| № |
Condition |
free/or 0.5$ |
| 55323 | Driving a jet- powered car, Royal Air Force pilot Andy Green broke the sound barrier on land for the first time and achieved a record land speed of more than in Black Rock Desert, Nevada, on October 15, 1997 (Fig. 1.15).
(a) What is this speed expressed in m/s?
(b) How long would it take the jet- powered car to travel the length of a 300- ft football field at this speed? |
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| 55324 | Determine the number of significant figures in the following measured numbers:
(a) 1.007 m,
(b) 8.03 cm,
(c) 16.272 kg,
(d) 0.015 μs (microseconds). |
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| 55325 | Convert the following:
(a) 40 000 000 bytes to MB,
(b) 0.5722 mL to L,
(c) 2.684 m to cm,
(d) 5 500 bucks to kilobucks. |
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| 55326 | Car A is in a straight- line distance d from a starting line, and Car B is a distance of 2 d from the line. Accelerating uniformly from rest, it is desired that both cars cross the starting line at the same speed. If so, which car has the greater acceleration, and how much greater? |
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| 55327 | At the Indianapolis 500 time trials, each car makes four consecutive laps, with its overall or average speed determining that car’s place on race day. Each lap covers 2.5 mi (exact). During a practice run, cautiously and gradually taking his car faster and faster, a driver records the following average speeds for each successive lap: 160 mi/h, 180 mi/h, 200 mi/h, and 220 mi/h.
(a) Will his average speed be (1) exactly the average of these speeds (190 mi/h), (2) greater than 180 mi/h, or (3) less than 180 mi/h? Explain.
(b) To corroborate your conceptual reasoning, calculate the car’s average speed. |
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| 55328 | At a sports car rally, a car starting from rest accelerates uniformly at a rate of 9.0 m/s2 over a straight-line distance of 100 m. The time to beat in this event is 4.5 s. Does the driver beat this time? If not, what must the minimum acceleration be to do so? |
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| 55329 | Assuming a reaction time of 0.50 s for the driver in Exercise 48, will the car stop before hitting the child? |
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| 55330 | Approximately 118 mi wide, 307 mi long, and aver-aging 279 ft in depth, Lake Michigan is the second-largest Great Lake by volume. Estimate its volume of water in cubic meters. |
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| 55331 | Anew-car owner wants to show a friend how fast her sports car is. The friend gets in his car and drives down a straight, level highway at a constant speed of 60 km/h to a point where the sports car is waiting. As the friend’s car just passes, the sports car accelerates at a rate of 2.0 m/s2.
(a) How long does it take for the sports car to catch up to the friend’s car?
(b) How far down the road does the sports car catch up to the friend’s car?
(c) How fast is the sports car going at this time? |
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| 55332 | An Olympic sprinter can run 100 yd in 9.0 s. At the same rate, how long would it take the sprinter to run 100 m? |
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| 55333 | An object moves in the + x-direction at a speed of 40 m/s. As it passes through the origin, it starts to experience a constant acceleration of 3.5 m/s2 in the – x-direction.
(a) What will happen next? (1) The object will reverse its direction of travel at the origin; (2) the object will keep traveling in the + x-direction; (3) the object will travel in the + x-direction and then reverses its direction. Why?
(b) How much time elapses before the object returns to the origin?
(c) What is the velocity of the object when it returns to the origin? |
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| 55334 | An object initially at rest experiences an acceleration of on a level surface. Under these conditions, it travels 6.00 m. Let’s designate the first 3.00 m as phase 1 with a subscript of 1 for those quantities, and the second 3.00 m as phase 2 with a subscript of 2.
(a) The times for traveling each phase should be related by which condition: (1) t1 < t2, (2) t1 = t2, or (3) t1 > t2?
(b) Now calculate the two travel times and compare them quantitatively. |
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| 55335 | An object initially at rest experiences an acceleration of 1.5 m/s2 for 6.0 s and then travels at that constant velocity for another 8.0 s. What is the object’s average velocity over the 14-s interval? |
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| 55336 | An insect crawls along the edge of a rectangular swimming pool of length 27 m and width 21 m (Fig. 2.19). If it crawls from corner A to corner B in 30 min,
(a) What is its average speed, and
(b) What is the magnitude of its average velocity? |
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| 55337 | An automobile traveling at 15.0 km/h along a straight, level road accelerates to 65.0 km/h in 6.00 s. What is the magnitude of the auto’s average acceleration? |
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| 55338 | An automobile speedometer is shown in Fig. 1.16.
(a) What would be the equivalent scale readings (for each empty box) in kilometers per hour?
(b) What would be the 70- mi/h speed limit in kilometers per hour? |
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| 55339 | An automobile is traveling on a long, straight high-way at a steady 75.0 mi/h when the driver sees a wreck 150 m ahead. At that instant, she applies the brakes (ignore reaction time). Between her and the wreck are two different surfaces. First there is 100 m of ice, where the deceleration is only 1.00 m/s2. From then on, it is dry concrete, where the deceleration is a more normal 7.00 m/s2.
(a) What was the car’s speed just after leaving the icy portion of the road?
(b) What is the total distance her car travels before it comes to a stop?
(c) What is the total time it took the car to stop? |
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| 55340 | After landing, a jetliner on a straight runway taxis to a stop at an average velocity of – 35.0 km/h. If the plane takes 7.00 s to come to rest, what are the plane’s initial velocity and acceleration? |
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| 55341 | Acorner construction lot has the shape of a right triangle. If the two sides perpendicular to each other are 37 m long and 42.3 m long, what is the length of the hypotenuse? |
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| 55342 | Acord of wood is a volume of cut wood equal to a stack 8.0 ft long, 4.0 ft wide, and 4.0 ft high. How many cords are there in 3.0 m3? |
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