is 45 N, what is the acceleration of the car? A. 0.244 m/s^2 B. 0.265 m/s^2 C. 4.00 m/s^2 D. 4.10 m/s^2
A. 0.244 m/s^2
A plane flies north at 200 m/s with a headwind blowing from the north at 70 m/s. What is the resultant velocity of the plane?* A. 130 m/s north B. 130 m/s south C. 270 m/s north D. 270 m/s south
A. 130 m/s north
A person weighing 55 kg walks by applying 160 N of force on the ground, while pushing a 10-kg object. If the person accelerates at 2 m/s^2, what is the force of friction experienced by the system consisting of the person and the object? A. 30 N B. 50 N C. 270 N D. 290 N
A. 30 N
A person wants to fire a water balloon cannon such that it hits a target 100 m away. If the cannon can only be launched at 45° above the horizontal, what should be the initial speed at which it is launched? A. 31.3 m/s B. 37.2 m/s C. 980.0 m/s D. 1,385.9 m/s
A. 31.3 m/s
A large rock is ejected from a volcano with a speed of 30.0 m/s and at an angle 60° above the horizontal. The rock strikes the side of the volcano at an altitude of 10.0 m lower than its starting point. Calculate the horizontal displacement of the rock. A. 84.90 m B. 96.59 m C. 169.80 m D. 193.20 m
A. 84.90 m
Which of the following is used to represent an object in a free-body diagram? A. A point B. A line C. A vector
A. A point
How can we express the x and y-components of a vector in terms of its magnitude, A, and direction, global angle theta? A. A_x = A_cos theta; A_y = A_sin theta B. A_x = A_cos theta; A_y = A_cos theta C. A_x = A_sin theta; A_y = A_cos theta D. A_x = A_sin theta ; A_y = A_sin theta
A. A_x = A_cos theta; A_y = A_sin theta
Describe the difference between an observation and a hypothesis. A. An observation is seeing what happens; a hypothesis is a testable, educated guess. B. An observation is a hypothesis that has been confirmed. C. Hypotheses and observations are independent of each other. D. Hypotheses are conclusions based on some observations.
A. An observation is seeing what happens; a hypothesis is a testable, educated guess.
Horizontal and vertical motions of a projectile are independent of each other. What is meant by this?* A. Any object in projectile motion falls at the same rate as an object in freefall, regardless of its horizontal velocity. B. All objects in projectile motion fall at different rates, regardless of their initial horizontal velocities. C. Any object in projectile motion falls at the same rate as its initial vertical velocity, regardless of its initial horizontal velocity. D. All objects in projectile motion fall at different rates and the rate of fall of the object is independent of the initial velocity.
A. Any object in projectile motion falls at the same rate as an object in freefall, regardless of its horizontal velocity.
Alan starts from his home and walks 1.3 km east to the library. He walks an additional 0.68 km east to a music store. From there, he walks 1.1 km north to a friend's house and an additional 0.42 km north to a grocery store before he finally returns home along the same path. What is his final displacement and total distance traveled? A. Displacement is 0 km and distance is 7 km. B. Displacement is 0 km and distance is 3.5 km. C. Displacement is 7 km towards west and distance is 7 km. D. Displacement is 3.5 km towards east and distance is 3.5 km.
A. Displacement is 0 km and distance is 7 km.
In a coordinate system in which the direction to the right is positive, what are the distance and displacement of a person who walks 35 m to the left, 18 m to the right, and then 26 m to the left? A. Distance is 79 m and displacement is -43 m. B. Distance is -79 m and displacement is 43 m. C. Distance is 43 m and displacement is -79 m. D. Distance is -43 m and displacement is 79 m.
A. Distance is 79 m and displacement is -43 m.
What kind of force is friction? A. External force B. Internal force C. Net force
A. External Force
Rhianna and Logan start at the same point and walk due north. Rhianna walks with an average velocity (v_avg,R) Logan walks three times the distance in twice the time as Rhianna. Which of the following expresses Logan's average velocity in terms of v_avg,R? A. Logan's average velocity = 1.5 v_{avg,R}. B. Logan's average velocity = 2/3 v_{avg,R}. C. Logan's average velocity = 3 v_{avg,R}. D. Logan's average velocity = 1/2 v_{avg,R}.
A. Logan's average velocity = 1.5 v_{avg,R}.
s it possible to determine a car's instantaneous velocity from just the speedometer reading? A. No, it reflects speed but not the direction. B. No, it reflects the average speed of the car. C. Yes, it sometimes reflects instantaneous velocity of the car. D. Yes, it always reflects the instantaneous velocity of the car.
A. No, it reflects speed but not the direction.
Imagine that a car is traveling from your left to your right at a constant velocity. Which two actions could the driver take that may be represented as (a) a velocity vector and an acceleration vector both pointing to the right and then (b) changing so the velocity vector points to the right and the acceleration vector points to the left? A. (a) Push down on the accelerator and then (b) push down again on the accelerator a second time. B. (a) Push down on the accelerator and then (b) push down on the brakes. C. (a) Push down on the brakes and then (b) push down on the brakes a second time. D. (a) Push down on the brakes and then (b) push down on the accelerator.
B. (a) Push down on the accelerator and then (b) push down on the brakes.
Using the conventional choice for positive and negative axes described in the text, what is the y-component of the acceleration of an object experiencing projectile motion? A. -9.8 m/s B. -9.8 m/s^2 C. 9.8 m/s D. 9.8m/s^2
B. -9.8 m/s^2
An object has a mass of 1 kg on Earth. What is its weight on the moon?* A. 1 N B. 1.67 N C. 9.8 N D. 10 N
B. 1.67 N
If a marathon runner runs 9.5 mi in one direction, 8.89 mi in another direction and 2.333 mi in a third direction, how much distance did the runner run? Be sure to report your answer using the proper number of significant figures. A. 20 mi B. 20.7 mi C. 20.72 mi D. 20.732 mi
B. 20.7 mi
A ball is thrown in the air at an angle of 40°. If the maximum height it reaches is 10 m, what must be its initial speed?* A. 17.46 m/s B. 21.78 m/s C. 304.92 m/s D. 474.37 m/s
B. 21.78 m/s
he speed limit on some interstate highways is roughly 80 km/h. What is this in meters per second? How many miles per hour is this? A. 62 m/s, 27.8 mph B. 22.2 m/s, 49.7 mph C. 62 m/s, 2.78 mph D. 2.78 m/s, 62 mph
B. 22.2 m/s, 49.7 mph
How long does it take to accelerate from 8.0 m/s to 20.0 m/s at a rate of acceleration of 3.0 m/s^2? A. 0.25 s B. 4.0 s C. 9.33 s D. 36 s
B. 4.0 s
What would be the slope for a line passing through the two points below? Point 1: (1, 0.1) Point 2: (7, 26.8) A. 2.4 B. 4.5 C. 6.2 D. 6.8
B. 4.5
There is a vector A with magnitude 5 units pointing toward west, and a vector B with magnitude 3 units pointing toward south. Using vector addition, what is the magnitude of the resultant vector?* A. 4.0 B. 5.8 C. 6.3 D. 8.0
B. 5.8
Two people push a 2,000-kg car to get it started. An acceleration of at least 5.0 m/s^2 is required to start the car. Assuming both people apply the same magnitude force, how much force will each need to apply if friction between the car and the road is 300 N?* A. 4850 N B. 5150 N C. 97000 N D. 10300 N
B. 5150 N
You sit in a car that is moving at an average speed of 86.4 km/h. During the 3.3 s that you glance out the window, how far has the car traveled? A. 7.27 m B. 79 m C. 285 km D. 1026 m
B. 79 m
What does the area under a velocity vs. time graph line represent? A. acceleration B. displacement C. distance D. instantaneous velocity
B. Displacement
A car is moving on a straight road at a constant speed in a single direction. Which of the following statements is true? A. Average velocity is zero. B. The magnitude of average velocity is equal to the average speed. C. The magnitude of average velocity is greater than the average speed. D. The magnitude of average velocity is less than the average speed.
B. The magnitude of average velocity is equal to the average speed.
Three forces, A, B, and C, are acting on the same object with magnitudes a, b, and c, respectively. Force A acts to the right, force B acts to the left, and force C acts downward. What is a necessary condition for the object to move straight down?* A. The magnitude of force A must be greater than the magnitude of force B, so a > b. B. The magnitude of force A must be equal to the magnitude of force B, so a = b. C. The magnitude of force A must be greater than the magnitude of force C, so A > C. D. The magnitude of force C must be greater than the magnitude of forces A or B, so A < C > B.
B. The magnitude of force A must be equal to the magnitude of force B, so a = b.
A ball travels from north to south at 60 km/h. After being hit by a bat, it travels from west to east at 60 km/h. Is there a change in velocity?* A. Yes, because velocity is a scalar. B. Yes, because velocity is a vector. C. No, because velocity is a scalar. D. No, because velocity is a vector
B. Yes, because velocity is a vector.
Boat A and Boat B are traveling at a constant speed in opposite directions when they pass each other. If a person in each boat describes motion based on the boat's own reference frame, will the description by a person in Boat A of Boat B's motion be the same as the description by a person in Boat B of Boat A's motion? A. Yes, both persons will describe the same motion because motion is independent of the frame of reference. B. Yes, both persons will describe the same motion because they will perceive the other as moving in the backward direction. C. No, the motion described by each of them will be different because motion is a relative term. D. No, the motion described by each of them will be different because the motion perceived by each will be opposite to each other.
B. Yes, both persons will describe the same motion because they will perceive the other as moving in the backward direction.
Which of the following does not contribute to the uncertainty? A. the limitations of the measuring device B. the skill of the person making the measurement C. the regularities in the object being measured D. other factors that affect the outcome (depending on the situation)
C) the regularities in the object being measured
A position vs. time graph of a frog swimming across a pond has two distinct straight-line sections. The slope of the first section is 1 m/s. The slope of the second section is 0 m/s. If each section lasts 1 s, then what is the frog's total average velocity? A. 0 m/s B. 2 m/s C. 0.5 m/s D. 1 m/s
C. 0.5 m/s
The sides of a small rectangular box are measured 1.80 cm and 2.05 cm long and 3.1 cm high. Calculate its volume and uncertainty in cubic centimeters. Assume the measuring device is accurate to plus or minus 0.05 cm. A. 11.4 ± 0.1 cm^3 B. 11.4 ± 0.6 cm^3 C. 11.4 ± 0.8 cm^3 D. 11.4 ± 0.10 cm^3
C. 11.4 ± 0.8 cm^3
A motorcycle moving at a constant velocity suddenly accelerates at a rate of 4.0 m/s^2 to a speed of 35 m/s in 5.0 s. . What was the initial speed of the motorcycle? A. -34 m/s B. -15 m/s C. 15 m/s D. 34 m/s
C. 15 m/s
What is the global angle of 20° south of west?* A. 110° B. 160° C. 200° D. 290°
C. 200°
Two hikers take different routes to reach the same spot. The first one goes 255 m southeast, then turns and goes 82 m at 14° south of east. The second hiker goes 200 m south. How far and in which direction must the second hiker travel now, in order to reach the first hiker's location destination?* A. 200 m east B. 200 m south C. 260 m east D. 260 m south
C. 260 m east
The driver of a sports car traveling at 10.0 m/s steps down hard on the accelerator for 5.0 s and the velocity increases to 30.0 m/s. What was the average acceleration of the car during the 5.0 s time interval? A. -1.0 × 10^2 m/s^2 B. -4.0 m/s^2 C. 4.0 m/s^2 D. 1.0 × 10^2 m/s^2
C. 4.0 m/s^2
A bullet in a gun is accelerated from the firing chamber to the end of the barrel at an average rate of 6.30×10^5 m/s^2 for 8.10×10^−4 s. What is the bullet's final velocity when it leaves the barrel, commonly known as the muzzle velocity? A. 7.79 m/s B. 51.0 m/s C. 510 m/s D. 1020 m/s
C. 510 m/s
A bathroom scale shows your mass as 55 kg. What will it read on the moon? A. 9.4 kg B. 10.5 kg C. 55.0 kg D. 91.9 kg
C. 55.0 kg
What is the angle between the x and y components of a vector?* A. 0° B. 45° C. 90° D. 180°
C. 90°
Two people push a cart on a horizontal surface by applying forces F_1 and F_2 in the same direction. Is the magnitude of the net force acting on the cart, F_net, equal to, greater than, or less than F_1 + F_2? Why?* A. F_net < F_1 + F_2 because the net force will not include the frictional force. B. F_net = F_1 + F_2 because the net force will not include the frictional force C. F_net < F_1 + F_2 because the net force will include the component of frictional force D. F_net = F_1 + F_2 because the net force will include the frictional force
C. F_net < F_1 + F_2 because the net force will include the component of frictional force
Which of the following is a physical quantity that can be described by dynamics but not by kinematics? A. Velocity B. Acceleration C. Force
C. Force
Which of the following best describes the relationship between instantaneous velocity and instantaneous speed? A. Both instantaneous speed and instantaneous velocity are the same, even when there is a change in direction. B. Instantaneous speed and instantaneous velocity cannot be the same even if there is no change in direction of motion. C. Magnitude of instantaneous velocity is equal to instantaneous speed. D. Magnitude of instantaneous velocity is always greater than instantaneous speed.
C. Magnitude of instantaneous velocity is equal to instantaneous speed.
What is the net external force on an object in freefall on Earth if you were to neglect the effect of air?* A. The net force is zero. B. The net force is upward with magnitude mg. C. The net force is downward with magnitude mg. D. The net force is downward with magnitude 9.8 N.
C. The net force is downward with magnitude mg.
A person attempts to cross a river in a straight line by navigating a boat at 15 m/s. If the river flows at 5.0 m/s from his left to right, what would be the magnitude of the boat's resultant velocity? In what direction would the boat go, relative to the straight line across it? A. The resultant velocity of the boat will be 10.0 m/s. The boat will go toward his right at an angle of 26.6° to a line drawn across the river. B. The resultant velocity of the boat will be 10..0 m/s. The boat will go toward his left at an angle of 26.6° to a line drawn across the river. C. The resultant velocity of the boat will be 15.8 m/s. The boat will go toward his right at an angle of 18.4° to a line drawn across the river. D. The resultant velocity of the boat will be 15.8 m/s. The boat will go toward his left at an angle of 18.4° to a line drawn across the river.
C. The resultant velocity of the boat will be 15.8 m/s. The boat will go toward his right at an angle of 18.4° to a line drawn across the river.
How is the vector arrow representing an acceleration of magnitude 3 m/s^2 different from the vector arrow representing a negative acceleration of magnitude 3 m/s^2? A. They point in the same direction. B. They are perpendicular, forming a 90° angle between each other. C. They point in opposite directions. D. They are perpendicular, forming a 270° angle between each other.
C. They point in opposite directions.
A water balloon cannon is fired at 30 m/s at an angle of 50° above the horizontal. How far away will it fall?* A. 2.35 m B. 3.01 m C. 70.35 m D. 90.44 m
D. 90.44 m
he resultant vector of the addition of vectors a and vector b is vector r. The magnitudes of a, b, and r are A, B, and R, respectively. Which of the following is true? A. R_x + R_y = 0 B. A_x + A_y = vector A C. A_x + B_y = B_x + A_y D. A_x + B_x = R_x
D. A_x + B_x = R_x
Four bicyclists travel different distances and times along a straight path. Which cyclist traveled with the greatest average speed? A. Cyclist 1 travels 95 m in 27 s. B. Cyclist 2 travels 87 m in 22 s. C. Cyclist 3 travels 106 m in 26 s. D. Cyclist 4 travels 108 m in 24 s.
D. Cyclist 4 travels 108 m in 24 s.
Two identical items, object 1 and object 2, are dropped from the top of a 50-m building. Object 1 is dropped with an initial velocity of 0 m/s, while object 2 is thrown straight downward with an initial velocity of 13 m/s. What is the difference in time, in seconds rounded to the nearest tenth, between when the two objects hit the ground?* A. Object 1 will hit the ground 3.2 s after object 2. B. Object 1 will hit the ground 2.1 s after object 2. C. Object 1 will hit the ground at the same time as object 2. D. Object 1 will hit the ground 1.1 s after object 2.
D. Object 1 will hit the ground 1.1 s after object 2.
A body is pushed downward by a force of 5 units and upward by a force of 2 units. How would you draw a free-body diagram to represent this? A. Two force vectors acting at a point, both pointing up with lengths of 5 units and 2 units B. Two force vectors acting at a point, both pointing down with lengths of 5 units and 2 units C. Two force vectors acting at a point, one pointing up with a length of 5 units and the other pointing down with a length of 2 units D. Two force vectors acting at a point, one pointing down with a length of 5 units and the other pointing up with a length of 2 units
D. Two force vectors acting at a point, one pointing down with a length of 5 units and the other pointing up with a length of 2 units
For the motion of a falling object, which graphs are straight lines? A. Acceleration versus time only B. Displacement versus time only C. Displacement versus time and acceleration versus time D. Velocity versus time and acceleration versus time
D. Velocity versus time and acceleration versus time
In the definition of velocity, what physical quantity is changing over time? A. speed B. distance C. magnitude of displacement D. position vector
D. position vector
Passenger A sits inside a moving train and throws a ball vertically upward. How would the motion of the ball be described by a fellow train passenger B and an observer C who is standing on the platform outside the train? A. Passenger B sees that the ball has vertical, but no horizontal, motion. Observer C sees the ball has vertical as well as horizontal motion. B. Passenger B sees the ball has vertical as well as horizontal motion. Observer C sees the ball has the vertical, but no horizontal, motion. C. Passenger B sees the ball has horizontal but no vertical motion. Observer C sees the ball has vertical as well as horizontal motion. D. Passenger B sees the ball has vertical as well as horizontal motion. Observer C sees the ball has horizontalbut no vertical motion.
A. Passenger B sees that the ball has vertical, but no horizontal, motion. Observer C sees the ball has vertical as well as horizontal motion.
A 2,000-kg car is sitting at rest in a parking lot. A bike and rider with a total mass of 60 kg are traveling along a road at 10 km/h. Which system has more inertia? Why?* A. The car has more inertia, as its mass is greater than the mass of the bike. B. The bike has more inertia, as its mass is greater than the mass of the car. C. The car has more inertia, as its mass is less than the mass of the bike. D. The bike has more inertia, as its mass is less than the mass of the car.
A. The car has more inertia, as its mass is greater than the mass of the bike.
A test car carrying a crash test dummy accelerates from 0 to 30 m/s and then crashes into a brick wall. Describe the direction of the initial acceleration vector and compare the initial acceleration vector's magnitude with respect to the acceleration magnitude at the moment of the crash. A. The direction of the initial acceleration vector will point towards the wall, and its magnitude will be less than the acceleration vector of the crash. B. The direction of the initial acceleration vector will point away from the wall, and its magnitude will be less than the vector of the crash. C. The direction of the initial acceleration vector will point towards the wall, and its magnitude will be more than the acceleration vector of the crash. D. The direction of the initial acceleration vector will point away from the wall, and its magnitude will be more than the acceleration vector of the crash.
A. The direction of the initial acceleration vector will point towards the wall, and its magnitude will be less than the acceleration vector of the crash.
A 55-kg lady stands on a bathroom scale inside an elevator. The scale reads 70 kg. What do you know about the motion of the elevator?* A. The elevator must be accelerating upward. B. The elevator must be accelerating downward. C. The elevator must be moving upward with a constant velocity. D. The elevator must be moving downward with a constant velocity.
A. The elevator must be accelerating upward.
A train starts from rest and speeds up for 15 minutes until it reaches a constant velocity of 100 miles/hour. It stays at this speed for half an hour. Then it slows down for another 15 minutes until it is still. Which of the following correctly describes the position vs time graph of the train's journey? A. The first 15 minutes is a curve that is concave upward, the middle portion is a straight line with slope 100 miles/hour, and the last portion is a concave downward curve. B. The first 15 minutes is a curve that is concave downward, the middle portion is a straight line with slope 100 miles/hour, and the last portion is a concave upward curve. C. The first 15 minutes is a curve that is concave upward, the middle portion is a straight line with slope zero, and the last portion is a concave downward curve. D. The first 15 minutes is a curve that is concave downward, the middle portion is a straight line with slope zero, and the last portion is a concave upward curve.
A. The first 15 minutes is a curve that is concave upward, the middle portion is a straight line with slope 100 miles/hour, and the last portion is a concave downward curve.
A hockey puck is shot down the arena in a straight line. Assume it does not slow until it is stopped by an opposing player who sends it back in the direction it came. The players are 20 m apart and it takes 1 s for the puck to go there and back. Which of the following describes the graph of the displacement over time? Consider the initial direction of the puck to be positive. A. The graph is an upward opening V. B. The graph is a downward opening V. C. The graph is an upward opening U. D. The graph is downward opening U.
A. The graph is an upward opening V.
A book with a mass of 0.30 kg falls 2 m from a shelf to the floor. This event is described by the work-energy theorem: W= Fd = 1/2 mv_2^2 −1/2 mv_1^2 Explain why this is enough information to calculate the speed with which the book hits the floor. A. The mass of the book, m, and distance, d, are stated. F is the weight of the book mg . v_1 is the initial velocity and v_2 is the final velocity. The final velocity is the only unknown quantity. B. The mass of the book, m, and distance, d, are stated. F is the weight of the book mg . v_1 is the final velocity and v_2 is the initial velocity. The final velocity is the only unknown quantity. C. The mass of the book, m, and distance, d, are stated. F is the weight of the book mg . v_1 is the initial velocity and v_2 is the final velocity. The final velocity and the initial velocities are the only unknown quantities. D. The mass of the book, m, and distance, d, are stated. F is the weight of the book mg . v_1 is the final velocity and v_2 is the initial velocity. The final velocity and the initial velocities are the only unknown quantities.
A. The mass of the book, m, and distance, d, are stated. F is the weight of the book mg . v_1 is the initial velocity and v_2 is the final velocity. The final velocity is the only unknown quantity.
Two objects rest on a uniform surface. A person pushes both with equal force. If the first object starts to move faster than the second, what can be said about their masses?* A. The mass of the first object is less than that of the second object. B. The mass of the first object is equal to the mass of the second object. C. The mass of the first object is greater than that of the second object. D. No inference can be made because mass and force are not related to each other.
A. The mass of the first object is less than that of the second object.
A student calculated the final velocity of a train that decelerated from 30.5 m/s and got an answer of −43.34 m/s. Which of the following might indicate that he made a mistake in his calculation? A. The sign of the final velocity is wrong. B. The magnitude of the answer is too small. C. There are too few significant digits in the answer. D. The units in the initial velocity are incorrect.
A. The sign of the final velocity is wrong.
3. Velocity, or speed, is measured using the following formula: v = d/t , where v is velocity, d is the distance travelled, and t is the time the object took to travel the distance. If the velocity-time data are plotted on a graph, which variable will be on which axis? Why? A. Time would be on the x-axis and velocity on the y-axis, because time is an independent variable and velocity is a dependent variable. B. Velocity would be on the x-axis and time on the y-axis, because time is the independent variable and velocity is the dependent variable. C. Time would be on the x-axis and velocity on the y-axis, because time is a dependent variable and velocity is a independent variable. D. Velocity would be on x-axis and time on the y-axis, because time is a dependent variable and velocity is a independent variable.
A. Time would be on the x-axis and velocity on the y-axis, because time is an independent variable and velocity is a dependent variable.
Only two forces are acting on an object: force A to the left and force B to the right. If force B is greater than force A, in which direction will the object accelerate? A. To the right B. To the left C. Upward D. The object does not move
A. To the right
Vectors A and B are equal in magnitude and opposite in direction. Does A-B have the same direction as vector A or B? A.Vector A B.Vector B
A. Vector A
What is the slope of a straight line graph of position vs. time? A. Velocity B. Displacement C. Distance D. Acceleration
A. Velocity
A weight is suspended with a rope and hangs freely. In what direction is the tension on the rope? A. parallel to the rope B. perpendicular to the rope
A. parallel to the rope
Which kinematic equation would you use to find the velocity of a skydiver 2.0\,\text{s} after she jumps from a plane and before she opens her parachute? Assume the positive direction is downward. A. v = v_0 + at B. v = v_0 - at C. v^2 = {v_0}^2 + at D. v^2 = {v_0}^2 - at
A. v = v_0 + at
An object has an average speed of 7.4 km/h. Which of the following describes two ways you could increase the average speed of the object to 14.8 km/h? A. Reduce the distance that the object travels by half, keeping the time constant, or keep the distance constant and double the time. B. Double the distance that the object travels, keeping the time constant, or keep the distance constant and reduce the time by half. C. Reduce the distance that the object travels to one-fourth, keeping the time constant, or keep the distance constant and increase the time by fourfold. D. Increase the distance by fourfold, keeping the time constant, or keep the distance constant and reduce the time by one-fourth.
B. Double the distance that the object travels, keeping the time constant, or keep the distance constant and reduce the time by half.
What is dynamics? A. Dynamics is the study of internal forces. B. Dynamics is the study of forces and their effect on motion. C. Dynamics describes the motion of points, bodies, and systems without consideration of the cause of motion. D. Dynamics describes the effect of forces on each other.
B. Dynamics is the study of forces and their effect on motion.
Which statement is NOT an underlying assumption essential to scientific understandings? A. Characteristics of the physical universe can be perceived and objectively measured by human beings. B. Explanations of natural phenomena can be established with absolute certainty. C. Fundamental physical processes dictate how characteristics of the physical universe evolve. D. The fundamental processes of nature operate the same way everywhere and at all times.
B. Explanations of natural phenomena can be established with absolute certainty.
A student is asked to solve a problem: An object falls from a height for 2.0 s, at which point it is still 60 m above the ground. What will be the velocity of the object when it hits the ground? Which of the following provides the correct order of kinematic equations that can be used to solve the problem? A. First use v^2 = v_0 ^2 + 2a (d-d_0 ) , then use v=v_0 + at. B. First use v = v_0 + at, then use v^2 = v_0 ^2 + 2a(d-d_0 ) . C. First use d = d_0 + v_0t + 1/2 at^2 , then use v = v_0 + at. D. First use v = v_0 + at, then use d-d_0 = v_0t + 1/2 at^2 .
B. First use v = v_0 + at, then use v^2 = v_0 ^2 + 2a(d-d_0 )
When is a plot of velocity versus time a straight line and when is it a curved line? A. It is a straight line when acceleration is changing and is a curved line when acceleration is constant. B. It is a straight line when acceleration is constant and is a curved line when acceleration is changing. C. It is a straight line when velocity is constant and is a curved line when velocity is changing. D. It is a straight line when velocity is changing and is a curved line when velocity is constant.
B. It is a straight line when acceleration is constant and is a curved line when acceleration is changing.
What is another name for Newton's first law?* A. Law of infinite motion B. Law of inertia C. Law of friction
B. Law of inertia
What could you conclude about these two lines? Line A has a slope of -4.7. Line B has a slope of 12.0. A. Line A is decreasing while line B is increasing, with line A being much steeper than line B. B. Line A is decreasing while line B is increasing, with line B being much steeper than line A C. Line B is decreasing while line A is increasing, with line A being much steeper than line B. D. Line B is decreasing while line A is increasing, with line B being much steeper than line A.
B. Line A is decreasing while line B is increasing, with line B being much steeper than line A
A person walks 10.0 m north and then 2.0 m east. Solving analytically, what is the resultant displacement of the person? A. Resultant = 10.2 m. Angle theta = 78.7° east of north B. Resultant = 10.2 m. Angle theta = 78.7° north of east C. Resultant = 12.0 m. Angle theta = 78.7° east of north D. Resultant = 12.0 m. Angle theta = 78.7° north of east
B. Resultant = 10.2 m. Angle theta = 78.7° north of east
Can one-dimensional motion have zero distance but a nonzero displacement? What about zero displacement but a nonzero distance? A. One-dimensional motion can have zero distance with a nonzero displacement. Displacement has both magnitude and direction, and it can also have zero displacement with nonzero distance because distance has only magnitude. B. One-dimensional motion can have zero distance with a nonzero displacement. Displacement has both magnitude and direction, but it cannot have zero displacement with nonzero distance because distance has only magnitude. C. One-dimensional motion cannot have zero distance with a nonzero displacement. Displacement has both magnitude and direction, but it can have zero displacement with nonzero distance because distance has only magnitude and any motion will be the distance it moves. D. One-dimensional motion cannot have zero distance with a nonzero displacement. Displacement has both magnitude and direction, and it cannot have zero displacement with nonzero distance because distance has only magnitude.
C. One-dimensional motion cannot have zero distance with a nonzero displacement. Displacement has both magnitude and direction, but it can have zero displacement with nonzero distance because distance has only magnitude and any motion will be the distance it moves.
Are rockets more efficient in Earth's atmosphere or in outer space? Why?* A. Rockets are more efficient in Earth's atmosphere than in outer space because the air in Earth's atmosphere helps to provide thrust for the rocket, and Earth has more air friction than outer space. B. Rockets are more efficient in Earth's atmosphere than in outer space because the air in Earth's atmosphere helps to provide thrust to the rocket, and Earth has less air friction than the outer space. C. Rockets are more efficient in outer space than in Earth's atmosphere because the air in Earth's atmosphere does not provide thrust but does create more air friction than in outer space. D. Rockets are more efficient in outer space than in Earth's atmosphere because the air in Earth's atmosphere does not provide thrust but does create less air friction than in outer space.
C. Rockets are more efficient in outer space than in Earth's atmosphere because the air in Earth's atmosphere does not provide thrust but does create more air friction than in outer space.
Two runners start at the same point and jog at a constant speed along a straight path. Runner A starts at time t = 0 s, and Runner B starts at time t = 2.5 s. The runners both reach a distance 64 m from the starting point at time t = 25 s. If the runners continue at the same speeds, how far from the starting point will each be at time t = 45 s? A. Runner A will be 72 x 10^3 m away and Runner B will be 59.5 x 10^3 m away from the starting point. B. Runner A will be 1.2 x 10^2 m away and runner B will be 1.1 x 10^2 m away from the starting point. C. Runner A will be 1.2 x 10^2 m away and Runner B will be 1.3 x 10^2 m away from the starting point. D. Runner A will be 7.2 x 10^2 m away and Runner B will be 1.3 x 10^2 m away from the starting point.
C. Runner A will be 1.2 x 10^2 m away and Runner B will be 1.3 x 10^2 m away from the starting point.
Which of the following statements explains why a racecar going around a curve is accelerating, even if the speed is constant? A. The car is accelerating because the magnitude as well as the direction of velocity is changing. B. The car is accelerating because the magnitude of velocity is changing. C. The car is accelerating because the direction of velocity is changing. D. The car is accelerating because neither the magnitude nor the direction of velocity is changing.
C. The car is accelerating because the direction of velocity is changing.
A body is pushed eastward by a force of four units and southward by a force of three units. How would you draw a free-body diagram to represent this? A. Two force vectors acting at a point, one pointing left with a length of 4 units and the other pointing down with a length of 3 units B. Two force vectors acting at a point, one pointing left with a length of 4 units and the other pointing up with a length of 3 units C. Two force vectors acting at a point, one pointing right with a length of 4 units and the other pointing down with a length of 3 units D. Two force vectors acting at a point, one pointing right with a length of 4 units and the other pointing up with a length of 3 units
C. Two force vectors acting at a point, one pointing right with a length of 4 units and the other pointing down with a length of 3 units
What is the definition of uncertainty? A. Uncertainty is the number of assumptions made prior to the measurement of a physical quantity. B. Uncertainty is a measure of error in a measurement due to the use of a non-calibrated instrument. C. Uncertainty is a measure of deviation of the measured value from the standard value. D. Uncertainty is a measure of error in measurement due to external factors like air friction and temperature.
C. Uncertainty is a measure of deviation of the measured value from the standard value.
Which graph in the previous problem has a positive slope? A. Displacement versus time only B. Acceleration versus time and velocity versus time C. Velocity versus time and displacement versus time D. Acceleration versus time and displacement versus time
C. Velocity versus time and displacement versus time
Can classical physics be used to accurately describe a satellite moving at a speed of 7500 m/s? Explain why or why not. A. No, because the satellite is moving at a speed much smaller than the speed of the light and is not in a strong gravitational field. B. No, because the satellite is moving at a speed much smaller than the speed of the light and is in a strong gravitational field. C. Yes, because the satellite is moving at a speed much smaller than the speed of the light and it is not in a strong gravitational field. D. Yes, because the satellite is moving at a speed much smaller than the speed of the light and is in a strong gravitational field.
C. Yes, because the satellite is moving at a speed much smaller than the speed of the light and it is not in a strong gravitational field.
In which example would you be correct in describing an object in motion while your friend would also be correct in describing that same object as being at rest? A. You are driving a car toward the east and your friend drives past you in the opposite direction with the same speed. In your frame of reference, you will be in motion. In your friend's frame of reference, you will be at rest. B. You are driving a car toward the east and your friend is standing at the bus stop. In your frame of reference, you will be in motion. In your friend's frame of reference, you will be at rest. C. You are driving a car toward the east and your friend is standing at the bus stop. In your frame of reference, your friend will be moving toward the west. In your friend's frame of reference, he will be at rest. D. You are driving a car toward the east and your friend is standing at the bus stop. In your frame of reference, your friend will be moving toward the east. In your friend's frame of reference, he will be at rest.
C. You are driving a car toward the east and your friend is standing at the bus stop. In your frame of reference, your friend will be moving toward the west. In your friend's frame of reference, he will be at rest.
What conditions imply that we can use classical physics without considering special relativity or quantum mechanics? A. (1) matter is moving at speeds of less than roughly 1 percent the speed of light, (2) objects are large enough to be seen with the naked eye, and (3) there is the involvement of a strong gravitational field. B. (1) matter is moving at speeds greater than roughly 1 percent the speed of light, (2) objects are large enough to be seen with the naked eye, and (3) there is the involvement of a strong gravitational field. C. (1) matter is moving at speeds of less than roughly 1 percent the speed of light, (2) objects are too small to be seen with the naked eye, and (3) there is the involvement of only a weak gravitational field. D. (1) matter is moving at speeds of less than roughly 1 percent the speed of light, (2) objects are large enough to be seen with the naked eye, and (3) there is the involvement of a weak gravitational field.
D. (1) matter is moving at speeds of less than roughly 1 percent the speed of light, (2) objects are large enough to be seen with the naked eye, and (3) there is the involvement of a weak gravitational field.
A marathon runner completes a 42.188-km course in 2 h, 30 min, and 12 s. There is an uncertainty of 25 m in the distance traveled and an uncertainty of 1 s in the elapsed time. 1) Calculate the percent uncertainty in the distance; 2) Calculate the uncertainty in the elapsed time; 3) What is the average speed in meters per second?; 4) What is the uncertainty in the average speed? A. 0.059%, 0.01%, 0.468 m/s, 0.0003 m/s B. t0.059%, 0.01%, 0.468 m/s, 0.07 m/s C. 0.59%, 8.33%, 4.681 m/s, 0.003 m/s D. 0.059%, 0.01%, 4.681 m/s, 0.003 m/s
D. 0.059%, 0.01%, 4.681 m/s, 0.003 m/s
A swimmer bounces straight up from a diving board and falls feet first into a pool. She starts with a velocity of 4.00\,\text{m/s} and her takeoff point is 8\,\text{m} above the pool. How long are her feet in the air? A. 0.408 s B. 0.816 s C. 1.34 s D. 1.75 s E. 1.28 s
D. 1.75 s
You throw a ball straight up with an initial velocity of 15.0 m/s. It passes a tree branch on the way up at a height of 7.00 m. How much additional time will pass before the ball passes the tree branch on the way back down? A. 0.574 s B. 0.956 s C. 1.53 s D. 1.91 s
D. 1.91 s
A person pushes an object of mass 5.0 kg along the floor by applying a force. If the object experiences a friction force of 10 N and accelerates at 18 m/s^2, what is the magnitude of the force exerted by the person? A. −90 N B. −80 N C. 90 N D. 100 N
D. 100 N
A car accelerates from rest at a stop sign at a rate of 3.0 m/s^2 to a speed of 21.0 m/s, and then immediately begins to decelerate to a stop at the next stop sign at a rate of 4.0 m/s^2. How long did it take the car to travel from the first stop sign to the second stop sign? A. 1.7 seconds B. 5.3 seconds C. 7.0 seconds D. 12 seconds
D. 12 seconds
The length and width of a rectangular room are measured to be 3.955 ± 0.005 m by 3.050 ± 0.005 m. Calculate the area of the room and its uncertainty in square meters. A. 12.06 ± 0.29 m^2 B. 12.06 ± 0.01 m^2 C. 12.06 ± 0.25 m^2 D. 12.06 ± 0.04 m^2
D. 12.06 ± 0.04 m^2
A car engine moves a piston with a circular cross section diameter of 7.500 ± 0.002 cm, at a distance of 3.250 ± 0.001 cm to compress the gas in the cylinder. By what amount did the gas decrease in volume in cubic centimeters? Find the uncertainty in this volume. A. 143.6 ± 0.002 cm^3 B. 143.6 ± 0.003 cm^3 C. 143.6 ± 0.005 cm^3 D. 143.6 ± 0.1 cm^3
D. 143.6 ± 0.1 cm^3
What is the magnitude of a vector whose x-component is 2 units and whose angle is 60° A. 1.0 units B. 2.0 units C. 2.3 units D. 4.0 units
D. 4.0 units
A 65-kg swimmer pushes on the pool wall and accelerates at 6 m/s^2. The friction experienced by the swimmer is 100 N. What is the magnitude of the force that the swimmer applies on the wall? A. −490 N B. −290 N C. 290 N D. 490 N
D. 490 N
A swan on a lake gets airborne by flapping its wings and running on top of the water. If the swan must reach a velocity of 6.00 m/s to take off and it accelerates from rest at an average rate of 0.350 m/s^2, how far will it travel before becoming airborne? A. −8.60 m B. 8.60 m C. −51.4 m D. 51.4 m
D. 51.4 m
A water balloon cannon is fired at 30 m/s at an angle of 50° above the horizontal. How far away will it fall? A. 2.35 m B. 3.01 m C. 70.35 m D. 90.44 m
D. 90.44 m
