Physics Test #3
For what values of x is the speed of the object 0.11 m/s?
+/- .2.52 cm
A car travels at a constant speed of 30.0 mi/h (13.4 m/s) on a level circular turn of radius 50.0 m, as shown in the bird's-eye view in figure a. What minimum coefficient of static friction, μs, between the tires and roadway will allow the car to make the circular turn without sliding?
0,366
A car travels at a constant speed of 33.5 mi/h (15.0 m/s) on a level circular turn of radius 51.0 m, as shown in the bird's-eye view in figure a. What minimum coefficient of static friction, μs, between the tires and the roadway will allow the car to make the circular turn without sliding?
0,450
A dental bracket exerts a horizontal force of 79.7 N on a tooth at point B in the figure. What is the torque on the root of the tooth about point A?
0.640
Use the worked example above to help you solve this problem. Using a small pendulum of length 0.172 m, a geophysicist counts 74.0 complete swings in a time of 60.0 s. What is the value of g in this location?
10.51 m/s^2
A space station shaped like a giant wheel has a radius of 114 m and a moment of inertia of 5.12 ✕ 108 kg · m2. A crew of 150 lives on the rim, and the station is rotating so that the crew experiences an apparent acceleration of 1g. When 100 people move to the center of the station for a union meeting, the angular speed changes. What apparent acceleration is experienced by the managers remaining at the rim? Assume that the average mass of each inhabitant is 65.0 kg.
13.008 m/s^2
A sample of blood is placed in a centrifuge of radius 13.0 cm. The mass of a red blood cell is 3.0 ✕ 10−16 kg, and the magnitude of the force acting on it as it settles out of the plasma is 4.0 ✕ 10−11 N. At how many revolutions per second should the centrifuge be operated?
161.025 rev/s
If the angular acceleration were doubled for the same duration, by what factor would the angular displacement change?
2
The fishing pole in the figure below makes an angle of 20.0° with the horizontal. What is the magnitude of the torque exerted by the fish about an axis perpendicular to the page and passing through the angler's hand if the fish pulls on the fishing line with a force F = 125 N at an angle 37.0° below the horizontal? The force is applied at a point L = 1.91 m from the angler's hands.
200.3
A man ties one end of a strong rope 8.57 m long to the bumper of his truck, 0.561 m from the ground, and the other end to a vertical tree trunk at a height of 3.89 m. He uses the truck to create a tension of 7.85 102 N in the rope. Compute the magnitude of the torque on the tree due to the tension in the rope, with the base of the tree acting as the reference point.
2826.66 N*m
If the satellite was placed in an orbit three times farther away, about how long would it take to orbit the Earth once? Answer in days, rounding to one significant figure.
5 days
A bat can detect small objects, such as an insect, whose size is approximately equal to one wavelength of the sound the bat makes. If bats emit a chirp at a frequency of 6.20 104 Hz, and if the speed of sound in air is 343 m/s, what is the smallest insect a bat can detect?
5.53
A satellite of Mars, called Phobos, has an orbital radius of 9.4 ✕ 106 m and a period of 2.8 ✕ 104 s. Assuming the orbit is circular, determine the mass of Mars.
6.27e23 kg
At what maximum speed can a car negotiate a turn on a wet road with coefficient of static friction 0.245 without sliding out of control? The radius of the turn is 27.0 m.
8.05 m/s
Using a small pendulum of length 0.171 m, a geophysicist counts 72.0 complete swings in a time of 60.0 s. What is the value of g in this location?
9.73 m/s^2
Does doubling the initial displacement double the speed of the object at the equilibrium point? Explain. A-Yes, the maximum speed is directly proportional to the initial displacement. B-No, it multiplies the speed at the equilibrium point by sqrt(2). C-No, it multiplies the speed at the equilibrium point by 4. D-No, the speed at the equilibrium point is unaffected.
A
Is the frequency of a wave affected by the wave's amplitude? A-No. They are independent of each other. B-Yes. Increasing amplitude increases frequency. C-Yes. Increasing amplitude decreases frequency.
A
What happens if the woman now leans backwards? (Select all that apply.) A-It depends on whether she leans by moving her feet forward to balance. B-Her side of the board moves upward because the average location of her mass is farther from the fulcrum. C-Nothing, because her weight still acts at the same location on the board. D-Her side of the board moves downward if she keeps legs and feet stationary but grasps the board with her hands to balance. E-Her side of the board moves upward because her weight produces a smaller torque. F-Her side of the board moves upward because she is closer to being horizontal.
A & D
How would the acceleration and tension change if most of the reel's mass were at its rim? (Select all that apply.) A-The acceleration would decrease. B-The tension T would remain the same. C-The acceleration would remain the same. D-The acceleration would increase. E-The tension T would increase. F-The tension T would decrease.
A &E
A hollow cylinder of mass 0.129 kg and radius 3.60 cm has a string wrapped several times around it, as shown in Figure (d). A string is attached to a rigid support and the cylinder allowed to drop from rest. (Indicate the direction with the sign of your answer.) (a) Find the acceleration of the cylinder.(b) Find the speed of the cylinder when a meter of string has unwound off of it.
A- -4.9 m/s^2 B- 3.132 m/s
A block-spring system consists of a spring with constant k = 415 N/m attached to a 1.75 kg block on a frictionless surface. The block is pulled 8.20 cm from equilibrium and released from rest. For the resulting oscillation, find the amplitude, angular frequency, frequency, and period. What is the maximum value of the block's velocity and acceleration? A-amplitude (in m) B-angular frequency (in rad/s) C- frequency (in Hz) D- period (in s) E- maximum velocity (in m/s) F-maximum acceleration (in m/s2)
A- 0.0820 B-15.4 C-2.451 D-0.408 E-1.2628 F-19.447
A woman of mass m = 53.3 kg sits on the left end of a seesaw—a plank of length L = 3.86 m, pivoted in the middle as shown in the figure. (a) First compute the torques on the seesaw about an axis that passes through the pivot point. Where should a man of mass M = 74.6 kg sit if the system (seesaw plus man and woman) is to be balanced? (b) Find the normal force exerted by the pivot if the plank has a mass of mpl = 13.5 kg. (c) Repeat part (a), but this time compute the torques about an axis through the left end of the plank.
A- 1.38 m B- 1385.72 N C- 1.38 m
A woman of mass m = 55.0 kg sits on the left end of a seesaw—a plank of length L = 4.00 m, pivoted in the middle as in the figure. (a) First compute the torques on the seesaw about an axis that passes through the pivot point. Where should a man of mass M = 75.0 kg sit if the system (seesaw plus man and woman) is to be balanced? (b) Find the normal force exerted by the pivot if the plank has a mass of mpl = 12.0 kg. (c) Repeat part (a), but this time compute the torques about an axis through the left end of the plank.
A- 1.47 M B- 1.39E3 N C- 1.46 m
A 49.0-kg child takes a ride on a Ferris wheel that rotates four times each minute and has a diameter of 17.0 m. r=8.5 w=4.00 rev/min (a) What is the centripetal acceleration of the child? (b) What force (magnitude and direction) does the seat exert on the child at the lowest point of the ride? (c) What force does the seat exert on the child at the highest point of the ride? (d) What force does the seat exert on the child when the child is halfway between the top and bottom?
A- 1.4914 m/s^2 B- 553.21 N upward C- 407.19 upward away D- 73.01 N Mag= 485.519 N Direction= 81.35
(a) Find the angle through which the wheel rotates between t = 2.00 s and t = 3.10 s. (b) Find the angular speed when t = 3.10 s. (c) What is the magnitude of the angular speed five revolutions following t = 3.10 s? 3.85 rad/s^2 1.50 rad/s ti=0
A- 12.34 RAD B- 13.435 RAD/S C- 20.55 RAD/S
(a) What are the angular speed and angular displacement of the disc 0.340 s after it begins to rotate? (b) Find the tangential speed at the rim at this time. .0445 m 40.1 rad/s^2
A- 13.63 rad/s & 2.43 rad B- .6065 m/s
Mars rotates on its axis once every 1.02 days (almost the same as Earth does). (a) Find the distance from Mars at which a satellite would remain in one spot over the Martian surface. (Use 6.42 1023 kg for the mass of Mars.) (b) Find the speed of the satellite.
A- 2.03e7 B-1450.69
A star with an initial radius of 1.00 108 m and period of 30.0 days collapses suddenly to a radius of 1.00 104 m. (a) Find the period of rotation after collapse. (b) Find the work done by gravity during the collapse if the mass of the star is 2.00 1030 kg. (c) What is the speed of an indestructible person standing on the equator of the collapsed star? (Neglect any relativistic or thermal effects, and assume the star is spherical before and after it collapses).
A- 2.6e-2 s B- 234.25e40 J C- 2.42e6 m/s
The tires on a new compact car have a diameter of 2.0 ft and are warranted for 62,000 miles. (a) Determine the angle (in radians) through which one of these tires will rotate during the warranty period. (b) How many revolutions of the tire are equivalent to your answer in (a)?
A- 3.27e8 rad B- 5.21e7 rev
The International Space Station has a mass of 4.19 ✕ 105 kg and orbits at a radius of 6.79 ✕ 106 m from the center of Earth. Find the gravitational force exerted by Earth on the space station, the space station's gravitational potential energy, and the weight of a 93.3 kg astronaut living inside the station. A-the gravitational force (in N) exerted by Earth on the space station (Enter the magnitude.) B- the gravitational force (in N) exerted by Earth on the space station (Enter the magnitude.) C- the weight (in N) of an 93.3 kg astronaut living inside the station
A- 3.6E6 B- -2.457e13 C- 806.10 N
A jet traveling at a speed of 2.00 102 m/s executes a vertical loop with a radius of 7.25 102 m. (See Figure (b).) Find the magnitude of the force of the seat on a 70.0-kg pilot at the following positions. (a) the top of the loop (b) the bottom of the loop
A- 3176 N B- 4548 N
A 50.0-kg child stands at the rim of a merry-go-round of radius 2.50 m, rotating with an angular speed of 3.70 rad/s. (a) What is the child's centripetal acceleration? (b) What is the minimum force between her feet and the floor of the carousel that is required to keep her in the circular path? (c) What minimum coefficient of static friction is required? Is the answer you found reasonable? In other words, is she likely to stay on the merry-go-round?
A- 34.225 m/s^2 B- 1711.25 N C- 3.4887 No
A compact disc rotates from rest up to an angular speed of 31.4 rad/s in a time of 0.892 s. (a) What is the angular acceleration of the disc, assuming the angular acceleration is uniform? (b) Through what angle does the disc turn while coming up to speed? (c) If the radius of the disc is 4.45 cm, find the tangential speed of a microbe riding on the rim of the disc when t = 0.892 s. (d) What is the magnitude of the tangential acceleration of the microbe at the given time?
A- 35.2 rad/s^2 B-14 rad C-1.40 m/s D-1.57 m/s^2
From a telecommunications point of view, it's advantageous for satellites to remain at the same location relative to a location on Earth. This can occur only if the satellite's orbital period is the same as the Earth's period of rotation, approximately 24.0 h. (a) At what distance from the center of the Earth can this geosynchronous orbit be found? (b) What's the orbital speed of the satellite?
A- 4.23E7 m B- 3.08E3 m/s
When four people with a combined mass of 295 kg sit down in a 2000-kg car, they find that their weight compresses the springs an additional 0.60 cm. (a) What is the effective force constant of the springs? (b) The four people get out of the car and bounce it up and down. What is the frequency of the car's vibration?
A- 4.81 e5 B- 2.468
A student sits on a pivoted stool while holding a pair of weights. (See Figure) The stool is free to rotate about a vertical axis with negligible friction. The moment of inertia of student, weights, and stool is 2.25 kg · m2. The student is set in rotation with arms outstretched, making one complete turn every 1.26 s, arms outstretched. (a) What is the initial angular speed of the system? (b) As he rotates, he pulls the weights inward so that the new moment of inertia of the system (student, objects, and stool) becomes 1.80 kg · m2. What is the new angular speed of the system? (c) Find the work done by the student on the system while pulling in the weights. (Ignore energy lost through dissipation in his muscles.)
A- 4.99 rad/s B- 6.24 rad/s C- 7.03 J
A compact disc rotates from rest up to an angular speed of 34.6 rad/s in a time of 0.863 s. (a) What is the angular acceleration of the disc, assuming the angular acceleration is uniform? (b) Through what angle does the disc turn while coming up to speed? (c) If the radius of the disc is 4.45 cm, find the tangential speed of a microbe riding on the rim of the disc. (d) What is the magnitude of the tangential acceleration of the microbe at the given time?
A- 40.44 rad/s^2 B- 15.06 rad C- 1.54 m/s D- 1.78 m/s^2
(a) A man applies a force of F = 3.00 102 N at an angle of 60.0° to a door, x = 1.60 m from the hinges. Find the torque on the door, choosing the position of the hinges as the axis of rotation. (b) Suppose a wedge is placed 1.50 m from the hinges on the other side of the door. What minimum force must the wedge exert so that the force applied in part (a) won't open the door?
A- 415.68 N*m B- 277.12 N
A car initially traveling eastward turns north by traveling in a circular path at uniform speed as shown in the figure below. The length of the arc ABC is 205 m, and the car completes the turn in 38.0 s. (a) Determine the car's speed. (b) What is the magnitude and direction of the acceleration when the car is at point B?
A- 5.39 m/s B- mag= 0.223 direction= 145 (wrong)
(a) A man applies a force of F = 3.00 102 N at an angle of 60.0° to the door of Figure (a), 2.00 m from well-oiled hinges. Find the torque on the door, choosing the position of the hinges as the axis of rotation. (b) Suppose a wedge is placed 1.50 m from the hinges on the other side of the door. What minimum force must the wedge exert so that the force applied in part (a) won't open the door?
A- 520 n*m B- 347 N
A race car accelerates uniformly from a speed of 40.0 m/s to a speed of 60.0 m/s in 5.00 s while traveling counterclockwise around a circular track of radius 4.00 102 m. When the car reaches a speed of 50.0 m/s, calculate (a) the magnitude of the car's centripetal acceleration, (b) the angular speed, (c) the magnitude of the tangential acceleration, and (d) the magnitude of the total acceleration.
A- 6.25 M/S^2 B- 0.125 rad/s C-4 m/s^2 D- 7.42 m/s^2
(a) Calculate the angular momentum of Earth that arises from its spinning motion on its axis, treating Earth as a uniform solid sphere. (b) Calculate the angular momentum of Earth that arises from its orbital motion about the Sun, treating Earth as a point particle.
A- 7.07e33 j*s B- 2.663e40 j*s
A man enters a tall tower, needing to know its height. He notes that a long pendulum extends from the ceiling almost to the floor and that its period is 17.5 s. (a) How tall is the tower? (b) If this pendulum is taken to the Moon, where the free-fall acceleration is 1.67 m/s2, what is the period there?
A- 76.02 B- 42.4
A satellite is in a circular orbit around the Earth at an altitude of 2.47 106 m. (a) Find the period of the orbit. h=2.47e6 (b) Find the speed of the satellite. (c) Find the acceleration of the satellite.
A- 8.85e6 m B- 2.3 h C-5.09 m/s^2
A 0.485 kg object connected to a light spring with a spring constant of 22.0 N/m oscillates on a frictionless horizontal surface. (a) Calculate the total energy of the system and the maximum speed of the object if the amplitude of the motion is 3.00 cm. (b) What is the velocity of the object when the displacement is 2.00 cm? (c) Compute the kinetic and potential energies of the system when the displacement is 2.00 cm.
A- 9.9e-3 J .202m/s B- +/-.151 m/s c- 5.53e-3 J . 4.4e-3 J
A bicycle wheel has a diameter of 64.6 cm and a mass of 1.85 kg. Assume that the wheel is a hoop with all of the mass concentrated on the outside radius. The bicycle is placed on a stationary stand and a resistive force of 124 N is applied tangent to the rim of the tire. (a) What force must be applied by a chain passing over a 8.90-cm-diameter sprocket in order to give the wheel an acceleration of 4.47 rad/s2? (b) What force is required if you shift to a 5.66-cm-diameter sprocket?
A- 919.43 N B- 1448.07 kN
A 0.500-kg object connected to a light spring with a spring constant of 20.0 N/m oscillates on a frictionless horizontal surface. (a) Calculate the total energy of the system and the maximum speed of the object if the amplitude of the motion is 3.00 cm. (b) What is the velocity of the object when the displacement is 2.00 cm? (c) Compute the kinetic and potential energies of the system when the displacement is 2.00 cm.g
A- 9e-3 J & 0,190 m/s B- +/- .141 m/s C- 4.97e-3 J & 4e-3 J
A solid, frictionless cylindrical reel of mass M = 3.00 kg and radius R = 0.400 m is used to draw water from a well (Figure (a)). A bucket of mass m = 2.00 kg is attached to a cord that is wrapped around the cylinder. (a) Find the tension T in the cord and acceleration a of the bucket. (b) If the bucket starts from rest at the top of the well and falls for 3.00 s before hitting the water, how far does it fall?
A- a=-5.60 T=8.40N B- -25.2 m
A 70.0-kg woman stands at the rim of a horizontal turntable having a moment of inertia of 440 kg · m2 and a radius of 2.00 m. The turntable is initially at rest and is free to rotate about a frictionless vertical axle through its center. The woman then starts walking around the rim clockwise (as viewed from above the system) at a constant speed of 1.50 m/s relative to the Earth. (a) In what direction does the turntable rotate? (b) With what angular speed does the turntable rotate? (c) How much work does the woman do to set herself and the turntable into motion?
A- counterclockwise B- 0.477 rad/s C- 128.806 J
A race track is constructed such that two arcs of radius 80 m at A and 40 m at B are joined by two stretches of straight track as in the figure below. In a particular trial run, a driver travels at a constant speed of 50 m/s for one complete lap. (a) The ratio of the tangential acceleration at A to that at B is which of the following? A-1/2 B-1/4 C-2 D-4 E-The tangential acceleration is zero at both points. (b) The ratio of the centripetal acceleration at A to that at B is which of the following? A-1/2 B-1/4 C-2 D-4 E-The tangential acceleration is zero at both points. (c) The angular speed is greatest at which of the following? A-A B-B C-It is equal at both A and B.
A- e B- a c- b
Figure (a) shows a roller-coaster car moving around a circular loop of radius R. (a) What speed must the car have at the top of the loop so that it will just make it over the top without any assistance from the track? (b) What speed will the car subsequently have at the bottom of the loop? (c) What will be the normal force on a passenger at the bottom of the loop if the loop has a radius of 10.0 m?
A- sqr. gR B- sqr. 5gR C- 6 mg
A solid, frictionless cylinder reel of mass M = 2.52 kg and radius R = 0.378 m is used to draw water from a well (see Figure (a)). A bucket of mass m = 1.76 kg is attached to a cord that is wrapped around the cylinder. (Indicate the direction with the sign of your answer.) (a) Find the tension T in the cord and acceleration a of the bucket. (b) If the bucket starts from rest at the top of the well and falls for 3.13 s before hitting the water, how far does it fall?
A- t=7.19 N a=-5.71 m/s^2 B- -27.97 m
The free-fall acceleration on Mars is 3.7 m/s2. (a) What length pendulum has a period of 1.1-s on Earth? (b) What length pendulum would have a 1.1-s period on Mars? (c) An object is suspended from a spring with force constant 10 N/m. Find the mass suspended from this spring that would result in a 1.1 s period on Earth. (d) An object is suspended from a spring with force constant 10 N/m. Find the mass suspended from this spring that would result in a 1.1 s period on Mars.
A-30 cm B- 11.3 cm C-0.306 kg D-0.306 kg
A dentist's drill starts from rest. After 4.50 s of constant angular acceleration it turns at a rate of 2.45 ✕ 104 rev/min. (a) Find the drill's angular acceleration. (b) Determine the angle (in radians) through which the drill rotates during this period.
A-570.14 rad/s^2 B- 5772.6675 rad
(a) Find the amplitude, frequency, and period of motion for an object vibrating at the end of a horizontal spring if the equation for its position as a function of time is x = (0.250 m) cos(π/8.00*t) . (b) Find the maximum magnitude of the velocity and acceleration. (c) What are the position, velocity, and acceleration of the object after 1.00 s has elapsed?
A: A= .250 m w= .393 f= .0625 T= 16.0 B: vmax: .0983 m/s amax: 0.0386 m/s C: x=0.231 m v=-0.0376 m/s a=-0.0357 m/s^2
(a) Find the amplitude, frequency, and period of motion for an object vibrating at the end of a horizontal spring if the equation for its position as a function of time is the following. x = (0.205 m) cos π 8.00 t (b) Find the maximum magnitude of the velocity and acceleration.(c) What are the position, velocity, and acceleration of the object after 1.35 s has elapsed?
A: A=.205 f=0.06 T=16 B: vmax:0.081 m/s amas: 0,03167 m/s^2 C: x=? v=-0.0408 m/s a=-0.0273
If the object-spring system is described by x = (0.315 m) cos (1.45t), find the following. (a) the amplitude, the angular frequency, the frequency, and the period (b) the maximum magnitudes of the velocity and the acceleration (c) the position, velocity, and acceleration when t = 0.250 s
A: A=0.315 w=1.45 rad/s f=0.23077 Hz T= 4.333 s B: vmax: 0.45675 m/s amax: 0.6622875 m/s^2 C: x=0.2945 m v=-0.1620 m/s a=-0.6192 m/s^2
Use the worked example above to help you solve this problem. A wave traveling in the positive x-direction is pictured in Figure (a). Find the amplitude, wavelength, speed, and period of the wave if it has a frequency of 7.70 Hz. In Figure (a), Δx = 39.5 cm and Δy = 15.0 cm.
A= .150 Y= .395 m v= 3.0415 T= 0.1299 s
A wave traveling in the positive x-direction is pictured in Figure (a). Find the amplitude, wavelength, speed, and period of the wave if it has a frequency of 8.00 Hz. In Figure (a), Δx = 40.0 cm and Δy = 15.0 cm.
A= .150 Y= .400 m v= 3.20 m/s T= .125 s
A wave traveling in the positive x-direction is pictured in Figure (b). Find the amplitude, wavelength, speed, and period of the wave if it has a frequency of 17.0 Hz. In the figure, Δx = 63.5 cm and Δy = 25.0 cm.
A= .250 Y= .635 v=10.795 T= 0.0588 s
A wheel rotates with a constant angular acceleration of 3.50 rad/s2. If the angular speed of the wheel is 2.00 rad/s at t = 0, (a) through what angle does the wheel rotate between t = 0 and t = 2.00 s? Give your answer in radians and in revolutions. (b) What is the angular speed of the wheel at t = 2.00 s? (c) What angular displacement (in revolutions) results while the angular speed found in part (b) doubles?
A= 11.0 rad & 1.75 rev B=9.00 C=5.52 rev
A wheel rotates with a constant angular acceleration of 3.85 rad/s2. Assume the angular speed of the wheel is 1.50 rad/s at ti = 0. (a) Through what angle does the wheel rotate between t = 0 and t = 2.00 s? Give your answer in radians and revolutions. (b) What is the angular speed of the wheel at t = 2.00 s? (c) What angular displacement (in revolutions) results while the angular speed found in part (b) doubles?
A=10.7 RAD & 1.70 REV B=9.2 RAD/S C=5.25 REV
Suppose a 32.6-kg child sits 0.58 m to the left of center on the same seesaw as the problem you just solved in the PRACTICE IT section. A second child sits at the end on the opposite side, and the system is balanced. (a) Find the mass of the second child. (b) Find the normal force acting at the pivot point.
A=9.8 B= 544.43 N
Andrea and Chuck are riding on a merry-go-round. Andrea rides on a horse at the outer rim of the circular platform, twice as far from the center of the circular platform as Chuck, who rides on an inner horse. When the merry-go-round is rotating at a constant angular speed, Andrea's tangential speed is which of the following? A-impossible to determine B-twice Chuck's C-half of Chuck's D-the same as Chuck's
B
The two rigid objects shown in the figure below have the same mass, radius, and angular speed, each spinning around an axis through the center of its circular shape. If the same braking torque is applied to each, which takes longer to stop? B More information is needed. A
B
To make the wedge more effective in keeping the door closed, should it be placed closer to the hinge or to the doorknob? A-closer to the hinge B-closer to the doorknob
B
Suppose the radius of the wheel is doubled. Are the answers affected? If so, in what way? (Select all that apply.) A-The angle rotated through from t = 0 to t = 2.00 s is greater. B-The angular speed at t = 2.00 s is the same. C-The angular speed at t = 2.00 s is greater. D-The angle rotated through from t = 0 to t = 2.00 s is smaller. E-The angle rotated through from t = 0 to t = 2.00 s is the same. F-The angular speed at t = 2.00 s is smaller.
B & E
A constant net torque is applied to an object. Which one of the following will not be constant? A-center of gravity B-angular velocity C-angular acceleration D-moment of inertia
C
An object moves in a circular path with constant speed v. Which of the following statements is true concerning the object? A-Its acceleration is constant, but its velocity is changing. B-Its velocity and acceleration remain constant. C-Both its velocity and acceleration is changing. D-Its velocity is constant, but its acceleration is changing.
C
Andrea and Chuck are riding on a merry-go-round. Andrea rides on a horse at the outer rim of the circular platform, twice as far from the center of the circular platform as Chuck, who rides on an inner horse. When the merry-go-round is rotating at a constant angular speed, Andrea's angular speed is which of the following? A-impossible to determine B-half of Chuck's C-the same as Chuck's D-twice Chuck's
C
If the student suddenly releases the weights, how does his own angular momentum, rotational kinetic energy, and angular speed change? (Select all that apply.) A-His rotational angular speed decreases. B-His angular momentum increases. C-His rotational kinetic energy remains the same. D-His angular momentum remains the same. E-His rotational kinetic energy decreases. F-His rotational angular speed remains the same. G-His rotational kinetic energy increases. I-His angular momentum decreases. H-His rotational angular speed increases.
C, D, f
A block on the end of a spring is pulled to position x = A and released. Through what total distance does it travel in one full cycle of its motion? A-A/2 B-2A C-A D-4A
D
A planet has two moons with identical mass. Moon 1 is in a circular orbit of radius r. Moon 2 is in a circular orbit of radius 2r. The magnitude of the gravitational force exerted by the planet on Moon 2 is which of the following compared with the gravitational force exerted by the planet on Moon 1? A-the same B-half as large C-four times as large D-one-fourth as large E-twice as large
D
If the static friction coefficient were increased, the maximum safe speed would: A-increase or decrease, depending on the radius of the turn. B-remain the same. C-increase or decrease, depending on the whether it is a right turn or left turn. D-increase. E-decrease.
D
Suppose the car subsequently goes over a rise with the same radius of curvature and at the same speed as part (a). What is the normal force in this case? A-6mg B-2mg C-mg D-0
D
What would be the period of the same pendulum (from the PRACTICE IT section) on the Moon, where the acceleration of gravity is 1.62 m/s2? 74 swings 60 s .172 m
T= 2.047
A race car accelerates uniformly from a speed of 42.0 m/s to a speed of 61.5 m/s in 5.00 s while traveling clockwise around a circular track of radius 3.60 102 m. When the car reaches a speed of 50.0 m/s, find the following. (a) the magnitude of the centripetal acceleration (b) the angular speed (c) the magnitude of the tangential acceleration (d) the magnitude of the total acceleration
a- 6.94 m/s^2 b- 0.139 rad/s c- 3.9 m/s^2 d- 7.96 m/s^2
When an object moving in simple harmonic motion is at its maximum displacement from equilibrium, which of the following is at a maximum? acceleration kinetic energy velocity
acceleration
Two spheres, one hollow and one solid, are rotating with the same angular speed around an axis through their centers. Both spheres have the same mass and radius. Which sphere, if either, has the higher rotational kinetic energy? A-They have the same kinetic energy. B-The solid sphere does. C-The hollow sphere does.
c
The period of a simple pendulum is measured to be T on Earth. If the same pendulum were set in motion on the Moon, its period would be which of the following? equal to T less than T greater than T
greater
If the mass is doubled, is the magnitude of the acceleration of the system at any position doubled, halved, or unchanged?
halved
Using a screwdriver, you try to remove a screw from a piece of furniture, but can't get it to turn. To increase the chances of success, you should use a screwdriver that
has a wider handle
If global warming continues, it's likely that some ice from the polar ice caps of the Earth will melt and the water will be distributed closer to the Equator. If this occurs, the length of the day (one rotation) would do which of the following? remain the same decrease increase
increase
If the amplitude of a system moving in simple harmonic motion is doubled, which of the following quantities doesn't change? period maximum speed maximum acceleration total energy
period
A simple pendulum is suspended from the ceiling of a stationary elevator, and the period is measured. If the elevator moves with constant velocity, the period does which of the following? increase decrease remain the same If the elevator accelerates upward, the period does which of the following? increase decrease remain the same
remain the same decrease
A pendulum clock depends on the period of a pendulum to keep correct time. Suppose a pendulum clock is keeping correct time and then Dennis the Menace slides the bob of the pendulum downward on the oscillating rod. Does the clock run slow, fast, or correctly? correctly slow fast
slow
Does a simple pendulum of length 0.50 m have a larger or smaller frequency of vibration than a simple pendulum of length 1.0 m? Explain. (Select all that apply.)
smaller