Physics Final Exam

In non-uniform circular motion, the acceleration vector always points toward the center of the circle. Select one: True False

The correct answer is 'False'.

In uniform circular motion problems, angles measured from the positive x-axis in a clockwise direction are considered to be positive angles. Select one: True False

The correct answer is 'False'.

The normal force is always equal to the gravitational force, just in an opposite direction. Select one: True False

The correct answer is 'False'.

For an inclined plane problem, the free-fall acceleration can be broken into two parts--the part perpendicular to the plane and the part parallel to the plane. Select one: True False

The correct answer is 'True'

An object in equilibrium can be moving. Select one: True False

The correct answer is 'True'.

The piece of the acceleration that we'll need to solve our inclined plane problems is the piece that is parallel to the plane (for now). Select one: True False

The correct answer is 'True'.

For a particle with uniform circular motion, the perpendicular component of the velocity will always be zero. Select one: True False

The correct answer is 'False'.

A 1000-kg car is slowly picking up speed as it goes around a horizontal curve whose radius is 100 m. The coefficient of static friction between the tires and the road is 0.350. At what speed will the car begin to skid sideways? Select one: A. 9.25 m/s B. 18.5 m/s C. 34.3 m/s D. 35.0 m/s E. 23.6 m/s

The correct answer is: 18.5 m/s

If the mass of the earth and all objects on it were suddenly doubled, but the size remained the same, the acceleration due to gravity at the surface would become Select one: A. the same as it now is. B. 1/4 of what it now is. C. 4 times what it now is. D. 1/2 of what it now is. E. 2 times what it now is.

The correct answer is: 2 times what it now is.

If you swing a bucket of water fast enough in a vertical circle, at the highest point the water does not spill out because an outward force balances the pull of gravity on the water. Select one: A. True B. False

The correct answer is: False

In order to get an object moving, you must push harder on it than it pushes back on you. Select one: A. True B. False

The correct answer is: False

In order to lift a bucket of concrete, you must pull up harder on the bucket than it pulls down on you. Select one: A. True B. False

The correct answer is: False

Who discovered three laws governing planetary orbits? Select one: Newton Kepler Faraday Einstein Copernicus

The correct answer is: Kepler

A ball is tossed straight up in the air. At its very highest point, the ball's acceleration vector Select one: Points up. Is zero. Points down.

The correct answer is: Points down.

In physics, what is the difference between "speed" and "velocity"? Select one: Velocity is represented by an exact number, while speed is only an approximate number. Speed can be positive or negative, while velocity is always positive. Speed is a scalar, which is the magnitude of the velocity, which is a vector. Velocity is a scalar and speed is a vector.

The correct answer is: Speed is a scalar, which is the magnitude of the velocity, which is a vector.

A baseball is located at the surface of the earth. Which statement about it is correct? Select one: A. The gravitational force on the ball due to the earth is exactly the same as the gravitational force on the earth due to the ball. B. The earth exerts a much greater gravitational force on the ball than the ball exerts on the earth. C. The ball exerts a greater gravitational force on the earth than the earth exerts on the ball. D. The gravitational force on the ball is independent of the mass of the earth. E. The gravitational force on the ball is independent of the mass of the ball.

The correct answer is: The gravitational force on the ball due to the earth is exactly the same as the gravitational force on the earth due to the ball.

Consider what happens when you jump up in the air. Which of the following is the most accurate statement? Select one: A. Since the ground is stationary, it cannot exert the upward force necessary to propel you into the air. Instead, it is the internal forces of your muscles acting on your body itself that propels your body into the air. B. When you push down on the earth with a force greater than your weight, the earth will push back with the same magnitude force and thus propel you into the air. C. When you jump up the earth exerts a force F1 on you and you exert a force F2 on the earth. You go up because F1 > F2. D. It is the upward force exerted by the ground that pushes you up, but this force cannot exceed your weight. E. You are able to spring up because the earth exerts a force upward on you that is greater than the downward force you exert on the earth.

The correct answer is: When you push down on the earth with a force greater than your weight, the earth will push back with the same magnitude force and thus propel you into the air.

Rank in order, from the most to the least, the number of significant figures in the following numbers. For example, if b has more than c, c has the same number as a, and a has more than d, you would give your answer as b > c = a > d. a. 8200 b. 0.0052 c. 0.430 d. 4.321 × 10-10 Select one: d > c > b = a a = b = d > c b = d > c > a d > c > a > b a = d > c > b

The correct answer is: d > c > b = a

You swing a bat and hit a heavy box with a force of 1500 N. The force the box exerts on the bat is Select one: A. exactly 1500 N only if the box does not move. B. greater than 1500 N if the box moves. C. less than 1500 N if the box moves. D. exactly 1500 N whether or not the box moves. E. greater than 1500 N if the bat bounces back.

The correct answer is: exactly 1500 N whether or not the box moves.

An object is moving to the right, and experiencing a net force that is directed to the right. The magnitude of the force is decreasing with time. The speed of the object is Select one: A. increasing. B. constant in time. C. decreasing.

The correct answer is: increasing.

A brick is resting on a rough incline as shown in the figure. The friction force acting on the brick, along the incline, is Select one: A. zero. B. less than the weight of the brick. C. greater than the weight of the brick. D. equal to the weight of the brick.

The correct answer is: less than the weight of the brick.

Robert pushes the box to the left at constant speed. In doing so, Robert does ______ work on the box. Select one: positive negative zero

The correct answer is: positive

A string is attached to the rear-view mirror of a car. A ball is hanging at the other end of the string. The car is driving around in a circle, at a constant speed. Which of the following lists gives all of the forces directly acting on the ball? Select one: A. tension, gravity, the centripetal force, and friction B. tension, gravity, and the centripetal force C. tension D. tension and gravity

The correct answer is: tension and gravity

When a parachutist jumps from an airplane, he eventually reaches a constant speed, called the terminal speed. Once he has reached terminal speed Select one: A. the force of air drag on him is equal to g. B. his speed is equal to g. C. his acceleration is equal to g. D. the force of air drag on him is equal to his weight. E. the force of air drag on him is equal to zero.

The correct answer is: the force of air drag on him is equal to his weight.

A new way of multiplying two vectors is introduced in Chapter 12. What is it called? Select one: The dot product. The scalar product. The tensor product. The cross product. The angular product.

The correct answer is: The cross product.

A ball is tossed vertically upward. When it reaches its highest point (before falling back downward) Select one: A. the velocity is zero, the acceleration is zero, and the force of gravity acting on the ball is zero. B. the velocity is zero, the acceleration is directed downward, and the force of gravity acting on the ball is directed downward. C. the velocity is zero, the acceleration is zero, and the force of gravity acting on the ball is directed downward. D. the velocity, acceleration, and the force of gravity on the ball all reverse direction. E. the velocity and acceleration reverse direction, but the force of gravity on the ball remains downward.

The correct answer is: the velocity is zero, the acceleration is directed downward, and the force of gravity acting on the ball is directed downward.

A box slides down a frictionless plane inclined at an angle θ above the horizontal. The gravitational force on the box is directed Select one: A. parallel to the plane in the opposite direction as the movement of the box. B. perpendicular to the plane. C. vertically. D. parallel to the plane in the same direction as the movement of the box. E. at an angle θ below the inclined plane.

The correct answer is: vertically.

A stalled car is being pushed up a hill at constant velocity by three people. The net force on the car is Select one: A. up the hill and greater than the weight of the car. B. up the hill and equal to the weight of the car. C. down the hill and greater than the weight of the car. D. zero. E. down the hill and equal to the weight of the car.

The correct answer is: zero.

A 3.2 kg box is pushed across the floor at constant velocity. If the push force is 10 N and there is friction, what is the box's acceleration? Select one: a. 0 m/s2 b. 3.1 m/s2 c. 0.32 m/s2 d. I need to know the frictional force to answer this question.

The correct answer is: 0 m/s2

A ball on a massless, rigid rod oscillates as a simple pendulum with a period of 2.0 s. If the ball is replaced with another ball having twice the mass, the period will be Select one: 1.0 s 1.4 s 2.0 s 2.8 s 4.0 s

The correct answer is: 2.0 s

A mass oscillates on a horizontal spring with a period T = 2.0 s. If the amplitude of the oscillation is doubled, the new period will be Select one: 1.0 s 1.4 s 2.0 s 2.8 s 4.0 s

The correct answer is: 2.0 s

Which of the following does not necessarily describe an object in equilibrium? Select one: a. An object has no net force acting on it. b. An object has a zero acceleration. c. An object has a constant velocity. d. An object is not moving in the y-direction.

The correct answer is: An object is not moving in the y-direction

When floating in space with no external forces acting on it, an object tends to rotate about its Select one: Axle. Center of mass. Edge. Geometrical center. Pivot point.

The correct answer is: Center of mass.

What is the geometric shape of a planetary or satellite orbit? Select one: Circle Hyperbola Sphere Parabola Ellipse

The correct answer is: Ellipse

A method for keeping track of transformations between kinetic energy and gravitational potential energy, introduced in Chapter 10, is Select one: Credit-debit tables. Kinetic energy-versus-time graphs. Energy bar charts. Energy conservation pools. Energy spreadsheets.

The correct answer is: Energy bar charts.

The total momentum of a system is conserved Select one: If the system is isolated. Always. If the forces are conservative. Never; it's just an approximation.

The correct answer is: If the system is isolated.

A rotating object has some rotational kinetic energy. If its angular speed is doubled, but nothing else changes, the rotational kinetic energy Select one: Increases by a factor of 4. Doubles. Does not change. Halves. Decreases by a factor of 4

The correct answer is: Increases by a factor of 4.

The centrifugal force Select one: Is a fictitious force. Points toward the center of the circle. Is provided by static friction. All of the above. Points toward the center of the circle and is provided by static friction.

The correct answer is: Is a fictitious force.

When drag is included, the launch angle of a projectile which maximizes the range is Select one: Greater than 45º. Equal to 45º. Less than 45º.

The correct answer is: Less than 45º.

Gravitational potential energy is Select one: The area under a gravity force-versus-time graph. The gravitation constant times mass-squared divided by distance-squared. Mass times the acceleration due to gravity times vertical position. ½ mass times speed-squared. Velocity per unit mass.

The correct answer is: Mass times the acceleration due to gravity times vertical position.

Momentum is Select one: Mass times velocity. ½ mass times speed-squared. The area under the force curve in a force-versus-time graph. Velocity per unit mass.

The correct answer is: Mass times velocity.

A method for "momentum accounting," introduced in Chapter 11, is Select one: Momentum bar charts. Credit-debit tables. Impulse-versus-time graphs. Momentum conservation pools. Momentum spreadsheets.

The correct answer is: Momentum bar charts.

For uniform circular motion, the net force Select one: Points toward the center of the circle. Points toward the outside of the circle. Is tangent to the circle. Is zero.

The correct answer is: Points toward the center of the circle.

A block oscillates on a vertical spring. When the block is at the lowest point of the oscillation, it's acceleration ay is Select one: Negative. Zero. Positive.

The correct answer is: Positive.

The gravitational force between two objects of masses m1 and m2 that are separated by distance r is Select one: Proportional to r Proportional to 1/r2 (m1 + m2)g (m1 + m2)G

The correct answer is: Proportional to 1/r2

The value of g at the height of the space station's orbit is Select one: 9.8 m/s2 Slightly less than 9.8 m/s2 Much less than 9.8 m/s2 Exactly zero

The correct answer is: Slightly less than 9.8 m/s2

Impulse is Select one: The area under the force curve in a force-versus-time graph. A force that is applied at a random time. A force that is applied very suddenly. The time interval that a force lasts.

The correct answer is: The area under the force curve in a force-versus-time graph.

Mechanical energy is Select one: The energy due to internal moving parts. The energy of motion. The energy of position. The sum of kinetic energy plus potential energy. The sum of kinetic, potential, thermal, and elastic energy.

The correct answer is: The sum of kinetic energy plus potential energy.

A skier is gliding down a slope at a constant speed. What energy transformation is taking place? Select one: K → U U → K Eth → K U → Eth K → Eth

The correct answer is: U → Eth

A crane lowers a girder into place at constant speed. Consider the work WG done by gravity and the work WT done by the tension in the cable. Which is true? Select one: WG > 0 and WT > 0 WG > 0 and WT < 0 WG < 0 and WT > 0 WG < 0 and WT < 0 WG = 0 and WT = 0

The correct answer is: WG > 0 and WT < 0

The instantaneous velocity at time t is... Select one: a. the slope of the line that is tangent to the position-versus-time graph at any time t. b. the same as the speed. c. the distance traveled divided by the time interval.

The correct answer is: a. the slope of the line that is tangent to the position-versus-time graph at any time t.

For uniform circular motion, the instantaneous velocity and acceleration vectors always Select one: a. point in the same direction b. point in opposite directions c. are perpendicular to one another d. make an angle with one another that depends on the specific motion of the particle

The correct answer is: are perpendicular to one another

In uniform circular motion, an acceleration vector that points directly toward the center of a circle is referred to as Select one: a. zero acceleration b. tangential acceleration c. centripetal acceleration

The correct answer is: centripetal acceleration

Uniform circular motion requires that a particle move around a circular path with Select one: a. constant speed b. increasing speed c. decreasing speed

The correct answer is: constant speed

Which of the following is NOT TRUE of uniform motion? Select one: a. Uniform motion has equal displacements over equal time intervals. b. The position-versus-time graph is a straight line in uniform motion. c. The velocity is constant and unchanging in uniform motion. d. The object has a non-zero acceleration during uniform motion.

The correct answer is: d. The object has a non-zero acceleration during uniform motion.

A ball is thrown straight up into the air. At the very top of the motion (at the maximum height), is the magnitude of the ball's acceleration greater than g, equal to g, less than g, or zero? Select one: a. greater than g b. equal to g c. less than g d. zero

The correct answer is: equal to g

A ball is thrown straight up into the air. Just after leaving your hand, is the magnitude of the ball's acceleration greater than g, equal to g, less than g, or zero? Select one: a. greater than g b. equal to g c. less than g d. zero

The correct answer is: equal to g

A ball is thrown straight up into the air. Just before hitting the ground, is the magnitude of the ball's acceleration greater than g, equal to g, less than g, or zero? Select one: a. greater than g b. equal to g c. less than g d. zero

The correct answer is: equal to g

A single particle has a mass, m, and it is at a distance, r, away from the origin. The moment of inertia of this particle about the origin is Select one: mr m2r m2r2 m2r4 mr2

The correct answer is: mr2

Circular motion is best analyzed in a coordinate system with Select one: x- and y-axes. x- and z-axes. r-, t-, and z-axes.

The correct answer is: r-, t-, and z-axes.

The change in speed in non-uniform circular motion is due to the Select one: a. the radial acceleration, or the perpendicular component of the particles acceleration vector b. the tangential acceleration, or the parallel component of the particles acceleration vector

The correct answer is: the tangential acceleration, or the parallel component of the particles acceleration vector

Suppose you press your physics book against a wall hard enough to keep it from moving. Which direction does the friction force on the book point? Select one: a. into the wall b. out of the wall c. up d. down e. there is no friction force

The correct answer is: up

A particular interaction force does work Wint inside a system. The potential energy of the interaction is U. Which equation relates U and Wint? Select one: U = Wint ΔU = Wint U = −Wint ΔU = −Wint

The correct answer is: ΔU = −Wint

You've just kicked a rock, and it is now sliding across the ground about 2 meters in front of you. Which of these forces act on the rock? Select all that apply. Select one or more: a. Gravity. acting downward. b. The normal force, acting upward. c. The force of the kick, acting in the direction of motion. d. Friction, acting opposite the direction of motion. e. Air resistance, acting opposite the direction of motion.

The correct answers are: Gravity. acting downward., The normal force, acting upward., Friction, acting opposite the direction of motion., Air resistance, acting opposite the direction of motion.

An object experiencing a constant force accelerates at 8.0 m/s2. What will the acceleration of this object be if the force is halved? Select one: a. 16 m/s2 b. 8.0 m/s2 c. 4.0 m/s2 d. 2.0 m/s2

a=F/m The correct answer is: 4.0 m/s2