Solution a g 576 576 ms 98 ms 564 ms 564 s 500 ms ms 282 2 2 2 a g a t v v a b

# Solution a g 576 576 ms 98 ms 564 ms 564 s 500 ms ms

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Solution (a) g 5.76 5.76 m/s 9.8 m/s 56.4 m/s 56.4 s 5.00 m/s 0 m/s 282 2 2 2 0 a g a t v v a (b) g 6 . 20 55 . 20 m/s 9.8 m/s 201 m/s 201 s 1.40 m/s 282 m/s 0 2 2 2 0 a g a t v' v' a' 18. A commuter backs her car out of her garage with an acceleration of 2 m/s 1.40 . (a) How long does it take her to reach a speed of 2.00 m/s? (b) If she then brakes to a stop in 0.800 s, what is her deceleration? Solution (a) s 1.43 m/s 1.40 m/s 0 m/s 2.00 2 0 a v v t (b) 2 0 m/s 2.50 s 0.800 m/s 2.00 m/s 0 t v v a
OpenStax College Physics Instructor Solutions Manual Chapter 2 19. Assume that an intercontinental ballistic missile goes from rest to a suborbital speed of 6.50 km/s in 60.0 s (the actual speed and time are classified). What is its average acceleration in 2 m/s and in multiples of g ) m/s (9.80 2 ? Solution g 11.1 m/s 9.8 m/s 108 m/s 108 s 60.0 m/s 0 m/s 10 6.50 2 2 2 3 0 a g a t v v a
OpenStax College Physics Instructor Solutions Manual Chapter 2 2.5 MOTION EQUATIONS FOR CONSTANT ACCELERATION IN ONE DIMENSION 20. An Olympic-class sprinter starts a race with an acceleration of 2 m/s 4.50 . (a) What is her speed 2.40 s later? (b) Sketch a graph of her position vs. time for this period. Solution (a) m/s 8 . 10 ) s 40 . 2 )( m/s 50 . 4 ( m/s 0 2 0 at v v (b) Assuming the acceleration is constant, we know 2 2 2.25 (½) t at x . We can create a graph by plugging in a few different t -values, say t = 1, 2, 3, 4, 5: Time (s) Position (m) 0 0 1 2.25 2 9 3 20.25 4 36 5 56.25
OpenStax College Physics Instructor Solutions Manual Chapter 2 21. A well-thrown ball is caught in a well-padded mitt. If the deceleration of the ball is 2 4 m/s 10 10 . 2 , and 1.85 ms s) 10 ms (1 3 elapses from the time the ball first touches the mitt until it stops, what was the initial velocity of the ball? Solution m/s 38.9 s) 10 )(1.85 m/s 10 2.10 ( m/s 0 3 2 4 0 at v v (about 87 miles per hour) 22. A bullet in a gun is accelerated from the firing chamber to the end of the barrel at an average rate of 2 5 m/s 10 6.20 for s 10 8.10 4 . What is its muzzle velocity (that is, its final velocity)? Solution m/s 502 s) 10 )(8.10 m/s 10 (6.20 m/s 0 4 2 5 0 at v v 23. (a) A light-rail commuter train accelerates at a rate of 2 m/s 1.35 . How long does it take to reach its top speed of 80.0 km/h, starting from rest? (b) The same train ordinarily decelerates at a rate of 2 m/s 1.65 . How long does it take to come to a stop from its top speed? (c) In emergencies the train can decelerate more rapidly, coming to rest from 80.0 km/h in 8.30 s. What is its emergency deceleration in 2 m/s ? Solution (a) (b)
OpenStax College Physics Instructor Solutions Manual Chapter 2 (c) 2 0 m/s 2.68 km 1 m 1000 s 3600 h 1 s 8.30 km/h 80.0 km/h 0 t v v a 24. While entering a freeway, a car accelerates from rest at a rate of 2 m/s 2.40 for 12.0 s. (a) Draw a sketch of the situation. (b) List the knowns in this problem. (c) How far does the car travel in those 12.0 s? To solve this part, first identify the unknown, and then discuss how you chose the appropriate equation to solve for it. After choosing
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