Physics Semester Exam Review

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To describe the motion of a particle along a straight line, it is often convenient to draw a graph representing the position of the particle at different times. This type of graph is usually referred to as an x vs. t graph. To draw such a graph, choose an axis system in which time t is plotted on the horizontal axis and position x on the vertical axis. Then, indicate the values of x at various times t. Mathematically, this corresponds to plotting the variable x as a function of t. An example of a graph of position as a function of time for a particle traveling along a straight line is shown below. Note that an x vs. t graph like this does not represent the path of the particle in space. https://session.masteringphysics.com/problemAsset/1014243/21/1014243A.jpg What is the instantaneous velocity v of the particle at t=10.0s? Express your answer in meters per second.

0.600 m/s

A 3.0-kg mass and a 5.0-kg mass hang vertically at the opposite ends of a rope that goes over an ideal pulley. If the masses are gently released from rest, how long does it take for the 3.0-kg mass to rise by 1.0 m? 0.74 s 0.41 s 0.90 s 0.82 s 1.8 s

0.90 s

We set the origin of a coordinate system so that the position of a train is x = 0 m at t = 0 s. (Figure 1) shows the train's velocity graph. https://session.masteringphysics.com/problemAsset/1819583/4/jfk.Figure.02.U50EOC.jpg Find the acceleration of the train at t = 3.0 s. Express your answer to two significant figures and include the appropriate units.

1.0 m/s2

When jumping, a flea rapidly extends its legs, reaching a takeoff speed of 1.0 m/s over a distance of 0.50 mm . How long does it take the flea to leave the ground after it begins pushing off? Express your answer to two significant figures and include the appropriate units.

1.0×10−3 s

Three identical blocks connected by ideal strings are being pulled along a horizontal frictionless surface by a horizontal force F⃗ . (Figure 1)The magnitude of the tension in the string between blocks B and C is T = 3.00 N . Assume that each block has mass m = 0.400 kg . https://session.masteringphysics.com/problemAsset/1011159/17/9374.jpg What is the tension TAB in the string between block A and block B? Express your answer numerically in newtons

1.50 N

When jumping, a flea rapidly extends its legs, reaching a takeoff speed of 1.0 m/s over a distance of 0.50 mm . What is the flea's acceleration as it extends its legs? Express your answer to two significant figures and include the appropriate units.

1000 m/s2

A 55-kg box rests on a horizontal surface. The coefficient of static friction between the box and the surface is 0.30. A horizontal 140-N force is applied to the box. What is the friction force on the box? 42 N 0.00 N 140 N 16.5 N 160 N

140 N

A chair of weight 120 N lies atop a horizontal floor; the floor is not frictionless. You push on the chair with a force of F = 35.0 N directed at an angle of 41.0 ∘ below the horizontal and the chair slides along the floor. Using Newton's laws, calculate n, the magnitude of the normal force that the floor exerts on the chair. Express your answer in newtons.

143 N

https://session.masteringphysics.com/problemAsset/1810225/3/jfk.Figure.02.U47EOC.jpg Does this particle have a turning point or points? If so, at what time or times? If there is more than one answer, separate them by a comma.

2.00 s

The figure shows a block of mass m resting on a 20° slope. The block has coefficients of friction μs =0.64 and μk =0.64 with the surface of the slope. It is connected using a very light string over an ideal pulley to a hanging block of mass 2.0 kg. The string above the slope pulls parallel to the surface. What is the minimum mass m so the system will remain at rest when it is released from rest? https://session.masteringphysics.com/problemAsset/1901443/3/8514105041.jpg 3.6 kg 1.3 kg 3.3 kg 2.1 kg

2.1 kg

When a jet lands on an aircraft carrier, a hook on the tail of the plane grabs a wire that quickly brings the plane to a halt before it overshoots the deck. In a typical landing, a jet touching down at 240 km/h is stopped in a distance of 95 m . How much time does the landing take? Express your answer to two significant figures and include the appropriate units.

2.9 s

When a jet lands on an aircraft carrier, a hook on the tail of the plane grabs a wire that quickly brings the plane to a halt before it overshoots the deck. In a typical landing, a jet touching down at 240 km/h is stopped in a distance of 95 m . What is the magnitude of the jet's acceleration as it is brought to rest? Express your answer to two significant figures and include the appropriate units.

23 m/s2

The graph in the figure shows the position of a particle as it travels along the x-axis. https://session.masteringphysics.com/problemAsset/1901113/2/8514103010.jpg At what value of t is the speed of the particle equal to 0 m/s? 1 s 3 s 0 s 2 s 4 s

3 s

To describe the motion of a particle along a straight line, it is often convenient to draw a graph representing the position of the particle at different times. This type of graph is usually referred to as an x vs. t graph. To draw such a graph, choose an axis system in which time t is plotted on the horizontal axis and position x on the vertical axis. Then, indicate the values of x at various times t. Mathematically, this corresponds to plotting the variable x as a function of t. An example of a graph of position as a function of time for a particle traveling along a straight line is shown below. Note that an x vs. t graph like this does not represent the path of the particle in space. https://session.masteringphysics.com/problemAsset/1014243/21/1014243A.jpg What is the overall displacement Δx of the particle? Express your answer in meters.

30 m

https://session.masteringphysics.com/problemAsset/1014243/21/1014243BB.jpg Shown in the figure is the v vs. t curve selected in the previous part. What is the area A of the shaded region under the curve?(Figure 2) Express your answer in meters.

30 m

A person's reaction time is generally not quick enough to allow the person to catch a $1 bill dropped between the fingers. The 16 cm length of the bill passes through a student's fingers before she can grab it if she has 0.25 s reaction time. If a reaction time in this case is 0.25 s , how long would a bill need to be for her to have a good chance of catching it? Express your answer to two significant figures and include the appropriate units.

31 cm

A driver in a 1000-kg car traveling at 24 m/s slams on the brakes and skids to a stop. If the coefficient of friction between the tires and the level road is 0.80, how long will the skid marks be? 30 m 37 m 34 m 46 m

37 m

A 15-kg block is on a frictionless ramp that is inclined at 20° above the horizontal. It is connected by a very light string over an ideal pulley at the top edge of the ramp to a hanging 19-kg block, as shown in the figure. The string pulls on the 15-kg block parallel to the surface of the ramp. Find the magnitude of the acceleration of the 19-kg block after the system is gently released? https://session.masteringphysics.com/problemAsset/1901440/2/8514105039.jpg 3.8 m/s2 4.2 m/s2 4.5 m/s2 4.0 m/s2

4.0 m/s2

An airplane increases its speed at the average rate of 15 m/s2. How much time does it take to increase its speed from 100 m/s to 160 m/s? 0.058 s 4.0 s 17 s 0.25 s

4.0 s

In a 5.00 km race, one runner runs at a steady 11.7 km/h and another runs at 14.0 km/h . How long does the faster runner have to wait at the finish line to see the slower runner cross?

4.21 min

Three identical blocks connected by ideal strings are being pulled along a horizontal frictionless surface by a horizontal force F⃗ . (Figure 1)The magnitude of the tension in the string between blocks B and C is T = 3.00 N . Assume that each block has mass m = 0.400 kg . https://session.masteringphysics.com/problemAsset/1011159/17/9374.jpg What is the magnitude F of the force? Express your answer numerically in newtons.

4.50 N

A gymnast of mass 53.0 kg hangs from a vertical rope attached to the ceiling. You can ignore the weight of the rope and assume that the rope does not stretch. Use the value 9.81m/s2 for the acceleration of gravity. Calculate the tension T in the rope if the gymnast slides down the rope with a downward acceleration of magnitude 1.20 m/s2 . Express your answer in newtons.

456 N

A gymnast of mass 53.0 kg hangs from a vertical rope attached to the ceiling. You can ignore the weight of the rope and assume that the rope does not stretch. Use the value 9.81m/s2 for the acceleration of gravity. Calculate the tension T in the rope if the gymnast climbs the rope at a constant rate. Express your answer in newtons.

520 N

A gymnast of mass 53.0 kg hangs from a vertical rope attached to the ceiling. You can ignore the weight of the rope and assume that the rope does not stretch. Use the value 9.81m/s2 for the acceleration of gravity. Calculate the tension T in the rope if the gymnast hangs motionless on the rope. Express your answer in newtons.

520 N

A gymnast of mass 53.0 kg hangs from a vertical rope attached to the ceiling. You can ignore the weight of the rope and assume that the rope does not stretch. Use the value 9.81m/s2 for the acceleration of gravity. Calculate the tension T in the rope if the gymnast climbs up the rope with an upward acceleration of magnitude 1.20 m/s2 . Express your answer in newtons.

584 N

The motions described in each of the questions take place at an intersection on a two-lane road with a stop sign in each direction. For each motion, select the correct position versus time graph. For all of the motions, the stop sign is at the position x=0, and east is the positive x direction.(Figure 1) https://session.masteringphysics.com/problemAsset/1011353/17/1011353.jpg A driver ignores the stop sign and continues driving west at constant speed.

Two cars travel on the parallel lanes of a two-lane road. The cars' motions are represented by the position versus time graph shown in the figure. Answer the questions using the times from the graph indicated by letters. https://session.masteringphysics.com/problemAsset/1011348/26/1011348.jpg At which of the lettered times are the cars moving with nearly identical velocity?

We set the origin of a coordinate system so that the position of a train is x = 0 m at t = 0 s. (Figure 1) shows the train's velocity graph. https://session.masteringphysics.com/problemAsset/1819583/4/jfk.Figure.02.U50EOC.jpg Choose the correct position graph for the train. A:https://session.masteringphysics.com/problemAsset/1819583/4/jfk3.ch2.p20aa.jpg B:https://session.masteringphysics.com/problemAsset/1819583/4/jfk3.ch2.p20ac.jpg C:https://session.masteringphysics.com/problemAsset/1819583/4/jfk3.ch2.p20ad.jpg D:https://session.masteringphysics.com/problemAsset/1819583/4/jfk3.ch2.p20ab.jpg

A racing car accelerates uniformly from rest along a straight track. This track has markers spaced at equal distances along it from the start, as shown in the figure. The car reaches a speed of 140 km/h as it passes marker 2. https://session.masteringphysics.com/problemAsset/1901085/2/8514103001.jpg Where on the track was the car when it was traveling at half this speed, that is at 70 km/h? Before marker 1 At marker 1 Between marker 1 and marker 2

Before marker 1

In the situation shown in the figure, a person is pulling with a constant, nonzero force F⃗ on string 1, which is attached to block A. Block A is also attached to block B via string 2, as shown. For this problem, assume that neither string stretches and that friction is negligible. Both blocks have finite (nonzero) mass. (Figure 1) https://session.masteringphysics.com/problemAsset/1010966/21/MLD_1d_2_a.jpg Which one of the following statements correctly descibes the relationship between the accelerations of blocks A and B? Block A has a larger acceleration than block B. Block B has a larger acceleration than block A. Both blocks have the same acceleration. More information is needed to determine the relationship between the accelerations.

Both blocks have the same acceleration.

During an experiment, a crate is pulled along a rough horizontal surface by a force F⃗ and the magnitude of the acceleration along the x direction, ax, is measured.(Figure 1) The vector F⃗ has a component along the x direction of magnitude Fx. The experiment is repeated several times, with different values of Fx each time, while maintaining a constant value for, Fy, the vertical component of F⃗ . After all the trials are completed, a graph of acceleration ax as a function of force Fx is plotted. Assuming the presence of both static and kinetic friction, which of the following graphs (Figure 4) is most nearly correct? https://session.masteringphysics.com/problemAsset/1011642/33/1011642B.jpg A B C D

We set the origin of a coordinate system so that the position of a train is x = 0 m at t = 0 s. (Figure 1) shows the train's velocity graph. https://session.masteringphysics.com/problemAsset/1819583/4/jfk.Figure.02.U50EOC.jpg Choose the correct acceleration graph for the train. A:https://session.masteringphysics.com/problemAsset/1819583/4/jfk3.ch2.p20bd.jpg B:https://session.masteringphysics.com/problemAsset/1819583/4/jfk3.ch2.p20bc.jpg C:https://session.masteringphysics.com/problemAsset/1819583/4/jfk3.ch2.p20ba.jpg D:https://session.masteringphysics.com/problemAsset/1819583/4/jfk3.ch2.p20bb.jpg

:https://session.masteringphysics.com/problemAsset/1819582/4/jfk.Figure.02.U49EOC.jpg Choose the correct bicycle's acceleration graph for the interval 0s≤t≤4s. A:https://session.masteringphysics.com/problemAsset/1819582/4/jfk3.ch2.p19c.jpg B:https://session.masteringphysics.com/problemAsset/1819582/4/jfk3.ch2.p19b.jpg C:https://session.masteringphysics.com/problemAsset/1819582/4/jfk3.ch2.p19d.jpg D:https://session.masteringphysics.com/problemAsset/1819582/4/jfk3.ch2.p19a.jpg

During an experiment, a crate is pulled along a rough horizontal surface by a force F⃗ and the magnitude of the acceleration along the x direction, ax, is measured.(Figure 1) The vector F⃗ has a component along the x direction of magnitude Fx. The experiment is repeated several times, with different values of Fx each time, while maintaining a constant value for, Fy, the vertical component of F⃗ . Create a plot of the force of kinetic friction, fk, versus the x component of the pulling force, Fx, for the experiment. Let the point Fmin, along the horizontal axis, represent the minimum force required to accelerate the crate. Choose the graph that most accurately depicts the relationship among fk, Fx, and Fmin. (Figure 3) https://session.masteringphysics.com/problemAsset/1011642/33/1011642D.jpg A B C D

During an experiment, a crate is pulled along a rough horizontal surface by a force F⃗ and the magnitude of the acceleration along the x direction, ax, is measured.(Figure 1) The vector F⃗ has a component along the x direction of magnitude Fx. The experiment is repeated several times, with different values of Fx each time, while maintaining a constant value for, Fy, the vertical component of F⃗ . Create a plot of the force of static friction, fs, versus the x component of the pulling force, Fx, for the experiment. Let the point Fmin, along the horizontal axis, represent the minimum force required to accelerate the crate. Choose the graph that most accurately depicts the relationship among fs, Fx, and Fmin. (Figure 2) https://session.masteringphysics.com/problemAsset/1011642/33/1011642C.jpg A B C D E

The motions described in each of the questions take place at an intersection on a two-lane road with a stop sign in each direction. For each motion, select the correct position versus time graph. For all of the motions, the stop sign is at the position x=0, and east is the positive x direction.(Figure 1) https://session.masteringphysics.com/problemAsset/1011353/17/1011353.jpg A driver, after stopping at the stop sign, travels east with a positive acceleration.

The motions described in each of the questions take place at an intersection on a two-lane road with a stop sign in each direction. For each motion, select the correct position versus time graph. For all of the motions, the stop sign is at the position x=0, and east is the positive x direction.(Figure 1) https://session.masteringphysics.com/problemAsset/1011353/17/1011353.jpg A driver, traveling west, slows and stops at the stop sign.

Another common graphical representation of motion along a straight line is the v vs. t graph, that is, the graph of (instantaneous) velocity as a function of time. In this graph, time t is plotted on the horizontal axis and velocity v on the vertical axis. Note that by definition, velocity and acceleration are vector quantities. In straight-line motion, however, these vectors have only one nonzero component in the direction of motion. Thus, in this problem, we will call v the velocity and a the acceleration, even though they are really the components of the velocity and acceleration vectors in the direction of motion. Which of the graphs shown is the correct v vs. t plot for the motion described in the previous parts? https://session.masteringphysics.com/problemAsset/1014243/21/1014243BB.jpg

Graph D

https://session.masteringphysics.com/problemAsset/1810225/3/jfk.Figure.02.U47EOC.jpg Determine the particle's velocity for the each of the following intervals: 0s≤t≤1s, 1s≤t≤2s, 2s≤t≤4s . Express your answers in the indicated order using two significant figures separated by commas.

0,20,-10 m/s

During a hockey game, a puck is given an initial speed of 10 m/s. It slides 50 m on the horizontal ice before it stops due to friction. What is the coefficient of kinetic friction between the puck and the ice? 0.090 0.10 0.11 0.12

0.10

A 50.0-kg crate is being pulled along a horizontal smooth surface. The pulling force is 10.0 N and is directed 20.0° above the horizontal. What is the magnitude of the acceleration of the crate? 0.0684 m/s2 0.200 m/s2 0.0728 m/s2 0.188 m/s2 0.376 m/s2

0.188 m/s2

A car is traveling north at 17.7 m/s After 12 s its velocity is 14.1 m/s in the same direction. Find the magnitude and direction of the car's average acceleration. 0.30 m/s2, north 2.7 m/s2, north 0.30 m/s2, south 2.7 m/s2, south

0.30 m/s2, south

To describe the motion of a particle along a straight line, it is often convenient to draw a graph representing the position of the particle at different times. This type of graph is usually referred to as an x vs. t graph. To draw such a graph, choose an axis system in which time t is plotted on the horizontal axis and position x on the vertical axis. Then, indicate the values of x at various times t. Mathematically, this corresponds to plotting the variable x as a function of t. An example of a graph of position as a function of time for a particle traveling along a straight line is shown below. Note that an x vs. t graph like this does not represent the path of the particle in space. https://session.masteringphysics.com/problemAsset/1014243/21/1014243A.jpg What is the average velocity Vav of the particle over the time interval Δt=50.0s ? Express your answer in meters per second.

0.600 m/s

A ball is thrown downward in the absence of air resistance. After it has been released, which statement(s) concerning its acceleration is correct? (There could be more than one correct choice.) Its acceleration is greater than g. Its acceleration is zero. Its acceleration is constantly decreasing. Its acceleration is constantly increasing. Its acceleration is constant.

Its acceleration is constant.

A ball is thrown straight up, reaches a maximum height, then falls to its initial height. Which of the following statements about the direction of the velocity and acceleration of the ball as it is going up is correct? Both its velocity and its acceleration point upward. Its velocity points upward and its acceleration points downward. Its velocity points downward and its acceleration points upward. Both its velocity and its acceleration points downward.

Its velocity points upward and its acceleration points downward.

To clarify the distinction between speed and velocity, and to review qualitatively one-dimensional kinematics. A woman stands at the edge of a cliff, holding one ball in each hand. At time t0, she throws one ball straight up with speed v0 and the other straight down, also with speed v0. For the following questions neglect air resistance. Pay particular attention to whether the answer involves "absolute" quantities that have only magnitude (e.g., speed) or quantities that can have either sign (e.g., velocity). Take upward to be the positive direction. Which ball has the greater acceleration at the instant of release? the ball thrown upward the ball thrown downward Neither; the accelerations of both balls are the same.

Neither; the accelerations of both balls are the same.

To clarify the distinction between speed and velocity, and to review qualitatively one-dimensional kinematics. A woman stands at the edge of a cliff, holding one ball in each hand. At time t0, she throws one ball straight up with speed v0 and the other straight down, also with speed v0. For the following questions neglect air resistance. Pay particular attention to whether the answer involves "absolute" quantities that have only magnitude (e.g., speed) or quantities that can have either sign (e.g., velocity). Take upward to be the positive direction. Which ball hits the ground with greater speed? the ball thrown upward the ball thrown downward Neither; the balls hit the ground with the same speed.

Neither; the balls hit the ground with the same speed.

To clarify the distinction between speed and velocity, and to review qualitatively one-dimensional kinematics. A woman stands at the edge of a cliff, holding one ball in each hand. At time t0, she throws one ball straight up with speed v0 and the other straight down, also with speed v0. For the following questions neglect air resistance. Pay particular attention to whether the answer involves "absolute" quantities that have only magnitude (e.g., speed) or quantities that can have either sign (e.g., velocity). Take upward to be the positive direction. Which ball has the greater speed at the instant of release? the ball thrown upward the ball thrown downward Neither; the speeds are the same.

Neither; the speeds are the same.

A push of magnitude P acts on a box of weight W as shown in the figure. The push is directed at an angle θ below the horizontal, and the box remains a rest. The box rests on a horizontal surface that has some friction with the box. The friction force on the box due to the floor is equal to https://session.masteringphysics.com/problemAsset/1901391/3/8514105012.jpg Pcos(θ) Psin(θ) Pcos(θ)+W 0 P+W

Pcos(θ)

Identify the following physical quantities as scalars or vectors. Position Velocity Displacement Speed Acceleration Average Velocity Distance

Scalar: Speed Distance Vector: Position Velocity Displacement Acceleration Average Velocity

A 10-kg rock and 20-kg rock are dropped from the same height and experience no significant air resistance. If it takes the 20-kg rock a time T to reach the ground, what time will it take the 10-kg rock to reach the ground? T/4 2T T4 T T/2

In the situation shown in the figure, a person is pulling with a constant, nonzero force F⃗ on string 1, which is attached to block A. Block A is also attached to block B via string 2, as shown. For this problem, assume that neither string stretches and that friction is negligible. Both blocks have finite (nonzero) mass. (Figure 1) https://session.masteringphysics.com/problemAsset/1010966/21/MLD_1d_2_a.jpg How does the magnitude of the tension in string 1, T1, compare with the tension in string 2, T2? T1>T2 T1=T2 T1<T2 More information is needed to determine the relationship between T1 and T2.

T1>T2

A rock from a volcanic eruption is launched straight up into the air with no appreciable air resistance. Which one of the following statements about this rock while it is in the air is correct? -On the way down, both its velocity and acceleration are downward, and at the highest point both its velocity and acceleration are zero. -The acceleration is downward at all points in the motion except that is zero at the highest point. -The acceleration is downward at all points in the motion. -On the way up, its acceleration is downward and its velocity is upward, and at the highest point both its velocity and acceleration are zero. -Throughout the motion, the acceleration is downward, and the velocity is always in the same direction as the acceleration.

The acceleration is downward at all points in the motion.

To introduce contact forces: the normal force and the force due to friction.. Two types of contact forces operate in typical mechanics problems: the normal force (usually designated by n⃗ ) and frictional forces (designated by f⃗ ). The normal force is always perpendicular to the plane of contact, whereas the force due to friction is parallel to the plane of contact. When two surfaces slide against each other, experiments show three things about the resulting kinetic frictional force f⃗ k: The frictional force opposes the relative motion of the two surfaces at their point of contact. The magnitude of the kinetic frictional force, fk, is proportional to the magnitude of the normal force, n. The ratio of fk to n is fairly constant over a wide range of speeds. The constant of proportionality is called the coefficient of kinetic friction and is often designated μk. As long as the sliding continues, the frictional force is fk=μkn. When there is no relative motion of the two surfaces, the magnitude of the static frictional force can assume any value from zero up to a maximum μsn, where μs is known as the coefficient of static friction; μs is, invariably, larger than μk. The frictional force for surfaces that do not move relative to each other is therefore fs≤μsn. The equality fs=μsn holds only when the surfaces are on the verge of sliding. When two objects slide against one another, which of the following statements about the force of friction between them is true? The magnitude of the frictional force is always equal to μkn. The magnitude of the frictional force is always less than μkn. The magnitude of the frictional force is determined by other forces on the objects so it can be either equal to or less than μkn.

The magnitude of the frictional force is always equal to μkn.

Two objects are thrown from the top of a tall building. One is thrown up, and the other is thrown down, both with the same initial speed. What are their speeds when they hit the street? Neglect air resistance. The one thrown up is traveling faster. The one thrown down is traveling faster. They are traveling at the same speed. It is impossible to tell because the height of the building is not given.

They are traveling at the same speed.

A 10-kg rock and a 20-kg rock are dropped at the same time and experience no significant air resistance. If the 10-kg rock falls with acceleration a, what is the acceleration of the 20-kg rock? a/4 4a a a/2 2a

An object is moving with constant non-zero velocity in the +x direction. The velocity versus time graph of this object is a horizontal straight line. a vertical straight line. a straight line making an angle with the time axis. a parabolic curve.

a horizontal straight line

An object is moving with constant non-zero acceleration in the +x direction. The position versus time graph of this object is a horizontal straight line. a vertical straight line. a straight line making an angle with the time axis. a parabolic curve.

a parabolic curve

An object is moving with constant non-zero velocity in the +x direction. The position versus time graph of this object is a horizontal straight line. a vertical straight line. a straight line making an angle with the time axis. a parabolic curve.

a straight line making an angle with the time axis

To clarify the distinction between speed and velocity, and to review qualitatively one-dimensional kinematics. A woman stands at the edge of a cliff, holding one ball in each hand. At time t0, she throws one ball straight up with speed v0 and the other straight down, also with speed v0. For the following questions neglect air resistance. Pay particular attention to whether the answer involves "absolute" quantities that have only magnitude (e.g., speed) or quantities that can have either sign (e.g., velocity). Take upward to be the positive direction. If the ball that is thrown downward has an acceleration of magnitude a at the instant of its release (i.e., when there is no longer any force on the ball due to the woman's hand), what is the relationship between a and g, the magnitude of the acceleration of gravity? a>g a=g a<g

a=g

A 6-kg bucket of water is being pulled straight up by a string at a constant speed. Now assume that the bucket has a downward acceleration, with a constant acceleration of magnitude 3 m/s2. What is the tension in the rope? about 42 N about 60 N about 78 N It is decreasing as the speed increases.

about 42 N

A 6-kg bucket of water is being pulled straight up by a string at a constant speed. What is the tension in the rope? about 42 N about 60 N about 78 N 0 N because the bucket has no acceleration.

about 60 N

A 6-kg bucket of water is being pulled straight up by a string at a constant speed. At a certain point the speed of the bucket begins to change. The bucket now has an upward constant acceleration of magnitude 3 m/s2. What is the tension in the rope now? about 42 N about 60 N about 78 N It is increasing as the speed increases.

about 78 N

The slope of a velocity versus time graph gives acceleration. displacement. the distance traveled. velocity.

acceleration

If the position versus time graph of an object is a horizontal line, the object is moving with constant non-zero speed. moving with constant non-zero acceleration. at rest. moving with increasing speed.

at rest

Two forces, of magnitude 4N and 10N, are applied to an object. The relative direction of the forces is unknown. The net force acting on the object __________. Check all that apply. cannot have a magnitude equal to 5N cannot have a magnitude equal to 10N cannot have the same direction as the force with magnitude 10N must have a magnitude greater than 10N

cannot have a magnitude equal to 5N

components

direction

The area under a curve in a velocity versus time graph gives displacement. position. velocity. acceleration.

displacement

distance

Two blocks are stacked on top of each other on the floor of an elevator. For each of the following situations, select the correct relationship between the magnitudes of the two forces given.(Figure 1) You will be asked two questions about each of three situations. Each situation is described above the first in the pair of questions. Do not assume anything about a given situation except for what is given in the description for that particular situation. https://session.masteringphysics.com/problemAsset/1013359/13/1013359.jpg The elevator is moving downward at a constant speed. The magnitude of the force of the bottom block on the top block is _____________ the magnitude of the force of the earth on the top block. greater than equal to less than unknown compared to

equal to

Two blocks are stacked on top of each other on the floor of an elevator. For each of the following situations, select the correct relationship between the magnitudes of the two forces given.(Figure 1) You will be asked two questions about each of three situations. Each situation is described above the first in the pair of questions. Do not assume anything about a given situation except for what is given in the description for that particular situation. https://session.masteringphysics.com/problemAsset/1013359/13/1013359.jpg The elevator is moving downward at a constant speed. The magnitude of the force of the bottom block on top block is _______ the magnitude of the force of the top block on bottom block. greater than equal to less than unknown compared to

equal to

Two blocks are stacked on top of each other on the floor of an elevator. For each of the following situations, select the correct relationship between the magnitudes of the two forces given.(Figure 1) You will be asked two questions about each of three situations. Each situation is described above the first in the pair of questions. Do not assume anything about a given situation except for what is given in the description for that particular situation. https://session.masteringphysics.com/problemAsset/1013359/13/1013359.jpg The elevator is moving downward at an increasing speed. The magnitude of the force of the bottom block on the top block is ________ the magnitude of the force of the top block on the bottom block. greater than equal to less than unknown compared to

equal to

Two blocks are stacked on top of each other on the floor of an elevator. For each of the following situations, select the correct relationship between the magnitudes of the two forces given.(Figure 1) You will be asked two questions about each of three situations. Each situation is described above the first in the pair of questions. Do not assume anything about a given situation except for what is given in the description for that particular situation. https://session.masteringphysics.com/problemAsset/1013359/13/1013359.jpg The elevator is moving upward. The magnitude of the force of the bottom block on the top block is ________ the magnitude of the force of the top block on the bottom block. greater than equal to less than unknown compared to

equal to

In the figure, what does the spring scale read? The pulleys are ideal and the strings and scale are also massless. https://session.masteringphysics.com/problemAsset/1901392/3/8514105013.jpg more than 19.6 N exactly 2.0 N exactly 1.0 N 0.50 N 0.00 N

exactly 1.0 N

A block of mass m sits at rest on a rough inclined ramp that makes an angle θ with the horizontal. What must be true about force of static friction f on the block? f> mgcos(θ) f > mg f = mgsin(θ) f = mgcos(θ) f > mgsin(θ)

f = mgsin(θ)

A 10-kg rock and a 20-kg rock are thrown upward with the same initial speed v0 and experience no significant air resistance. If the 10-kg rock reaches a maximum height h, what maximum height will the 20-kg ball reach? h/2 h h/4 2h 4h

When a ball is thrown straight up with no air resistance, the acceleration at its highest point is zero is downward is upward reverses from downward to upward reverses from upward to downward

is downward

Two blocks are stacked on top of each other on the floor of an elevator. For each of the following situations, select the correct relationship between the magnitudes of the two forces given.(Figure 1) You will be asked two questions about each of three situations. Each situation is described above the first in the pair of questions. Do not assume anything about a given situation except for what is given in the description for that particular situation. https://session.masteringphysics.com/problemAsset/1013359/13/1013359.jpg The elevator is moving downward at an increasing speed. The magnitude of the force of the bottom block on the top block is _______ the magnitude of the force of the earth on the top block. greater than equal to less than unknown compared to

less than

magnitude

A massive block is being pulled along a horizontal frictionless surface by a constant horizontal force. The block must be __________. continuously changing direction moving at constant velocity moving with a constant nonzero acceleration moving with continuously increasing acceleration

moving with a constant nonzero acceleration

If the velocity versus time graph of an object is a horizontal line, the object is moving with zero acceleration. moving with constant non-zero acceleration. at rest. moving with increasing speed.

moving with zero acceleration

Two cars travel on the parallel lanes of a two-lane road. The cars' motions are represented by the position versus time graph shown in the figure. Answer the questions using the times from the graph indicated by letters. https://session.masteringphysics.com/problemAsset/1011348/26/1011348.jpg Are the two cars traveling in the same direction when they pass each other?

none

To clarify the distinction between speed and velocity, and to review qualitatively one-dimensional kinematics. A woman stands at the edge of a cliff, holding one ball in each hand. At time t0, she throws one ball straight up with speed v0 and the other straight down, also with speed v0. For the following questions neglect air resistance. Pay particular attention to whether the answer involves "absolute" quantities that have only magnitude (e.g., speed) or quantities that can have either sign (e.g., velocity). Take upward to be the positive direction. Which ball has the greater average speed during the 1-s interval after release (assuming neither hits the ground during that time)? the ball thrown upward the ball thrown downward Neither; the average speeds of both balls are the same.

the ball thrown downward

From the edge of a roof top you toss a green ball upwards with initial speed v0 and a blue ball downwards with the same initial speed. Air resistance is negligible. When they reach the ground below the blue ball will be moving faster than the green ball. the green ball will be moving faster than the blue ball. the two balls will have the same speed.

the two balls will have the same speed

Two blocks are stacked on top of each other on the floor of an elevator. For each of the following situations, select the correct relationship between the magnitudes of the two forces given.(Figure 1) You will be asked two questions about each of three situations. Each situation is described above the first in the pair of questions. Do not assume anything about a given situation except for what is given in the description for that particular situation. https://session.masteringphysics.com/problemAsset/1013359/13/1013359.jpg The elevator is moving upward. The magnitude of the force of the bottom block on the top block is _______ the magnitude of the force of the earth on the top block. greater than equal to less than unknown compared to

unknown compared to

vector

The slope of a position versus time graph gives displacement. velocity. acceleration. the distance traveled.

velocity

A block of mass 2kg is acted upon by two forces: 3N (directed to the left) and 4N (directed to the right). What can you say about the block's motion? It must be moving to the left. It must be moving to the right. It must be at rest. It could be moving to the left, moving to the right, or be instantaneously at rest.

It could be moving to the left, moving to the right, or be instantaneously at rest.

To introduce contact forces: the normal force and the force due to friction.. Two types of contact forces operate in typical mechanics problems: the normal force (usually designated by n⃗ ) and frictional forces (designated by f⃗ ). The normal force is always perpendicular to the plane of contact, whereas the force due to friction is parallel to the plane of contact. When two surfaces slide against each other, experiments show three things about the resulting kinetic frictional force f⃗ k: The frictional force opposes the relative motion of the two surfaces at their point of contact. The magnitude of the kinetic frictional force, fk, is proportional to the magnitude of the normal force, n. The ratio of fk to n is fairly constant over a wide range of speeds. The constant of proportionality is called the coefficient of kinetic friction and is often designated μk. As long as the sliding continues, the frictional force is fk=μkn. When there is no relative motion of the two surfaces, the magnitude of the static frictional force can assume any value from zero up to a maximum μsn, where μs is known as the coefficient of static friction; μs is, invariably, larger than μk. The frictional force for surfaces that do not move relative to each other is therefore fs≤μsn. The equality fs=μsn holds only when the surfaces are on the verge of sliding. When a board with a box on it is slowly tilted to a larger and larger angle, common experience shows that the box will at some point "break loose" and start to accelerate down the board. The box begins to slide once the component of its weight parallel to the board, w||, equals the maximum force of static friction. Which of the following is the most general explanation for why the box accelerates down the board after it begins to slide (rather than sliding with constant speed)? When the box is stationary, w|| equals the force of static friction, but once the box starts moving, the sliding reduces the normal force, which in turn reduces the friction. Once the box is moving, w|| is less than the force of static friction but greater than the force of kinetic friction. The coefficient of kinetic friction is less than the coefficient of static friction. Once the box is moving, w|| is greater than the force of static friction but less than the force of kinetic friction.

The coefficient of kinetic friction is less than the coefficient of static friction.

To introduce contact forces: the normal force and the force due to friction.. Two types of contact forces operate in typical mechanics problems: the normal force (usually designated by n⃗ ) and frictional forces (designated by f⃗ ). The normal force is always perpendicular to the plane of contact, whereas the force due to friction is parallel to the plane of contact. When two surfaces slide against each other, experiments show three things about the resulting kinetic frictional force f⃗ k: The frictional force opposes the relative motion of the two surfaces at their point of contact. The magnitude of the kinetic frictional force, fk, is proportional to the magnitude of the normal force, n. The ratio of fk to n is fairly constant over a wide range of speeds. The constant of proportionality is called the coefficient of kinetic friction and is often designated μk. As long as the sliding continues, the frictional force is fk=μkn. When there is no relative motion of the two surfaces, the magnitude of the static frictional force can assume any value from zero up to a maximum μsn, where μs is known as the coefficient of static friction; μs is, invariably, larger than μk. The frictional force for surfaces that do not move relative to each other is therefore fs≤μsn. The equality fs=μsn holds only when the surfaces are on the verge of sliding. When two objects are in contact with no relative motion, which of the following statements about the frictional force between them is true? The magnitude of the frictional force is always equal to μsn. The magnitude of the frictional force is always less than μsn. The magnitude of the frictional force may be either equal to or less than μsn.

The magnitude of the frictional force may be either equal to or less than μsn.

When an object rests on a surface, there is always a force perpendicular to the surface; we call this the normal force, denoted by n⃗ . The two questions to the right will explore the normal force. https://session.masteringphysics.com/problemAsset/1011666/17/1011666A.jpg A man attempts to pick up his suitcase of weight ws by pulling straight up on the handle.(Figure 1) However, he is unable to lift the suitcase from the floor. Which statement about the magnitude of the normal force n acting on the suitcase is true during the time that the man pulls upward on the suitcase? -The magnitude of the normal force is equal to the magnitude of the weight of the suitcase. -The magnitude of the normal force is equal to the magnitude of the weight of the suitcase minus the magnitude of the force of the pull. -The magnitude of the normal force is equal to the sum of the magnitude of the force of the pull and the magnitude of the suitcase's weight. -The magnitude of the normal force is greater than the magnitude of the weight of the suitcase.

The magnitude of the normal force is equal to the magnitude of the weight of the suitcase minus the magnitude of the force of the pull.

When an object rests on a surface, there is always a force perpendicular to the surface; we call this the normal force, denoted by n⃗ . The two questions to the right will explore the normal force. https://session.masteringphysics.com/problemAsset/1011666/17/1011666C.jpg Now assume that the man of weight wm is tired and decides to sit on his suitcase.(Figure 2) Which statement about the magnitude of the normal force n acting on the suitcase is true during the time that the man is sitting on the suitcase? -The magnitude of the normal force is equal to the magnitude of the suitcase's weight. -The magnitude of the normal force is equal to the magnitude of the suitcase's weight minus the magnitude of the man's weight. -The magnitude of the normal force is equal to the sum of the magnitude of the man's weight and the magnitude of the suitcase's weight. -The magnitude of the normal force is less than the magnitude of the suitcase's weight.

The magnitude of the normal force is equal to the sum of the magnitude of the man's weight and the magnitude of the suitcase's weight.

An object at rest cannot remain at rest unless which of the following holds? The net force acting on it is zero. The net force acting on it is constant and nonzero. There are no forces at all acting on it. There is only one force acting on it.

The net force acting on it is zero.

If a block is moving to the left at a constant velocity, what can one conclude? There is exactly one force applied to the block. The net force applied to the block is directed to the left. The net force applied to the block is zero. There must be no forces at all applied to the block.

The net force applied to the block is zero.

One of the difficulties in studying mechanics is that many common words are used with highly specific technical meanings, among them velocity, acceleration, position, speed, and displacement. The series of questions in this problem is designed to get you to try to think of these quantities like a physicist. Answer the questions in this problem using words from the following list: position direction displacement coordinates velocity acceleration distance magnitude vector scalar components Consider a physical situation in which a particle moves from point A to point B. This process is described from two coordinate systems that are identical except that they have different origins. The __________ of the particle at point A differ(s) as expressed in one coordinate system compared to the other, but the __________ from A to B is/are the same as expressed in both coordinate systems. Type the letters from the list given in the problem introduction that best complete the sentence. Separate the letters with commas. There is more than one correct answer, but you should only enter one pair of comma-separated letters. For example, if the words "vector" and "scalar" fit best in the blanks, enter I,J.

position, displacement

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