5. Sean is running a 100m dash. When the starter's pistol fires, he leaves the starting block and continues speeding up until 7 s into the race, when he reaches his top speed of 11 m/s. He holds this speed for 2s; then his speed has slowed to 10 m/s by the time he crosses the finish line 11 s after he starts the race. a. What was Sean's average acceleration during the first 7 s of the race? b. What was Sean's average acceleration from 7 to 9 s into the race? What was Sean's average acceleration from 9 to 11 s into the race? c.

5. Sean is running a 100m dash. When the starter's pistol fires, he leaves the starting block and continues speeding up until 7 s into the race, when he reaches his top speed of 11 m/s. He holds this speed for 2s; then his speed has slowed to 10 m/s by the time he crosses the finish line 11 s after he starts the race. a. What was Sean's average acceleration during the first 7 s of the race? b. What was Sean's average acceleration from 7 to 9 s into the race? What was Sean's average acceleration from 9 to 11 s into the race? c.

Physics for Scientists and Engineers with Modern Physics

10th Edition

ISBN:9781337553292

Author:Raymond A. Serway, John W. Jewett

Publisher:Raymond A. Serway, John W. Jewett

Chapter2: Motion In One Dimension

Section: Chapter Questions

Problem 7P: A person takes a trip, driving with a constant speed of 89.5 km/h, except for a 22.0-min rest stop....

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A person takes a trip, driving with a constant speed of 89.5 km/h, except for a 22.0-min rest stop. If the persons average speed is 77.8 km/h, (a) how much time is spent on the trip and (b) how far does the person travel?
A motorist drives for 35.0 minutes at 85.0 km/h and then stops for 15.0 minutes. He then continues north, traveling 130. Km in 2.00 h. (a) What is his total displacement? (b) What is his average velocity?
A motorist drives for 35.0 minutes at 85.0 km/h and then stops for 15.0 minutes. He then continues north, traveling 130. Km in 2.00 h. (a) What is his total displacement? (b) What is his average velocity?
A commuter backs her car out of her garage with an acceleration of 1.40 m/s2. (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?
(a) Explain how you can determine the acceleration over time from a velocity versus time graph such as the one in Figure 2.56. (b) Based on the graph, how does acceleration change over time?
1).A car accelerates from rest until it is traveling at 88km/hr. The time to keep up to speed is 6.2 sec. What is the acceleration of the car in m/s2 ? How far t=did the car travel in 6.2 secs in meters? 2). A rock is dropped from rest and free falss at 10m/s. How fast will the rock be moving right before it hits the ground it it falls 3.3m? HOw long dies it take for the rock to fall 3.3m? 3). A rock is thrown upwar and reached a height of 12m. How fast was the rock thrown? How long does it take for the rock to reach its max height? 4) A family road trip starts out in a van travelling 50km at a velocity of 75km/ hr followed by a spot of slow traffic where they travel 10km at a velocity of 25km/hr. What is the average velocity during the trip km/hr? 5) A car moves with velocity of 60km/hr for 45 min. The driver takes a 15min break at a gas station before travelling at 70kmm/hr for 30min. What was the average velocity of the car over the total trip in km/hr?
A sprinter is running at a speed of 10.0 m/s, then accelerates at a constant rat e of 2.86 m/s2 for the last 8.50 m of the race. What is his final speed as he crosses the finish line?How long did it take him to run the last 8.50 m of the race?
2). Starting for rest, Usain Bolt crossed the finish line of a 100 m race with a speed of 10.44 m/s, a. calculate his acceleration? b. how long did he take to complete the 100 m race?
A cheetah can accelerate from rest to a speed of 30.0 m/s in 7.00 s. What is it's acceleration? A commuter backs her car out of her garage with an acceleration of 1.40 mis2. (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?
A rocket accelerates from rest at a rate of 58 m/s2. (a) What is its speed after it accelerates for 41 s? ________________________m/s(b) How long does it take for the rocket to reach a speed of 7,700 m/s?___________________________ s
A rocket accelerates from rest at a rate of 70 m/s2. (a) What is its speed after it accelerates for 53 s? m/s (b) How long does it take for the rocket to reach a speed of 6,700 m/s? s
2. A subway train starts from rest at a station and accelerates at a rate of 2.50 m/s2 for15.90 seconds. It then runs at a constant speed for 35 seconds and then slows down ata rate of 4.50 m/s2 until it stops at the next station.(a) What is the speed of the train just before it starts slowing down?(Ans.: = 39.75 m/s)(b) How long did it take the train to finish the trip from one station to the other?(Ans.: = 59.73 s)