Physics Study Guide AHHHHH

A moon orbits a planet in a nearly circular orbit of radius RR, as shown in the figure. Astronomers making careful observations of the moon's orbit discover that the orbit is not perfectly circular, nor is it elliptical. Which of the following statements supports this observation? The moon and the planet exert forces of equal magnitude on each other. Answer A: The moon and the planet exert forces of equal magnitude on each other. A There is another celestial body that exerts a gravitational force on the moon. Answer B: There is another celestial body that exerts a gravitational force on the moon. B The value of the gravitational constant GG is different in the location near the planet-moon system. Answer C: The value of the gravitational constant G is different in the location near the planet-moon system. C There is a centripetal force that causes the net force exerted on the moon to be different from the gravitational force.

There is another celestial body that exerts a gravitational force on the moon. Answer B: There is another celestial body that exerts a gravitational force on the moon.

A moon orbits a planet in a nearly circular orbit of radius RR, as shown in the figure. The moon has a mass of 1×1022 kg1×1022 kg, and the gravitational field strength at a distance RR from the planet is 0.001 N/kg0.001 N/kg. What is the gravitational force exerted on the moon while it is in orbit around the planet? 0 N0 N Answer A: 0 newtons A 1×1019 N1×1019 N Answer B: 1 times 10 to the power of 19 newtons B 1×1022 N1×1022 N Answer C: 1 times 10 to the power of 22 newtons C 1×1025 N

1×1019 N1×1019 N Answer B: 1 times 10 to the power of 19 newtons B

A moon of mass 1×1020 kg is in a circular orbit around a planet. The planet exerts a gravitational force of 2×1021 N on the moon. The centripetal acceleration of the moon is most nearly 0.05 ms2 Answer A: 0.05 meters per second squared A 10 ms2 Answer B: 10 meters per second squared B 20 ms2 Answer C: 20 meters per second squared C 2×10 41ms2

20 ms2 Answer C: 20 meters per second squared C

Two containers of water can have their individual masses varied by adding or removing water. The containers are initially a distance dd apart, as measured from their centers, and are filled with water so that each has a mass MM, as shown in Figure 1 above. The gravitational force that one container exerts on the other is F0F0. Water is then added to one container so that its mass increases to 1.5M1.5M, and water is removed from the other container so that its mass decreases to 0.5M0.5M, as shown in Figure 2. What is the new gravitational force exerted on one container by the other? 34F034F0 Answer A: three fourths F sub 0 A F0F0 Answer B: F sub 0 B 32F032F0 Answer C: three halves F sub 0 C 2F0

34F034F0 Answer A: three fourths F sub 0 A

Car XX and car YY travel on a horizontal surface along different parallel, straight paths. Each car's velocity as a function of time is shown in the graph. Which of the following claims is correct about car XX and car YY? A Both car XX and car YY travel in the same direction. B Between t=6 st=6 s and t=7 st=7 s, car XX and car YY are at the same horizontal position. C The change in car XX's speed per unit of time increases as the time increases, and the change in car YY's speed per unit of time decreases as the time increases. D The magnitude of the acceleration of car XX is the same as the magnitude of the acceleration of car YY.

A Both car XX and car YY travel in the same direction.

A toy car has a battery-powered fan attached to it such that the fan creates a constant force that is exerted on the car so that it is propelled in the opposite direction in which the fan blows air. The car has a carriage that allows a student to attach objects of different masses, as shown above. The fan has only one speed setting. All frictional forces are considered to be negligible. Which of the following procedures could be used to determine how the mass of the fan-car-object system affects the acceleration of the system? A Measure the mass of the system using a balance, activate the fan, measure the distance traveled by the system at a known time by using a stopwatch, and repeat the experiment for several trials with different objects added to the carriage. B Measure the mass of the system using a balance, activate the fan, use a meterstick and stopwatch to measure the initial and final speeds of the system, and repeat the experiment for several trials with different objects added to the carriage. C Measure the mass of the system using a balance, connect a spring scale to the back of the car, measure the amount of force required to hold the system at rest, and repeat the experiment for several trials with different objects added to the carriage. D Measure the mass of the system using a balance, activate the fan, use a stopwatch to record the time it takes for the system to travel before the battery of the fan no longer works, and repeat the experiment for several trials with different objects added to the carriage.

A Measure the mass of the system using a balance, activate the fan, measure the distance traveled by the system at a known time by using a stopwatch, and repeat the experiment for several trials with different objects added to the carriage.

A student must determine the inertial mass of a block attached to a horizontal track. The block is free to move horizontally along the track, as shown above. Frictional forces are considered to be negligible. The student may only choose two measuring tools to determine the inertial mass of the block. What tools should the student choose? Select two answers. Stopwatch Answer A: Stopwatch A Accelerometer Answer B: Accelerometer B Force sensor Answer C: Force sensor C Meterstick

Accelerometer Answer B: Accelerometer B Force sensor

An object is at rest on the ground. The object experiences a downward gravitational force from Earth. Which of the following predictions is correct about why the object does not accelerate downward? Select two answers. Justify your selections. A The bonded molecules of the object are repelled upward by the bonded molecules of the ground with the same magnitude as the gravitational force downward on the object. B The normal force is exerted upward on the object from the ground with the same magnitude as the gravitational force downward on the object. C The bonded molecules of the object are attracted downward by the bonded molecules of the ground with the same magnitude as the gravitational force downward on the object. D The force of friction is exerted upward on the object from the ground with the same magnitude as the gravitational force downward on the object.

A The bonded molecules of the object are repelled upward by the bonded molecules of the ground with the same magnitude as the gravitational force downward on the object. B The normal force is exerted upward on the object from the ground with the same magnitude as the gravitational force downward on the object.

A student sets up an experiment to determine the inertial mass of a cart. The student has access to the following measurement equipment: a spring scale, a meterstick, and a stopwatch. The student uses the spring scale to pull the cart starting from rest along a horizontal surface such that the reading on the spring scale is always constant. All frictional forces are negligible. In addition to the spring-scale reading, which two of the following quantities could the student measure with the available equipment and then use to determine the inertial mass of the cart? Select two answers. A The total distance traveled by the cart after it has been in motion B The average speed of the cart while in motion C The acceleration of the cart while in motion D The time during which the cart is in motion

A The total distance traveled by the cart after it has been in motion D The time during which the cart is in motion

Two objects, object XX and object YY, are held together by a light string and are released from rest near a planet's surface in the orientation that is shown in the figure. Object XX has a greater mass than object YY. A graph of the acceleration as a function of time for the system's center of mass is shown for the 4s4s. The positive direction is considered to be upward. How does the speed of object XX vxvx compare to that of the system's speed vsvs after the objects have fallen for 4s4s ? A vx=vsvx=vs B vx>vsvx>vs C vx<vsvx<vs D The answer cannot be determined without knowing the relative masses of object XX and object YY.

A vx=vsvx=vs

An object is held at an unknown height above Earth's surface, where the acceleration due to gravity of the object is considered to be constant. After the object is released from rest, a student must determine the object's speed the instant the object makes contact with the ground. Which of the following equations could the student use to determine the object's speed by using the fewest measuring tools if the student does not have access to a motion sensor? Select two answers. A vx=vx0+axtvx=vx0+axt B x=x0+vx0t+12axt2x=x0+vx0t+12axt2 C v2x=v2x0+2ax(x−x0)vx2=vx02+2ax(x−x0) D v¯=x−x0t

A vx=vx0+axtvx=vx0+axt C v2x=v2x0+2ax(x−x0)vx2=vx02+2ax(x−x0)

Toy car WW travels across a horizontal surface with an acceleration of awaw after starting from rest. Toy car ZZ travels across the same surface toward car WW with an acceleration of azaz after starting from rest. Car WW is separated from car ZZ by a distance dd. Which of the following pairs of equations could be used to determine the location on the horizontal surface where the two cars will meet, and why? A x=x0+v0xt+12axt2x=x0+v0xt+12axt2 for car WW, and x=x0+v0xt+12axt2x=x0+v0xt+12axt2 for car ZZ. Since the cars will meet at the same time, solving for tt in one equation and placing the new expression for tt into the other equation will eliminate all unknown variables except xx. B x=x0+v0xt+12axt2x=x0+v0xt+12axt2 for car WW, and Δx=x−x0Δx=x−x0 for car ZZ. Since the separation distance is known between both cars, the displacement for car ZZ can be used in the equation for car WW so that the time at which the cars meet can be determined. Once known, the time can be used to determine the meeting location. C Δx=x−x0Δx=x−x0 for car WW, and x=x0+v0xt+12axt2x=x0+v0xt+12axt2 for car ZZ. Since the separation distance is known between both cars, the displacement for car WW can be used in the equation for car ZZ so that the time at which the cars meet can be determined. Once known, the time can be used to determine the meeting location. D Δx=x−x0Δx=x−x0 for car WW, and Δx=x−x0Δx=x−x0 for car ZZ. Since the location at which the cars meet represents the final position of both cars, the separation distance for both cars can be substituted into both equations to determine the final position of both cars.

A x=x0+v0xt+12axt2x=x0+v0xt+12axt2 for car WW, and x=x0+v0xt+12axt2x=x0+v0xt+12axt2 for car ZZ. Since the cars will meet at the same time, solving for tt in one equation and placing the new expression for tt into the other equation will eliminate all unknown variables except xx.

A scientist designs an experiment that requires two atomic particles whose only fundamental force exerted between them is the gravitational force. Which combination of particles and separation distance will meet this condition? A proton and neutron within an atomic nucleus Answer A: A proton and neutron within an atomic nucleus A A proton and electron within the same atom Answer B: A proton and electron within the same atom B A proton and neutron located 1.0 mm apart Answer C: A proton and neutron located 1.0 mm apart C A proton and electron located 1.0 cm apart

A proton and neutron located 1.0 mm apart Answer C: A proton and neutron located 1.0 mm apart C

In which of the following situations is the gravitational force the dominant force? Select two answers. A satellite is in orbit around a planet. Answer A: A satellite is in orbit around a planet. A An object is in free fall just after it is released from rest. Answer B: An object is in free fall just after it is released from rest. B An electron and a proton are bound together in an atom. Answer C: An electron and a proton are bound together in an atom. C A proton and a neutron are bound together in an atom's nucleus.

A satellite is in orbit around a planet. Answer A: A satellite is in orbit around a planet. A An object is in free fall just after it is released from rest.

A ball traveling at a speed ν0ν0 rolls off a desk and lands at a horizontal distance x0x0 away from the desk, as shown in the figure. The ball is then rolled off of the same desk at a speed of 3 v03 v0. At what horizontal distance will the ball land from the table? A x0x0 B 3x03x0 C 6x06x0 D 9x0

B 3x03x0

A 2 kg object is released from rest near the surface of a planet with a negligible atmosphere. A graph of the object's speed v as a function of time t is shown. What is the weight of the object on the planet? 2 N Answer A: 2 newtons A 8 N Answer B: 8 newtons B 10 N Answer C: 10 newtons C 20 N

B 8 N

A student pulls a block over a rough surface with a constant force FPFP that is at an angle θθ above the horizontal, as shown above. If FPFP remains constant but the angle θθ is increased, which of the following is true at some later time? A The force of friction between the block and surface will increase. B The force of friction between the block and surface will decrease. C The weight of the block will increase. D The weight of the block will decrease.

B The force of friction between the block and surface will decrease.

A student uses an electronic force sensor to study how much force the student's finger can apply to a specific location. The student uses one finger to apply a force on the sensor, and data collected from two trials are shown in the table. During which trial, if any, does the student's finger experience the greatest electromagnetic force? A Trial 1, because the student's finger did not apply a force to the sensor. B Trial 2, because the student's finger applied the largest force to the sensor. C An electromagnetic force is not exerted on the student's finger for any trial because the sensor does not apply any force to the student's finger. D An electromagnetic force is not exerted on the student's finger for any trial because the only force that the sensor applies to the student's finger is a normal force.

B Trial 2, because the student's finger applied the largest force to the sensor.

A student must design an experiment to determine the acceleration of a cart that rolls down a small incline after it is released from rest. The student has access to a timer, a meterstick, and a slow-motion camera that takes a photograph every 160160 of a second. The angle that the incline makes with the horizontal is unknown, and the length of the incline is unknown. Which of the following procedures could the student use to determine the cart's acceleration? Select two answers. A Use the meterstick to measure the vertical height of the incline, and use the timer to record the time it takes for the cart to travel down the incline. B Use the timer to record the time it takes the cart to travel alongside a meterstick that is attached to the incline. C Use the slow-motion camera to film the cart as it rolls down the incline alongside a meterstick that is attached to the incline. D Use the slow-motion camera to film the cart as it rolls down the incline alongside a timer that is attached to the incline.

B Use the timer to record the time it takes the cart to travel alongside a meterstick that is attached to the incline. C Use the slow-motion camera to film the cart as it rolls down the incline alongside a meterstick that is attached to the incline.

Identical objects, Object XX and Object YY, are tied together by a string and placed at rest on an incline, as shown in the figure. The distance between the center of mass of each object is 2m2m. The system of the two objects is released from rest, and a graph of the system's center of mass velocity as a function of time is shown. Based on the data, approximately how much time will it take the center of mass of Object XX to reach point JJ near the bottom of the incline? A 2.7s2.7s B 2.8s2.8s C 3.0s3.0s D 3.5s

C 3.0s3.0s

Two objects, XX and YY, move toward one another and eventually collide. Object XX has a mass of 2M2M and is moving at a speed of 2v02v0 to the right before the collision. Object YY has a mass of MM and is moving at a speed of v0v0 to the left before the collision. Which of the following describes the magnitude of the forces FF the objects exert on each other when they collide? A The force exerted by XX on YY is 4F4F to the right, and the force exerted by YY on XX is FF to the left. B The force exerted by XX on YY is 2F2F to the right, and the force exerted by YY on XX is FF to the left. C The force exerted by XX on YY is FF to the right, and the force exerted by YY on XX is FF to the left. D The force exerted by XX on YY is FF to the left, and the force exerted by YY on XX is FF to the right.

C The force exerted by XX on YY is FF to the right, and the force exerted by YY on XX is FF to the left.

A satellite orbits Earth. The only force on the satellite is the gravitational force exerted by Earth. How does the satellite's acceleration compare to the gravitational field at the location of the satellite? Select two answers. A The gravitational field strength is unrelated to the acceleration. B The gravitational field strength is smaller than the acceleration. C The gravitational field and the acceleration point in the same direction. D The magnitudes of the acceleration and the gravitational field strength are equal.

C The gravitational field and the acceleration point in the same direction. D The magnitudes of the acceleration and the gravitational field strength are equal.

A spring-loaded launcher has a mass of 0.60 kg0.60 kg and is placed on a platform 1.2m1.2m above the ground. The force of friction is negligible between the platform and the launcher. The launcher fires a 0.30kg0.30kg ball that lands a distance DD to the right of the platform, as shown in the diagram above. Which of the following explanations is true? A The launcher will not fall off the platform because only the ball receives an applied force. B The launcher will fall off the platform and land D3D3 to the left of the platform because the mass of the system is three times the mass of the ball. C The launcher will fall off the platform and land D2D2 to the left of the platform because the launcher is twice the mass of the ball. D The launcher will fall off the stand and land DD to the left of the stand because the force is the same on both objects.

C The launcher will fall off the platform and land D2D2 to the left of the platform because the launcher is twice the mass of the ball.

An object is launched upward at angle θ0θ0 above the horizontal with a speed of v0v0. The trajectory and three positions of the object, XX, YY, and ZZ, are shown in the figure. Position XX is higher than position ZZ with respect to the ground, and position YY is at the object's maximum vertical position. Which of the following claims is correct about the system that consists of only the object? A The speed of the object at position XX is greater than the speed of the object at position ZZ. B The object's speed at point ZZ is v0v0. C The object's acceleration is the same at positions XX, YY, and ZZ. D The object is at rest at position YY.

C The object's acceleration is the same at positions XX, YY, and ZZ.

The table shows the vertical position as a function of time for an object that is dropped from a height of 5 m5 m. A student must determine the acceleration of the object. Which of the following procedures could the student use to make the determination? Justify your selections. Select two answers. A Create a graph of yy as a function of t2t2, since the slope will be equal to the acceleration due to gravity. B Use vy¯¯¯=ΔyΔtvy¯=ΔyΔt to determine the average vertical speed of the ball, and then divide the average speed by the time in which the ball was in the air, since the average speed and time interval is used to determine an object's acceleration. C Use y=y0+vy0t+12ayt2y=y0+vy0t+12ayt2, since all quantities are known except for the acceleration due to gravity. D Create a position-versus-time graph of the ball's motion, and use the data to create a velocity-versus-time graph of the ball's motion, since the slope of the velocity-versus-time graph represents the acceleration.

C Use y=y0+vy0t+12ayt2y=y0+vy0t+12ayt2, since all quantities are known except for the acceleration due to gravity. D Create a position-versus-time graph of the ball's motion, and use the data to create a velocity-versus-time graph of the ball's motion, since the slope of the velocity-versus-time graph represents the acceleration.

Block AA is placed on a rough surface inclined at an angle θθ above the horizontal. A taut string connects block AA over a pulley to block BB, which hangs from the string, as shown below. The masses of blocks AA and BB are MAMA and MBMB, respectively. At time t=0t=0, block AA is sliding up the slope as block BB falls, and the blocks are both slowing down. Assume that the mass and friction of the pulley are negligible. If the mass of block BB is 2kg2kg, the gravitational force exerted on block BB is most nearly which of the following? A 0.2N0.2N B 2N2N C 20N20N D It is impossible to determine without knowing the mass of block AA.

C 20N

The amusement park ride shown above takes riders straight up a tall tower and then releases an apparatus holding seats. This apparatus free-falls back to Earth and is stopped safely right above the ground. Which of the following indicates the magnitude of the gravitational force exerted on a rider of mass mm on the way up and on the way down? A Way UpWay DownZeroZero B Way UpWay DownLess than mgmgEqual to mgmg C Way UpWay DownEqual to mgmgEqual to mgmg D Way UpWay DownGreater than mgmgZero

C Way UpWay DownEqual to mgmgEqual to mgmg

A student uses a motion sensor to collect data of the velocity of an object as a function of time during two experimental trials, as shown. In which trial does the object have the greatest magnitude of acceleration, and in which trial does the object travel the greatest distance? A Greatest Magnitude of AccelerationGreatest DistanceTrial 1Trial 1 B Greatest Magnitude of AccelerationGreatest DistanceTrial 2Trial 2 C Greatest Magnitude of AccelerationGreatest DistanceTrial 1Trial 2 D Greatest Magnitude of AccelerationGreatest DistanceTrial 2Trial 1

D Greatest Magnitude of AccelerationGreatest DistanceTrial 2Trial 1

A student drops a rock from rest at a distance hh above the ground such that the rock hits the ground at time t0t0. At what distance above the ground should the rock be dropped such that it hits the ground at a time 2t02t0 after it is released from rest? A hh B 2h2h C 3h3h D 4h

D 4h

A block is placed on an inclined plane and remains stationary, as shown in the figure above. A student claims, "The block remains stationary because as gravity tries to pull the block down the ramp, the block exerts an equal and opposite force on itself up the ramp." Is the student's claim correct? Justify your answer. A Yes. Newton's first law states the block must remain stationary unless pushed. B Yes. Newton's third law states the block must exert a force equal and opposite to gravity. C No. Newton's first law states the block's inertia must cause it to move down the ramp. D No. Newton's third law states the block cannot exert a force on itself.

D No. Newton's third law states the block cannot exert a force on itself.

Identical spheres are dropped from a height of 100m100m above the surfaces of both Planet XX and Planet YY. The position of the spheres as a function of time is recorded as the spheres fall. These data are shown in the graphs above. Which planet exerts a greater gravitational force on the sphere, and what evidence supports this conclusion? A Planet XX, because the object's final speed is greater. B Planet XX, because the object's time of fall is greater. C Planet YY, because the area under the curve is smaller. D Planet YY, because the magnitude of the slope of the curve increases at a faster rate.

D Planet YY, because the magnitude of the slope of the curve increases at a faster rate.

A ball of Mass MM is swung in a vertical circle with a constant tangential speed. Figure 1 shows the forces exerted on the ball at the top of the circle, and Figure 2 shows the forces exerted on the ball at the bottom of the circle. Which of the following is an expression for the centripetal acceleration of the ball in terms of MM, T1T1, T2T2, and any fundamental constants? T2−T12MT2−T12M Answer A: the fraction with numerator T sub 2, minus T sub 1, and denominator 2 M, end fraction A gg Answer B: g B T1−T22MT1−T22M Answer C: the fraction with numerator T sub 1, minus T sub 2, and denominator 2 M, end fraction C T1+T22M

D T1+T22M

A 1500kg car traveling along a road is hit by a 0.1kg0.1kgrock that creates a small crack in the car's windshield. Which of the following describes the interaction between the windshield and the rock? A The car exerts a force on the rock, but the rock does not exert a force on the car. B The rock exerts a force on the car, but the car does not exert a force on the rock. C The car exerts a force on the rock, and the rock exerts a force on the car. The two forces are not equal in magnitude. D The car exerts a force on the rock, and the rock exerts a force on the car. The two forces are equal in magnitude.

D The car exerts a force on the rock, and the rock exerts a force on the car. The two forces are equal in magnitude.

Two students, Student XX and Student YY, stand on a long skateboard that is at rest on a flat, horizontal surface, as shown. In order to get the student-student-skateboard system to accelerate, Student XX claims that Student YY should apply a force on Student XX while both students stand on the skateboard. Which of the following statements is true regarding the claim made by Student XX? A The claim is correct because Newton's second law states that an object will accelerate if a net force is applied to the object. B The claim is correct because Student YY can apply a force that is greater in magnitude than the frictional forces that are exerted on the student-student-skateboard system C The claim is incorrect because Student YY cannot apply a force that is greater in magnitude than the frictional forces that are exerted on the student-student-skateboard system D The claim is incorrect because both students are internal to the student-student-skateboard system, and internal forces within a system cannot cause the system to accelerate.

D The claim is incorrect because both students are internal to the student-student-skateboard system, and internal forces within a system cannot cause the system to accelerate.

Students connect a spring scale to a block on a rough horizontal surface. The students use the spring scale to measure the magnitude of the horizontal force needed to pull the block at a constant speed. Which of the following statements explains why two forces exerted between objects are equal in magnitude? A The gravitational and normal forces exerted on the block, because they are a Newton's third-law pair. B The frictional force and force exerted by the spring scale on the block, because they are a Newton's third-law pair. C The normal force and the frictional force exerted on the block, because objects always exert forces of equal magnitude on each other. D The frictional forces that the block and the surface exert on each other, because objects always exert forces of equal magnitude on each other.

D The frictional forces that the block and the surface exert on each other, because objects always exert forces of equal magnitude on each other.

Which of the following experiments could be used to determine the inertial mass of a block? A Place the block on a rough horizontal surface. Lift one end of the surface up and measure the angle the surface makes with the horizontal at the moment the block begins to slide. B Drop the block from different heights and measure the time of fall from each height. C Place the block on a rough horizontal surface. Give the block an initial velocity and then let it come to rest. Measure the initial velocity and the distance the block moves in coming to rest. D Use a spring scale to exert a force on the block. Measure the acceleration of the block and the applied force.

D Use a spring scale to exert a force on the block. Measure the acceleration of the block and the applied force.

Two identical blocks, block A and block B, are placed on different horizontal surfaces. Block A is initially at rest on a smooth surface, while block B is initially at rest on a rough surface. A constant horizontal force of magnitude F0F0 is exerted on each block. After the force has been applied for a time ΔtΔt, the speeds of blocks A and B are vAvA and vBvB, respectively. Which of the following claims indicates the correct relation between vAvA and vBvB and provides the best justification for the relation? A vA<vBvA<vB. The forces between the atoms in a block and the atoms in a surface oppose the motion of the block and are greater, on average, for block A. B vA<vBvA<vB. The forces between the atoms in a block and the atoms in a surface oppose the motion of the block and are greater, on average, for block B. C vA>vBvA>vB. The forces between the atoms in a block and the atoms in a surface oppose the motion of the block and are greater, on average, for block A. D vA>vBvA>vB. The forces between the atoms in a block and the atoms in a surface oppose the motion of the block and are greater, on average, for block B.

D vA>vBvA>vB. The forces between the atoms in a block and the atoms in a surface oppose the motion of the block and are greater, on average, for block B.

A 5kg5⁢kg object is released from rest near the surface of a planet such that its gravitational field is considered to be constant. The mass of the planet is unknown. After 2s2⁢s, the object has fallen 30m30m. Air resistance is considered to be negligible. What is the gravitational force exerted on the 5kg5⁢kg object near the planet's surface? A 5N5⁢N B 15N15⁢N C 37.5N37.5N D 75N

D 75N

A block of mass MM is attached to a modified Atwood machine and is accelerated upward at 3a3a by a constant force F0F0. What is the weight of the block? A F0−MgF0−Mg B 3Mg3Mg C 2Mg2Mg D Mg

D Mg

Rock XX is released from rest at the top of a cliff that is on Earth. A short time later, Rock YY is released from rest from the same location as Rock XX. Both rocks fall for several seconds before landing on the ground directly below the cliff. Frictional forces are considered to be negligible. After Rock YY is released from rest several seconds after Rock XX is released from rest, what happens to the separation distance SS between the rocks as they fall but before they reach the ground, and why? Take the positive direction to be downward. A. SS is constant because at the moment Rock YY is released, the only difference between the rocks is their difference in height above the ground. B. SS is constant because the difference in speed between the two rocks stays constant as they fall. C. SS increases because the difference in speed between the two rocks increases as they fall. D. SS increases because at all times Rock XX falls with a greater speed than Rock

D. SS increases because at all times Rock XX falls with a greater speed than Rock YY.

Two experiments are conducted are conducted to determine the mass of an object. In Experiment 1, the object's weight is measured by using an electronic balance once the object has been placed at rest on the balance. In Experiment 2, the object is pulled along a horizontal surface with a spring scale such that the force reading on the spring scale remains constant while a motion detector is used to measure the instantaneous speed of the object as it is pulled. All frictional forces for both experiments are considered to be negligible. Which of the two experiments, if either, could be used to determine the gravitational mass of the object? Experiment 1 only Answer A: Experiment 1 only A Experiment 2 only Answer B: Experiment 2 only B both experiments Answer C: both experiments C neither experiment

Experiment 1 only Answer A: Experiment 1 only A

Planet X has a mass of MM and a radius of RR. Planet Y has a mass of 3M3M and a radius of 3R3R. Identical satellites orbit both planets at a distance RR above their surfaces, as shown above. The planets are separated by such a large distance that the gravitational forces between them are negligible. How does the magnitude of the gravitational force FYFY exerted by Planet Y on its satellite compare to the gravitational force FXFX exerted by Planet X on its satellite? FY=3FXFY=3FX Answer A: F sub Y equals, 3 F sub X A FY=32FXFY=32FX Answer B: F sub Y equals, three halves F sub X B FY=34FXFY=34FX Answer C: F sub Y equals, three fourths F sub X C FY=13FX

FY=34FXFY=34FX Answer C: F sub Y equals, three fourths F sub X

An Atwood machine is placed on a planet in which the acceleration due to gravity on the planet is unknown. Both ends of a light string are attached to two blocks such that M1>M2M1>M2 , and the string passes through a pulley such that frictional forces are considered to be negligible, as shown above. The same tension force TT is exerted on both blocks, and the block of mass M1M1 experiences an acceleration a0a0 in the downward direction when released from rest. Which quantities would allow the acceleration due to gravity on the planet to be determined? M1M1 , M2M2 , and a0a0 Answer A: M sub 1 , M sub 2 , and a sub 0 A TT and M1M1 only Answer B: T and M sub 1 only B a0a0 and M1M1 only Answer C: a sub 0 and M sub 1 only C a0a0 only

M1M1 , M2M2 , and a0a0 Answer A: M sub 1 , M sub 2 , and a sub 0 A

A rocket on Earth experiences an upward applied force from its thrusters. As a result of this force, the rocket accelerates upward at 2 m/s2. Assume that there are no other upward forces exerted on the rocket and that wind resistance is negligible. Which of the following combinations of the rocket's mass mRocket and force from its thrusters FThrusters would result in an upward acceleration of 2 m/s2? Select two answers. MRocket1kgFThrusters12N Answer A: M sub Rocket: 1 kilogram. F sub Thrusters: 12 newtons. A MRocket2kgFThrusters4N Answer B: M sub Rocket: 2 kilograms. F sub Thrusters: 4 newtons. B MRocket3kgFThrusters6N Answer C: M sub Rocket: 3 kilograms. F sub Thrusters: 6 newtons. C MRocket3kgFThrusters36N

MRocket1kgFThrusters12N Answer A: M sub Rocket: 1 kilogram. F sub Thrusters: 12 newtons. A MRocket3kgFThrusters36N

A student must conduct two experiments so that the inertial mass and gravitational mass of the same object can be determined. In the experiment to find the object's gravitational mass, the student ties one end of a string around the object with the other end tied to a spring scale so that the object can vertically hang at rest. In the experiment to find the object's inertial mass, the student uses a spring scale to pull the object, starting from rest, across a horizontal surface with a constant applied force such that frictional forces are considered to be negligible. In addition to the spring scale, the student has access to other measuring devices commonly found in a science laboratory. Which of the following lists the essential measuring devices the student can use to collect the data necessary to find the object's gravitational and inertial mass? Meterstick and timer Answer A: Meterstick and timer A Meterstick, timer, and motion detector Answer B: Meterstick, timer, and motion detector B Meterstick, timer, motion detector, and mass balance Answer C: Meterstick, timer, motion detector, and mass balance C Meterstick, timer, motion detector, mass balance, and protractor

Meterstick and timer Answer A: Meterstick and timer A

Student X ties one end of a string to a 0.5 kg ball and swings the ball in a vertical circle of radius 1 m, as shown in the figure. Student Y uses video analysis to determine the speed of the ball at points A, B, C, and D, as shown in the table. Student X states that the data are incorrect because the tension in the string provides a centripetal force that should cause the ball to travel with a constant tangential speed. Is Student X's reasoning correct, and why or why not? Yes, because the tension force from the string is the only force that is directed inward at all points along the ball's circular path. Answer A: Yes, because the tension force from the string is the only force that is directed inward at all points along the ball's circular path. A Yes, because centripetal acceleration of the ball should be constant at all points along the ball's circular path. Answer B: Yes, because centripetal acceleration of the ball should be constant at all points along the ball's circular path. B No, because a centrifugal force that is directed outward is exerted on the ball at all points along the ball's circular path. Answer C: No, because a centrifugal force that is directed outward is exerted on the ball at all points along the ball's circular path. C No, because the net centripetal force exerted on the ball is the combination of the tension force from the string and the force due to gravity from Earth.

No, because the net centripetal force exerted on the ball is the combination of the tension force from the string and the force due to gravity from Earth.

A student uses a motion sensor to collect data about an object's velocity v as a function of time t after it is released from rest near Earth's surface. The student claims that the graph shown represents the object while in free fall. Does the data from the graph support the student's claim? Yes, because the graph shows that the object's speed increases as it falls, which is consistent for an object that is in free fall. Answer A: Yes, because the graph shows that the object's speed increases as it falls, which is consistent for an object that is in free fall. A Yes, because the graph shows that the object's velocity is downward as it falls, which is consistent for an object that is in free fall. Answer B: Yes, because the graph shows that the object's velocity is downward as it falls, which is consistent for an object that is in free fall. B No, because the area under the curve of the graph indicates that the acceleration is increasing, which indicates that a force other than gravity is exerted on the object. Answer C: No, because the area under the curve of the graph indicates that the acceleration is increasing, which indicates that a force other than gravity is exerted on the object. C No, because the slope of the curve of the graph indicates that the acceleration is less than g, which indicates that a force other than gravity is exerted on the object.

No, because the slope of the curve of the graph indicates that the acceleration is less than g, which indicates that a force other than gravity is exerted on the object.

An object is placed on a rotating disk. The amount of time it takes the object to make one revolution around the center of the circle may be set at a known value. Which of the following procedures could be used to make the necessary measurements to find the coefficient of static friction between the object and the disk's surface? Place the object on the edge of the disk. Set the disk to rotate at a tangential speed for the object such that the object does not slide. Use a stopwatch to measure the time it takes for the object to make one revolution. Use a balance to determine the mass of the object. Answer A: Place the object on the edge of the disk. Set the disk to rotate at a tangential speed for the object such that the object does not slide. Use a stopwatch to measure the time it takes for the object to make one revolution. Use a balance to determine the mass of the object. A Place the object on the disk and measure the distance from the center of the disk to the center of mass of the object by using a meterstick. Slowly increase the rate the disk rotates until the object begins to slide off the disk. Record the time in which the object makes one revolution around the center of the disk. Use a balance to determine the mass of the object. Answer B: Place the object on the disk and measure the distance from the center of the disk to the center of mass of the object by using a meterstick. Slowly increase the rate the disk rotates until the object begins to slide off the disk. Record the time in which the object makes one revolution around the center of the disk. Use a balance to determine the mass of the object. B Place the object on the disk. Use a motion sensor placed above the disk to measure the tangential speed the object rotates just after the mass begins to slide while increasing the rate at which the disk rotates. Use a balance to determine the mass of the object. Answer C: Place the object on the disk. Use a motion sensor placed above the disk to measure the tangential speed the object rotates just after the mass begins to slide while increasing the rate at which the disk rotates. Use a balance to determine the mass of the object. C Place the object on the disk and measure the distance from the center of the disk to the center of mass of the object by using a meterstick. Slowly increase the rate the disk rotates until the object begins to slide off the disk. Record the time in which the object makes one revolution around the center of the disk.

Place the object on the disk and measure the distance from the center of the disk to the center of mass of the object by using a meterstick. Slowly increase the rate the disk rotates until the object begins to slide off the disk. Record the time in which the object makes one revolution around the center of the disk.

A student analyzes data of the motion of a planet as it orbits a star that is in deep space. The orbit of the planet is considered to be stable and does not change over time. The student claims, "The only experimentally measurable external force exerted on the planet is the force due to gravity from the star." Is the student's claim supported by the evidence? What reasoning either supports or contradicts the student's claim? Yes. Other external forces are exerted on the planet, but they are of negligible magnitude. Answer A: Yes. Other external forces are exerted on the planet, but they are of negligible magnitude. A Yes. The only external force exerted on the planet is the force due to gravity from the star. Answer B: Yes. The only external force exerted on the planet is the force due to gravity from the star. B No. The strong nuclear forces, weak nuclear forces, and the electromagnetic forces exerted on the planet could be measured. Answer C: No. The strong nuclear forces, weak nuclear forces, and the electromagnetic forces exerted on the planet could be measured. C No. There are no external forces exerted on the planet.

Yes. Other external forces are exerted on the planet, but they are of negligible magnitude. Answer A: Yes. Other external forces are exerted on the planet, but they are of negligible magnitude. A

Satellite AA orbits a planet at a distance dd from the planet's center with a centripetal acceleration a0a0. A second identical satellite BB orbits the same planet at a distance 2d2d from the planet's center with centripetal acceleration abab. What is the centripetal acceleration abab in terms of a0a0 ? a0/4a0/4 Answer A: a sub 0, over 4 A a0/2a0/2 Answer B: a sub 0, over 2 B 2a02a0 Answer C: 2 a sub 0 C 4a0

a0/4a0/4 Answer A: a sub 0, over 4 A

Planet X has a mass of MM and a radius of RR. Planet Y has a mass of 3M3M and a radius of 3R3R. Identical satellites orbit both planets at a distance RR above their surfaces, as shown above. The planets are separated by such a large distance that the gravitational forces between them are negligible. How does the gravitational field gXgX at the surface of Planet X compare with the gravitational field gYgY at the surface of Planet Y? gX=9gYgX=9gY Answer A: g sub X equals, 9 g sub Y A gX=3gYgX=3gY Answer B: g sub X equals, 3 g sub Y B gX=13gYgX=13gY Answer C: g sub X equals, one third g sub Y C gX=19gY

gX=3gYgX=3gY Answer B: g sub X equals, 3 g sub Y B