Pregunta 1
Pregunta
The length and width of a rectangular room are measured to be 3.955 ± 0.005 m and 3.050 ± 0.005 m. Calculate the area of the room and its uncertainty in square meters.
Respuesta
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12.06 ± 0.04 m^2
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13.00 ± 0.04 m^2
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12.06 ± 0.000025 m^2
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12.06 ± 0.01 m^2
Pregunta 2
Pregunta
A car engine moves a piston with a circular cross section of 7.500 ± 0.002 cm diameter a distance of 3.250 ± 0.001 cm to compress the gas in the cylinder. (a) By what amount is the gas decreased in volume in cubic centimeters? (b) Find the uncertainty in this volume.
Respuesta
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38.29 ± 0.003 cm^3
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143.6 ± 0.1 cm^3
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143.6 ± 0.08 cm^3
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143.6 ± 0.2 cm^3
Pregunta 3
Pregunta
If the swan must reach a velocity of 6.00 m/s to take off and it accelerates from rest at an average rate of 0.350 m/s^2, how far will it travel before becoming airborne?
Respuesta
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103 m
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12.9 m
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51.4 m
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3.67 m
Pregunta 4
Pregunta
Blood is accelerated from rest to 30.0 cm/s in a distance of 1.80 cm by the left ventricle of the heart. How long does the acceleration take?
Respuesta
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0.12 s
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0.06 s
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250 s
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0.20 s
Pregunta 5
Pregunta
Suppose a pilot flies 40.0 km in a direction 60 degrees north of east and then flies 30.0 km in a direction 15 degrees north of east. Find her total distance R from the starting point and the direction θ of the straight-line path to the final position.
Respuesta
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28.3 km, 83.6 degrees
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64.8 km, 40.9 degrees
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64,8 km, 49.1 degrees
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70.0 km, 50 degrees
Pregunta 6
Pregunta
The velocity of the wind relative to the water is crucial to sailboats. Suppose a sailboat is in an ocean current that has a velocity of 2.20 m/s in a direction 30.0 degrees east of north relative to the Earth. It encounters a wind that has a velocity of 4.50 m/s in a direction of 50.0 degrees south of west relative to the Earth. What is the velocity of the wind relative to the water?
Respuesta
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6.68 m/s, 53.3 degrees south of west
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6.68 m/s, 53.3 degrees north of east
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2.36 m/s, 25.7 degrees south of west
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6.61 m/s, 46.5 degrees south of west
Pregunta 7
Pregunta
A hot-air balloon descends toward the ground at constant velocity. The net force on the balloon is
Respuesta
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greater than its weight and directed downward
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smaller than its weight and directed upward
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equal to 0
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equal to its weight and directed downward
Pregunta 8
Pregunta
76.0-kg person is being pulled away from a burning building. Calculate the tension in the two ropes if the person is momentarily motionless.
Respuesta
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736 N, 194 N
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244 N, 928 N
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656 N, 118 N
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800 N, 200 N
Pregunta 9
Pregunta
Two muscles in the back of the leg pull upward on the Achilles tendon. Find the magnitude and direction of the total force on the Achilles tendon.
Pregunta 10
Pregunta
A baseball falls from the top of a skyscraper. When the ball reaches half its terminal speed, its acceleration is equal to
Respuesta
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9.80 m/s^2
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2.45 m/s^2
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7.35 m/s^2
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3.27 m/s^2
Pregunta 11
Pregunta
A block of mass m falls down pulling an identical block on a 20 degree-incline. The coefficient of kinetic friction between the second block and the inclined surface is 0.44. Neglect the mass of the string and assume the pulley is light and friction-less. The acceleration of the system is equal to
Respuesta
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2.4 m/s^2
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1.2 m/s^2
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2.9 m/s^2
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3.2 m/^2
Pregunta 12
Pregunta
A ping pong ball, of mass 2.7g and diameter 4.0cm, is dropped from a 15-m high building. Estimate the ball's terminal velocity. The drag coefficient for a sphere is 0.45. and the density of air is 1.21 kg/m^3.
Respuesta
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4.40 m/s
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8.79 m/s
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3.12 m/s
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9.83 m/s
Pregunta 13
Pregunta
A 20.0m tall hollow aluminum flagpole is equivalent in strength to a solid cylinder 4.00 cm in diameter. The pole bends when a strong wind exerts a horizontal force of 900 N at the top. How far to the side does the top of the pole flex? The shear modulus of aluminum is S = 25.0 x 10^9 N/m^2.
Respuesta
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0.573 mm
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0.143 mm
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0.01 mm
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5.73 x 10^5 mm
Pregunta 14
Pregunta
Find the mass of Jupiter. The orbital radius of Io (one of Jupiter's moons) is 4.22 x 10^5 km and it makes one revolution every 1.77 days.
Respuesta
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4.50 x 10^12 kg
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5.97 x 10^24 kg
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1.90 x 10^27 kg
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4.63 x 10^22 kg
Pregunta 15
Pregunta
A 22.0 kg child is riding a playground merry-go-round that is rotating at 40.0 rev/min. What centripetal force must she exert to stay on if she is 1.25 m from its center?
Respuesta
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2.82 x 10^4 N
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483 N
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308 N
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880 N
Pregunta 16
Pregunta
How much work is done by the boy pulling his sister 30.0 m in a wagon? Assume no friction acts on the wagon.
Respuesta
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1500 J
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750 J
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1300 J
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550 J
Pregunta 17
Pregunta
A pogo stick has a spring with a force constant of 2.50 × 10^4 N/m, which can be compressed 12.0 cm. To what maximum height can a child jump on the stick using only the energy in the spring, if the child and stick have a total mass of 40.0 kg?
Respuesta
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0.459 m
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3.83 m
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0.115 m
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0.626 m
Pregunta 18
Pregunta
What is the average useful power output of a person who does 6.00 × 10^6 J of useful work in 8.00 h?
Pregunta 19
Pregunta
What is the average force exerted on a 0.0300-kg bullet to accelerate it to a speed of 600 m/s in a time of 2.00 ms (milliseconds)?
Respuesta
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900 N
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90000 N
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9000 N
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18000 N
Pregunta 20
Pregunta
Train cars are coupled together by being bumped into one another. Suppose two loaded train cars are moving toward one another, the first having a mass of 150,000 kg and a velocity of 0.300 m/s, and the second having a mass of 110,000 kg and a velocity of −0.120 m/s. What is their final velocity?
Respuesta
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0.224 m/s
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0.336 m/s
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-0.122 m/s
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0.122 m/s
Pregunta 21
Pregunta
To get up onto the roof, a person (mass 74.0 kg) places a 20.0-ft uniform aluminum ladder (mass 13.0 kg) against the building, where the wall is covered by smooth vinyl siding. The base of the ladder is 6.00 ft from the building. When the person is standing 6.70ft from the top end of the ladder, determine the force exerted by the wall at the top end.
Pregunta 22
Pregunta
A 75-kg man stands on his toes by exerting an upward force through the Achilles tendon. What is the force in the Achilles tendon if he stands on one foot?
Respuesta
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2205 N
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4410 N
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441 N
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1100 N
Pregunta 23
Pregunta
Consider a 12.0 kg motorcycle wheel with an inner radius of 0.280 m and an outer radius of 0.330 m. If the drive chain exerts a force of 2200 N at a radius of 5.00 cm, what is the angular acceleration of the wheel?
Respuesta
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7.33 rad/s^2
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14.7 rad/s^2
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97.9 rad/s^2
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32.2 rad/s^2
Pregunta 24
Pregunta
A solid cylinder of mass 60.0 kg and diameter 60.0 cm rotates about its axis at initial angular velocity of 700 rpm. When an external torque is applied for 15.7 s, the angular velocity of the cylinder reaches 850 rpm. Assume no thermal energy is generated. Determine the torque applied.
Respuesta
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2.70 kg x m^2
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21.6 kg x m^2
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14.4 kg x m^2
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10.8 kg x m^2
Pregunta 25
Pregunta
Three children are riding on the edge of a merry-go-round that is 100 kg, has a 1.60-m radius, and is spinning at 20.0 rpm. The children have masses of 22.0, 28.0, and 33.0 kg. If the child who has a mass of 28.0 kg moves to the center of the merry-go-round, what is the new angular velocity in rpm?
Respuesta
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268.8 rpm
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25.3 rpm
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340.5 rpm
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134.4 rpm