GO You are arguing over a cell phone while trailing an unmarked police car by 25 m; both your car and the police car are traveling at 110 km/h. Your argument diverts your attention from the police car for 2.0 s (long enough for you to look at the phone and yell, “I won’t do that!”). At the beginning of that 2.0 s, the police officer begins braking suddenly at 5.0 m/s 2 . (a) What is the separation between the two cars when your attention finally returns? Suppose that you take another 0.40 s to realize your danger and begin braking. (b) If you too brake at 5.0 m/s 2 , what is your speed when you hit the police car?
GO You are arguing over a cell phone while trailing an unmarked police car by 25 m; both your car and the police car are traveling at 110 km/h. Your argument diverts your attention from the police car for 2.0 s (long enough for you to look at the phone and yell, “I won’t do that!”). At the beginning of that 2.0 s, the police officer begins braking suddenly at 5.0 m/s 2 . (a) What is the separation between the two cars when your attention finally returns? Suppose that you take another 0.40 s to realize your danger and begin braking. (b) If you too brake at 5.0 m/s 2 , what is your speed when you hit the police car?
GO You are arguing over a cell phone while trailing an unmarked police car by 25 m; both your car and the police car are traveling at 110 km/h. Your argument diverts your attention from the police car for 2.0 s (long enough for you to look at the phone and yell, “I won’t do that!”). At the beginning of that 2.0 s, the police officer begins braking suddenly at 5.0 m/s2. (a) What is the separation between the two cars when your attention finally returns? Suppose that you take another 0.40 s to realize your danger and begin braking. (b) If you too brake at 5.0 m/s2, what is your speed when you hit the police car?
You are arguing over a cellponone while trailing an unmarked police car by 27 m. Both your car and the police car are traveling at 105 km/h. Your argument diverts your attention from the police car for 1.5 s (long enough for you to look at the phone and yell, "I won't do that!"). At the beginning of that 1.5 s, the police officer begins emergency braking at 5 m/s2
Other known values:
The separation between the two cars when your attention finally returns is 21.37 m.
Suppose it takes you another 0.4 s to realize your danger and begin braking. If you also brake at 5 m/s2, your speed when you hit the police car is 70.81 km/h.
(a) How much time passes between your initial braking and the collision?
(b) How much distance do you cover during this time (i.e., while braking)?
A pedestrian is running at his maximum speed of 6.0 m/s to catch a bus stopped at a trafficlight. When he is 15 m from the bus, the light changes and the bus accelerates uniformly at 1.00m/s2. Does he make it to the bus? If so, how far does he have to run in order to catch it? If not,how close does he get?
You are arguing over a cell phone while trailing an unmarked police car by 27.0 m. Both your car and the police car are traveling at 100 km/h. Your argument diverts your attention from the police car for 2.30 s (long enough
for you to look at the phone and yell, "I won't do that!"). At the beginning of that 2.30 s, the police officer begins emergency braking at 5.00 m/s².
(a) What is the separation between the two cars when your attention finally returns?
m
(b) Suppose that you take another 0.400 s to realize your danger and begin braking. If you too brake at 5.00 m/s², what is your speed when you hit the police car?
km/h
Physics for Scientists and Engineers, Technology Update (No access codes included)
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