Exam 1

A) The velocity is positive, but the acceleration is zero.

Consider a position-time graph that consists of a single line segment of positive slope. Which one of the following is true? A) The velocity is positive, but the acceleration is zero. B) The velocity is negative, but the acceleration is zero. C) The velocity and acceleration are negative. D) The velocity and acceleration are positive.

B) Both II and III change.

A body is moved from sea level to the top of a high mountain. Which of the following statements is/are true concerning the following quantities? I. The body's mass. II. The body's weight. III. The gravitational force on the body. A) Only I changes. B) Both II and III change. C) Both I and III change. D) Only III changes. E) Only II changes.

curved down to the right

An apple tree is being moved on the back of a flatbed truck at constant speed from left to right, when an observer on the truck sees an apple fall from the tree and fall straight down. What path would an observer at rest on the ground see the falling apple follow?

A) A distance of 10 km in a direction of 30° north of west

The following figure shows the displacement vector of a car. Which of the following is the correct description of this vector? Image: 30 degrees above the -x axis, 10 km long A) A distance of 10 km in a direction of 30° north of west B) None of the above is a correct description of the displacement vector. C) A distance of 10 km in a direction of 60° north of west D) A distance of 10 km in a direction of 30° east of north E) A distance of 10 km

C) Newton's third law is also known as the action/reaction law.

Which of the following statements is true? A) Newton's third law is only valid for contact forces. B) Newton's third law states that for every acceleration of one object, there is an equal but opposite acceleration of another object. C) Newton's third law is also known as the action/reaction law. D) Newton's third law is also known as F=ma.

C) Its velocity will eventually pass through zero, reverse direction, and continue to accelerate in the opposite direction.

A car undergoes a constant deceleration (the acceleration is opposite to its velocity). Which statement is true of the car assuming a truly constant (negative) acceleration? A) It will not come to a halt, and will not reverse direction. B) It will eventually come to a permanent halt. C) Its velocity will eventually pass through zero, reverse direction, and continue to accelerate in the opposite direction.

B) Yes, the car's average speed was 72 m.p.h.

A cop gets a call indicating that a red sports car passed mile marker 3 on a highway with a speed limit of 60 m.p.h. Exactly five minutes later the car passes the cop, who is sitting at mile marker number 9. Even though the cop's radar indicates that the car is going the speed limit, was the car speeding at any point between markers 3 and 9? A) No. There is no way to prove the driver broke the speed limit. B) Yes, the car's average speed was 72 m.p.h. C) Yes, the car was going at least 90 m.p.h.

B) 4r and 2v

A powerboat, starting from rest maintains a constant acceleration. After a certain time t, its displacement and velocity are r and v. At time 2t, what will be its displacement and velocity, assuming the acceleration remains constant? A) 2r and 2v B) 4r and 2v C) 2r and 4v D) 4r and 4v

E) -g m/s2

A projectile is launched in the air and follows the parabolic path shown. When it reaches the peak in its trajectory, what is the acceleration of the projectile? A) -g/2 m/s2 B) 0 C) It depends on the projectile's launch angle. D) It depends on the projectile's initial speed. E) -g m/s2

B) The velocity is zero, and the acceleration is -g.

A rock is thrown vertically. What is true when the rock reaches its maximum height? A) The velocity is zero, and the acceleration is zero. B) The velocity is zero, and the acceleration is -g. C) The velocity equals half its initial velocity, and the acceleration is zero. D) The velocity equals half its initial velocity, and the acceleration is -g.

C) The floor provides a normal force vertically upward (perpendicular to the floor) on each leg with a magnitude of 100 N.

A square, four-legged table with a weight of 400 N rests on an even concrete floor. Assuming the weight is evenly distributed, what is the direction and magnitude of the normal force between the floor and each foot of the table? A) The floor provides a force vertically upward (perpendicular to the floor) on each leg with a magnitude of 400 N. B) The floor provides a force parallel to the floor on each leg with a magnitude of 400 N. C) The floor provides a normal force vertically upward (perpendicular to the floor) on each leg with a magnitude of 100 N. D) The floor provides a normal force parallel to the floor on each leg with a magnitude of 100 N.

A) Different B) Different C) Same

A stone is thrown horizontally from the top of a cliff and eventually hits the ground below. A second stone is dropped from rest from the same cliff, falls through the same height, and also hits the ground below. Consider the three quantities below. Are they the same for the two stones, or different? (a) Displacement (b) Speed just before impact with the ground (c) Time of flight

A) The velocity vector of the object is directed at an angle greater than 45° above the positive x-axis.

At t=0, an object is moving with constant velocity in the xy-plane, where its velocity vector makes an angle of 45° relative to the positive x-axis. The object then accelerates for 2 seconds in the positive y-direction only. After the 2 seconds, which of the following is true? A) The velocity vector of the object is directed at an angle greater than 45° above the positive x-axis. B) The velocity vector of the object is directed at an angle less than 45° above the positive x-axis. C) The velocity of the object is zero. D) The velocity vector of the object is still directed at 45° above the positive x-axis.

Yes

Below is a list of variables and their corresponding units. x Meters (m) v Meters per second (m/s) t Seconds (s) a Meters per second squared (m/s2) Consider the following relationship: t = sqrt(2x/a). Is this relationship dimensionally consistent? In other words, do the units on the left side of the equation match the units on the right side? Yes or No

No

Can two nonzero perpendicular vectors be added together so their sum is equal to zero? Yes or No

B) No. The curve represents a non-constant acceleration, and the kinematic equations were derived assuming a constant acceleration.

Consider a velocity-time graph that consists of a curve rather than a line of constant slope. Can you use the equations of kinematics to describe the motion of an object undergoing motion described by such a graph? A) Yes. The velocity-time graph will give a constant acceleration regardless of whether it is a line or a complex curve. B) No. The curve represents a non-constant acceleration, and the kinematic equations were derived assuming a constant acceleration. C) Yes, as long as the acceleration is positive. D) Yes. The kinematic equations apply under all circumstances.

E) 5.74 × 10-4 m

Consider the value 0.000574 m. Which of the following choices correctly represents this quantity written in scientific notation? A) 5.74 × 10-3 m B) 0.000574 m C) 5.74 × 103 m D) 0.574 × 103 m E) 5.74 × 10-4 m

D) sqrt(Cx^2+Cy^2)

Consider the vector equation A+B=C. The component method of vector addition specifies that the scalar components of the resultant vector C are given by Cx=Ax+Bx and Cy=Ay+By. Which of the following would give the magnitude of the resultant vector C? A) Cx+Cy B) Cx-Cy C) Cx^2+Cy^2 D) sqrt(Cx^2+Cy^2) E) None of the above

B) The electroweak force because the bonding in materials is carried out by electrons (electric charges).

Considering that there are only three fundamental forces in nature from which all other forces can be derived, which of the three are responsible for the forces between atoms that hold solid materials together? A) It is the gravitational attraction (the gravitational force) between the atoms. B) The electroweak force because the bonding in materials is carried out by electrons (electric charges). C) It is the nuclear strong force between the nucleons in the nuclei of the atoms.

D) Yes. Whenever one of the variables is squared, that equation may provide two possible solutions. There are two such equations: x=v0t+1/2at^2 and v^2=v0^2+2ax

Of the four kinematic equations, is it possible to get two possible solutions from the same equation? If so, which ones? A) No. One equation can never give two solutions. B) Yes. Only v=v0+at. C) Yes. They all can give two solutions. D) Yes. Whenever one of the variables is squared, that equation may provide two possible solutions. There are two such equations: x=v0t+1/2at^2 and v^2=v0^2+2ax

B) The average speeds are the same, but the average velocities are different.

Suppose you drive 1500 m due east in 2 minutes. You then turn due north and drive the same distance in the same time. Which of the following is true concerning the average speeds and average velocities for each segment of your trip? A) The average speeds are different, and the average velocities are different. B) The average speeds are the same, but the average velocities are different. C) The average speeds are the same, and the average velocities are the same. D) The average speeds are different, but the average velocities are the same.

B) The initial velocity of the object is zero.

The phrase "it starts from rest" appears in statement of a kinematics problem regarding the motion of an object. What can you infer from this statement? A) The final velocity of the object is zero. B) The initial velocity of the object is zero. C) The acceleration of the object is negative. D) None of the above.

C) On the corners of an equilateral triangle.

Three particles have identical masses. Each particle experiences only the gravitational forces from the other two particles. How should the particles be arranged so that each one experiences a net gravitational force of the same magnitude? A) On the corners of a right triangle. B) On three of the four corners of a square. C) On the corners of an equilateral triangle. D) Equally spaced on a straight line.

C) The acceleration for the aircraft carrier launch is 5 times that of the land-based takeoff.

To attain its takeoff speed, the typical land-based takeoff distance for a certain fighter jet is 500 m. On an aircraft carrier, that same jet must takeoff at a reduced distance of 100 m, so the jet gets "assisted" by a steam-driven catapult. Assuming a constant acceleration in both cases, how does the magnitude of the acceleration of the jet when taking off from the carrier compare to its acceleration when it takes off from the land-based runway? A) The acceleration for the aircraft carrier launch is 25 times that of the land-based takeoff. B) The two accelerations must be exactly the same. C) The acceleration for the aircraft carrier launch is 5 times that of the land-based takeoff. D) The acceleration for the aircraft carrier launch is 1/5 that of the land-based takeoff.

E) Vectors A and B are collinear and point in the same direction.

Vectors A, B and C satisfy the following equation A+B=C, and their magnitudes are related by the scalar equation A+B=C. How is vector A oriented with respect to vector B? A) There is no way to tell the orientation of vectors A and B from the given information. B) Vectors A and B are perpendicular to each other. C) Vectors A and B are collinear and point in opposite directions. D) Vectors A and B can only be equal to zero. E) Vectors A and B are collinear and point in the same direction.

B) The displacement will be less than or equal to the total distance.

Which of the following is true concerning the relationship between the total distance an object moves and the displacement of the object? A) The total distance is always less than the displacement. B) The displacement will be less than or equal to the total distance. C) The total distance and displacement are always equal. D) The displacement is always less than the total distance. E) The total distance will be less than or equal to the displacement.

A) II and IV only

Which of the following is/are true? I. Force is a scalar quantity. II. Force is a vector quantity. III. A force is a push or a pull between objects that occurs only when the objects are in physical contact. IV. Non-contact forces are also called action-at-a-distance forces. A) II and IV only B) I and III only C) II only D) II and III only E) I only

A) II, III, and V only

Which of the following is/are true? I. Mass is a vector quantity. II. Mass is a scalar quantity. III. Mass is a measure of how much matter an object contains. IV. There is no relationship between force and mass. V. Isaac Newton developed three important laws of motion that describe the relationship between force and mass. A) II, III, and V only B) II, III, and IV only C) II and III only D) II, IV, and V only E) I and III only

E) All of the above statements are true.

Which of the following statements is/are true? A) Physics is the most fundamental of all the branches of science. B) Physics is a very mature science, where its fundamental principles have been tested over many centuries and supported by empirical evidence from experimentation. C) Physics provides a framework for explaining the processes of the natural world. D) Physics research has had a significant impact on the development of new technologies, such as space travel, telecommunications, and medicine. E) All of the above statements are true.

A) There is no net force acting on the jet.

Which statement is true regarding a jet moving at a constant speed of 450 m.p.h. in straight and level flight. A) There is no net force acting on the jet. B) With no net force, the jet would lose altitude. C) There is a net force acting on the jet, but only in the upward direction - otherwise it could not maintain flight. D) With no net force, the jet would eventually slow down.

C) A nonzero net external force acts on the object in Case B only.

In Case A, an object is moving in a straight line at a constant speed of 9.8 m/s. In Case B, an object is moving in a straight line with a constant acceleration of 9.8 m/s2. Which of the following statements is true? A) A nonzero net external force acts on the object in neither case. B) A nonzero net external force acts on the object in Case A only. C) A nonzero net external force acts on the object in Case B only. D) A nonzero net external force acts on the object in both cases.

D) The mass is the same everywhere.

In which location does a 15-kg bowling ball have the smallest mass? A) On the moon where the force due to gravity is less than on earth. B) On Earth. C) In deep space where there is no force due to gravity. D) The mass is the same everywhere.

D) First, use the three given variables to obtain v0, and then use a second equation to find the unknown variable asked for in the problem.

Note that all of the kinematic equations contain the initial velocity, v0. If a problem gives you three kinematic variables that do not including v0, and you are asked to find a variable other than v0, how should you proceed? A) The problem statement must be incomplete. B) There must be implied information that was missed. C) There is no procedure, the problem is not solvable. D) First, use the three given variables to obtain v0, and then use a second equation to find the unknown variable asked for in the problem.

D) The magnitude of the displacement is less than the total distance traveled, and the resultant displacement vector points south.

A deer runs north 500 m, then turns south and runs 750 m. Which statement is true? A) The magnitude of the displacement is equal to the total distance traveled, and the resultant displacement vector points south. B) The magnitude of the displacement is zero. C) The magnitude of the displacement is equal to the total distance traveled, and the resultant displacement vector points north. D) The magnitude of the displacement is less than the total distance traveled, and the resultant displacement vector points south.

D) 112 m due east

A displacement vector r has a magnitude of 175 m directed at an angle of 50° north of east. What is the x-component of this displacement vector? Image: 50 degrees above the +x axis, 175m long A) 134 m due north B) 175 m C) 112 m D) 112 m due east E) 134 m due east

A) I and IV only

A father and his seven-year-old daughter are facing each other on ice skates. With their hands, they push off against one another. Which of the following statements is/are true? I. Each experiences an acceleration that has a different magnitude. II. Each experiences an acceleration that has the same magnitude. III. Each experiences a pushing force that has a different magnitude. IV. Each experiences a pushing force that has the same magnitude. A) I and IV only B) I and III only C) II and III only D) II and IV only

D) Its average speed was 50 m.p.h, its displacement was zero, and its average velocity was zero.

A new car leaves a parking lot with its odometer indicating 23 miles. Two hours later it returns with an odometer reading of 123 miles. Which statement is true of the car's trip? A) Its average speed was zero, its displacement was zero, and its average velocity was 50 m.p.h. B) Its average speed was 50 m.p.h, its displacement was 100 miles, and its average velocity was zero. C) Its average speed was zero, its displacement was 100 miles, and its average velocity was 50 m.p.h. D) Its average speed was 50 m.p.h, its displacement was zero, and its average velocity was zero.

B) The magnitude of the maximum static friction force on the crate is 1.4 times as large as the kinetic friction force.

Suppose the coefficients of static and kinetic friction have values such that us=1.4uk for a crate in contact with a cement floor. Which of the following statements is true? A) The magnitude of the kinetic friction force on the crate is always 1.4 times as large as the static friction force. B) The magnitude of the maximum static friction force on the crate is 1.4 times as large as the kinetic friction force. C) The magnitude of the static friction force on the crate is always 1.4 times as large as the kinetic friction force.

C) Swimmer A

Three swimmers can swim equally fast relative to the water. They have a race to see who can swim across a flowing river in the least time. Swimmer A swims perpendicular to the current and lands on the opposite shore downstream, because the current has swept him in that direction. Swimmer B swims upstream at angle to the current, so that when she reaches the other side, she is straight across from where she started. Swimmer C swims downstream at an angle theta in an attempt to take advantage of the current. Who crosses the river in the least time? A) Swimmer C B) All three swimmers cross the river in the same time. C) Swimmer A D) Swimmer B

True

True or False: If the magnitudes of both the x- and y-component of a vector are doubled, then the magnitude of the vector is also doubled.

C) A car's speedometer and compass reading of 65 mi/h due east

Which of the following is an example of a vector quantity? A) A time of 7.9 s B)A car's speedometer reading of 65 mi/h C) A car's speedometer and compass reading of 65 mi/h due east D) A temperature of +20 °C E) An object's mass of 34 kg

D) ATT (Angles, Temperature, Time)

Which of the following is not a system of units used in measurements? A) SI (System International) B) CGS (Centimeter, Gram, Second) C) BE (British Engineering) D) ATT (Angles, Temperature, Time) E) None of these is a system of units.

B) The ball project downward will hit first, but the two will hit with equal velocities.

You and a friend are standing on the edge of a cliff of height h. You throw a ball straight upward at the same time your friend throws a ball straight downward, off the edge. You both throw with the same initial speed, v0. Assuming the ball projected upward misses the edge of the cliff on the way down, which ball will hit the ground first, and which one will hit with the greater velocity? A) The ball projected upward reverses course, catches up and passes the ball initially projected downward, and hits the ground first, and with the greatest velocity. B) The ball project downward will hit first, but the two will hit with equal velocities. C) The ball projected downward will hit first and with the greatest velocity.

A) Your apparent weight is less than your true weight.

You are standing on a scale and in a fast elevator that is taking you to the top of a tall building. The elevator slows as it reaches the top. What is true of your apparent weight as the elevator decelerates? A) Your apparent weight is less than your true weight. B) Your apparent weight is equal to your true weight. C) Your apparent weight is greater than your true weight.

A) Accelerating downward, stationary, accelerating upward

A box is at rest on the floor of an elevator. Because of static friction, a force is required to start the box sliding across the elevator floor. Compare the size of the pushing force required to move the box, when the elevator is (a) stationary, (b) accelerating upward, and (c) accelerating downward. Rank these forces from smallest to largest. A) Accelerating downward, stationary, accelerating upward B) Stationary, accelerating downward, accelerating upward C) Stationary, accelerating upward, accelerating downward D) Accelerating upward, stationary, accelerating downward

x=v0t+1/2at^2

A kinematics problem asks for the value of the acceleration and provides values for x, t, and the initial velocity. Which equation should you use?

B) 125 m

Imagine you are confined to the floor of gymnasium that is 100 meters long and 75 meters wide. Starting at any one of the corners, what is your maximum possible displacement? A) 75 meters B) 125 m C) 100 meters D) No limit

B) The object can be either stationary or traveling with constant velocity.

The net external force acting on an object is zero. Which of the following statements is/are true? A) The object can only be stationary. B) The object can be either stationary or traveling with constant velocity. C) The object can only be traveling with a velocity that is changing. D) The object can only be traveling with a constant velocity.

False

True or False: It is ok to add different units together, as long as they have the same dimensions. For example, while 25 mi and 12 km have different units, we can add them together (without conversion) since they both have the dimension of length.