Pregunta 1
Pregunta
Perform the following operation and express your answer using the appropriate number of significant figures:
8.75 ms − 750.0 μs (in ms)
Respuesta
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8.00 ms
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1.25 ms
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15.5 ms
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9.50 ms
Pregunta 2
Pregunta
Perform the following unit conversion and express your answer in scientific notation.
0.00480 mm → μm
Respuesta
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4.80 μm
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4.80 x 10^2 μm
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4.80 x 10^1 μm
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4.80 x 10^-6 μm
Pregunta 3
Pregunta
A fireworks shell is accelerated from rest to a velocity of65.0 m/s over a distance of 0.250 m. How long did the acceleration last?
Respuesta
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130 s
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7.69 x 10^-2 s
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3.85 x 10^-3 s
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7.69 x 10^-3 s
Pregunta 4
Pregunta
A swimmer bounces straight up from a diving board and falls feet first into a pool. She starts with a velocity of 4.00 m/s, and her takeoff point is 1.80 m above the pool. What is her velocity when her feet hit the water?
Respuesta
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0.816 m/s
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1.14 m/s
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-7.16 m/s
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7.16 m/s
Pregunta 5
Pregunta
A steel ball is dropped onto a hard floor from a height of 1.50 m and rebounds to a height of 1.45 m. Its contact with the floor lasts 0.0800 ms (8. 00 × 10^−5 s). How much did the ball compress during its collision with the floor, assuming the floor is absolutely rigid?
Respuesta
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-1.34 x 10^-2 m
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-5.33 x 10^-3 m
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-3.73 x 10^-6 m
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5.33 x 10^-6 m
Pregunta 6
Pregunta
A ferry leaves the terminal and travels 124 km in a direction 12.0 degrees north of west to island A. After a short stop, the ferry travels 85.4 km in a direction 26.0 degrees west of south to island B. The ferry then completes the round trip by returning directly to the terminal.
What is the displacement (magnitude and direction) of the ferry in the last trip?
Respuesta
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139 km, 50.7 degrees south of west
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139 km, 50.7 degrees north of east
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167 km, 17.8 degrees south of west
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167 km, 17.8 degrees north of east
Pregunta 7
Pregunta
A section of a river is 252 m wide and the water flows east with a uniform velocity of 1.10 m/s. A boat starts at point A on the south bank and crosses the river to point B on the opposite side. If the trip takes 3.00 min, find the velocity of the boat with respect to a stationary observer on the ground.
Respuesta
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1.4 m/s
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1.78 m/s
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1.10 m/s
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0.3 m/s
Pregunta 8
Pregunta
Three vectors A, B, and C each has a magnitude of 40.0 units. Their directions relative to the positive x axis are 30.0 degrees, 90.0 degrees, and 120 degrees.
Find the magnitude and velocity of 2(A + C) − 3B.
Respuesta
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6.86 units, 165 degrees
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31.2 units, 20.1 degrees
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40 units, 90 degrees
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13 units, 16 degrees
Pregunta 9
Pregunta
While rolling along a flat terrain at 48.0 km/h, a military tank fires its main cannon at 30.0 degrees above the horizontal. The shell leaves the barrel with muzzle velocity of 480 m/s
relative to the moving tank. Neglect air resistance and the height of the barrel above the ground. Do not neglect the speed of the tank. How long does it take the tank to arrive at the target hit by the shell?
Respuesta
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0.438 h
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15.7 h
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3.38 h
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0.111 h
Pregunta 10
Pregunta
A 65.0 kg box is pushed up a ramp inclined at 27.0 degrees. The applied force (F) is horizontal and causes the box to move at a constant speed. Determine the magnitude of the applied force when the coefficient of kinetic friction is 0.200.
Pregunta 11
Pregunta
A large rocket has a mass of 2.00 x10^6 kg at takeoff, and its engines produce a thrust of 3.50 × 10^7 N. Find its initial acceleration if it takes off vertically.
Respuesta
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7.20 m/s^2
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7.70 m/s^2
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17.5 m/s^2
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9.80 m/s^2
Pregunta 12
Pregunta
A 4.00 kg block slides on the surface of an inclined table, which makes an angle of 15.0 degrees with the horizontal. The block is connected through cords over two pulleys to a 7.26 kg bowling ball on the upper side of the table, and a 3.00 kg ball on the lower side. The pulleys are mass-less and friction-less, while the coefficient of kinetic friction between the block and the table's is 0.470. The acceleration of the system is 0.968 m/s^2.
Calculate the tension in each cord.
Respuesta
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7.04 N, 2.91 N
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64.1 N, 32.3 N
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71.1 N, 29.4 N
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68.7 N, 7.61 N
Pregunta 13
Pregunta
The tightrope walker creates a tension of 3.94 × 10^3 N in a wire making an angle 5.0 degrees below the horizontal with each supporting pole. Calculate how much this tension stretches the steel wire if it was originally 15 m long and 0.50 cm in diameter. The Young's modulus for steel is 210 x 10^9 N/m^2.
Respuesta
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2.8 cm
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2.5 cm
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1.4 cm
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3.94 cm
Pregunta 14
Pregunta
A farmer making grape juice fills a glass bottle to the brim and caps it tightly. The juice expands more than the glass when it warms up, in such a way that the volume increases by 0.2% (that is, ΔV / V0 = 2 × 10^−3) relative to the space available. Calculate the magnitude of the normal force exerted by the juice per square centimeter if its bulk modulus is 1.8 × 10^9 N/m^2, assuming the bottle does not break.
Respuesta
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360 N/cm^2
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180 N/cm^2
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200 N/cm^2
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720 N/cm^2
Pregunta 15
Pregunta
If a bobsled turns on a ideally banked curve at 75.0 degrees and taken at 30.0 m/s, what is its centripetal acceleration?
Respuesta
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1.22 m/s^2
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24.6 m/s^2
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36.6 m/s^2
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37.5 m/s^2
Pregunta 16
Pregunta
Calculate the ideal speed to take a 100 m radius curve banked at 15.0 degrees.
Respuesta
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16.2 km/h
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58.3 km/h
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30.8 km/h
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8.55 km/h
Pregunta 17
Pregunta
What is the speed of the roller coaster at the top of the loop if the radius of curvature there is 15.0 m and the downward acceleration of the car is 1.50 g?
Respuesta
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14.8 m/s
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4.74 m/s
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7.40 m/s
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22.5 m/s
Pregunta 18
Pregunta
What is the kinetic energy of a 20,000-kg truck moving at 110 km/h and an 80.0-kg astronaut in orbit moving at 27,500 km/h.
Respuesta
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9.36 x 10^6 J, 2.33 x 10^9 J
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3.06 x 10^5 J, 1.10 x 10^6 J
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9.36 x 10^6 J, 3.03 x 10^10 J
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3.06 x 10^5 J, 2.33 x 10^9 J
Pregunta 19
Pregunta
A swimmer exerts an average horizontal backward force of 80.0 N with his arm during each 1.80 m long stroke. Calculate the power output of his arms if he does 120 strokes per minute
Respuesta
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2.4 W
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288 W
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120 W
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1.728 x 10^4 W
Pregunta 20
Pregunta
When serving a tennis ball, a player hits the ball when its velocity is zero (at the highest point of a vertical toss). The racquet exerts a force of 540 N on the ball for 5.00 ms, giving it a final velocity of 45.0 m/s. Find the mass of the ball.
Respuesta
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0.03 kg
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12 kg
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0.06 kg
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2.4 kg
Pregunta 21
Pregunta
Two identical pucks collide on an air hockey table. One puck was originally at rest. If the incoming puck has a speed of 6.00 m/s and scatters to an angle of 30.0 degrees, what is the velocity (magnitude and direction) of the second puck? (You may use the result that θ1 − θ2 = 90 degrees for elastic collisions of objects that have identical masses.)
Respuesta
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2.50 m/s
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3.00 m/s
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0 m/s
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9.00 m/s
Pregunta 22
Pregunta
A glass of water (height 15 cm and diameter 7.0 cm) sits on a dining table. The coefficient of static friction between the glass and the table's surface is 0.35. Determine the maximum height (h) above the tabletop at which you can push horizontally, with your fingertip, and cause the glass to slide without tipping.
Pregunta 23
Pregunta
A 160-kg utility pole extends 12.0 m above the ground. A horizontal force of 250 N acts at its top and the pole is held in the vertical position by a cable. Determine the tension in the cable.
Respuesta
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1830 N
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125 N
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458 N
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1568 N
Pregunta 24
Pregunta
What is the general formula for the acceleration of a solid sphere rolling down an inclined surface?
Respuesta
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a = 5/7 g sinθ
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a = 1/2 g sinθ
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a = 2/3 g sinθ
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a = 3/5 g sinθ
Pregunta 25
Pregunta
A wagon wheel is constructed, where the mass of the rim is 2.80 kg and each of the eight spokes has a mass of 0.400 kg. If the diameter of the wheel is 91.0 cm, its moment of inertia is equal to
Respuesta
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0.607 kg x m^2
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0.400 kg x m^2
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1.24 kg x m^2
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0.800 kg x m^2