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free/or 0.5$ |
| 55303 | In a radioactivity experiment, a solid lead brick (with same measurements as a patio brick, 2.00 in. X 4.00 in. X 8.00 in, except with a density that is 11.4 times that of water) is to be modified to hold a solid cylindrical piece of plastic. To accomplish this, the machinists are told to drill a cylindrical hole 2.0 cm in diameter through the center of the brick parallel to the longest side of the brick.
(a) What is the mass of lead (in kilograms) removed from the brick?
(b) What percentage of the original lead remains in the brick?
(c) Assuming the cylindrical hole is completely filled with plastic (with a density twice that of water), determine the overall (aver-age) density of the combination after fabrication is complete. |
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| 55304 | If the instantaneous velocity of an object is zero, is the acceleration necessarily zero? |
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| 55305 | If the displacement of an object is 300 m north, what can you say about the distance traveled by the object? |
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| 55306 | If the components of the human circulatory system (arteries, veins, and capillaries) were completely extended and placed end to end, the length would be on the order of 100 000 km. Would the length of the circulatory system reach around the circumference of the Moon? If so, how many times? |
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| 55307 | If the capillaries of an average adult were unwound and spread out end to end, they would extend to a length over 40 000 mi (Fig. 1.9). If you are 1.75 m tall, how many times your height would the capillary length equal? |
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| 55308 | If a fellow student tells you he saw a 3-cm-long ladybug, would you believe him? How about another student saying she caught a 10kg salmon? |
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| 55309 | Human adult blood contains, on average, 7000/mm3 white blood cells (leukocytes) and 250 000/mm3 platelets (thrombocytes). If a person has a blood volume of 5.0 L, estimate the total number of white cells and platelets in the blood. |
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| 55310 | How would free fall on the Moon differ from that on the Earth? |
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| 55311 | How many variables must be known to solve a kinematic equation? |
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| 55312 | How many minutes of arc does the Earth rotate in 1 min of time? |
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| 55313 | For the motion of a dropped object in free fall, sketch the general forms of the graphs of
(a) v versus t and
(b) y versus t. |
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| 55314 | Figure 2.24 shows a plot of velocity versus time for an object in linear motion.
(a) What are the instantaneous velocities at t = 8.0 s and t = 11.0 s?
(b) Compute the final displacement of the object.
(c) Compute the total distance the object travels. |
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| 55315 | Figure 2.24 shows a plot of velocity versus time for an object in linear motion.
(a) Compute the acceleration for each phase of motion.
(b) Describe how the object moves during the last time segment. |
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| 55316 | Fig. 1.18 is a picture of red blood cells seen under a scanning electron microscope. Normally, women possess about 4.5 million of these cells in each cubic millimeter of blood. If the blood flow to the heart is 250mL/min, how many red blood cells does a woman’s heart receive each second? |
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| 55317 | Express the length 50 500 μm (micrometers) in centimeters, decimeters, and meters, to three significant figures. |
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| 55318 | Express the following calculations using the proper number of significant figures:
(a) 12.634 + 2.1,
(b) 13.5 – 2.134,
(c) π(0.25 m)2,
(d) √2.37/3.5 |
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| 55319 | Express each of the numbers in Exercise 43 with two significant figures.
(a) 1.007 m,
(b) 8.03 cm,
(c) 16.272 kg,
(d) 0.015 μs (microseconds). |
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| 55320 | Explain why a metric ton is equivalent to 1000 kg. |
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| 55321 | Einstein’s famous mass– energy equivalence is expressed by the equation E = mc2, where E is energy, m is mass, and c is the speed of light.
(a) What are the SI base units of energy?
(b) Another equation for energy is E = mgh, where m is mass, g is the acceleration due to gravity, and h is height. Does this equation give the same units as in part (a)? |
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| 55322 | During liftoff, a hot-air balloon accelerates upward at a rate of 3.0 m/s2. The balloonist drops an object over the side of the gondola when the speed is 15 m/s.
(a) What is the object’s acceleration after it is released (relative to the ground)?
(b) How long does it take to hit the ground? |
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