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free/or 0.5$ |
| 55343 | According to Newton’s laws of motion (which will be studied in Chapter 4), a frictionless incline should provide an acceleration of down the incline. A student with a stopwatch finds that an object, starting from rest, slides down a 15.00-m very smooth incline in exactly 3.00 s. Is the incline frictionless? |
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| 55344 | (a) Which of the following represents the greatest speed: (1) 1 m/s, (2) 1 km/h, (3) 1 ft/s, or (4) 1 mit/h?
(b) Express the speed 15.0 m/s in mi/h. |
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| 55345 | (a) What volume in liters is a cube 20 cm on a side?
(b) If the cube is filled with water, what is the mass of the water? |
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| 55346 | A train on a straight, level track has an initial speed of 1.50 m/s2. A uniform acceleration of is applied while the train travels 200 m.
(a) What is the speed of the train at the end of this distance?
(b) How long did it take for the train to travel the 200 m? |
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| 55347 | A train normally travels at a uniform speed of 72 km/h on a long stretch of straight, level track. On a particular day, the train must make a 2.0-min stop at a station along this track. If the train decelerates at a uniform rate of 1.0 m/s2 and, after the stop, accelerates at a rate of 0.50 m/s2, how much time is lost because of stop-ping at the station? |
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| 55348 | A train makes a round trip on a straight, level track. The first half of the trip is 300 km and is traveled at a speed of 75 km/h. After a 0.50 h layover, the train returns the 300 km at a speed of 85 km/h. What is the train’s
(a) Average speed and
(b) Average velocity? |
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| 55349 | A tennis ball is dropped from a height of 10.0 m. It rebounds off the floor and comes up to a height of only 4.00 m on its first rebound. (Ignore the small amount of time the ball is in contact with the floor.)
(a) Determine the ball’s speed just before it hits the floor on the way down.
(b) Determine the ball’s speed as it leaves the floor on its way up to its first rebound height.
(c) How long is the ball in the air from the time it is dropped until the time it reaches its maximum height on the first rebound? |
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| 55350 | A Super Ball is dropped from a height of 4.00 m. Assuming the ball rebounds with 95% of its impact speed,
(a) The ball would bounce to (1) less than 95%, (2) equal to 95%, or (3) more than 95% of the initial height?
(b) How high will the ball go? |
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| 55351 | A submarine is submerged 175 fathoms below the surface. What is its depth in meters? (A fathom is an old nautical measurement equal to 2 yd.) |
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| 55352 | A student was 18 in. long when she was born. She is now 5 ft 6 in. tall and 20 years old. How many centimeters a year did she grow on average? |
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| 55353 | A student wants to determine the distance from the lakeshore to a small island (Fig. 1.23). He first draws a 50-m line parallel to the shore. Then, he goes to the ends of the line and measures the angles of the lines of sight from the island relative to the line he has drawn. The angles are 30° and 40°. How far is the island from the shore? |
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| 55354 | A student throws a ball vertically upward such that it travels 7.1 m to its maximum height. If the ball is caught at the initial height 2.4 s after being thrown,
(a) What is the ball’s average speed, and
(b) What is its average velocity? |
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| 55355 | A student runs 30 m east, 40 m north, and 50 m west.
(a) The magnitude of the student’s net displacement is (1) between 0 and 20 m, (2) between 20 m and 40 m, (3) between 40 m and 60 m.
(b) What is his net displacement? |
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| 55356 | A student drops a ball from the top of a tall building; the ball takes 2.8 s to reach the ground.
(a) What was the ball’s speed just before hitting the ground?
(b) What is the height of the building? |
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| 55357 | A student driving home for the holidays starts at 8: 00 AM to make the 675-km trip, practically all of which is on nonurban interstate highways. If she wants to arrive home no later than 3: 00 PM, what must be her minimum average speed? Will she have to exceed the speed limit? |
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| 55358 | A sports car can accelerate from 0 to in 3.9 s. What is the magnitude of the average acceleration of the car in meters per second squared? |
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| 55359 | A spherical shell is formed by taking a solid sphere of radius 20.0 cm and hollowing out a spherical section from the shell’s interior. Assume the hollow section and the sphere itself have the same center location (that is, they are concentric).
(a) If the hollow section takes up 90.0 percent of the total volume, what is its radius?
(b) What is the ratio of the outer area to the inner area of the shell? |
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| 55360 | (a) Show that the area under the curve of a velocity-versus-time plot for a constant acceleration is equal to the displacement.
(b) Compute the distance traveled for the motion represented by Fig. 2.23. |
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| 55361 | A senior citizen walks 0.30 km in 10 min, going around a shopping mall.
(a) What is her average speed in meters per second?
(b) If she wants to increase her average speed by 20 % when walking a second lap, what would her travel time in minutes have to be? |
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| 55362 | A roller coaster car traveling at a constant speed of 20.0 m/s on a level track comes to a straight incline with a constant slope. While going up the incline, the car has a constant acceleration of 0.750 m/s2 in magnitude.
(a) What is the speed of the car at 10.0 s on the incline?
(b) How far has the car traveled up the incline at this time? |
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