Ch2-H2-solutions - chauhan (mmc2762) Ch2-H2 turner (56910)...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: chauhan (mmc2762) Ch2-H2 turner (56910) 1 This print-out should have 18 questions. Multiple-choice questions may continue on the next column or page find all choices before answering. 001 (part 1 of 2) 10.0 points Youre driving on a straight road (in the + x direction) at a constant speed of 25 m / s. In 8 s, you speed up to 42 m / s to pass a truck. Assuming that your car speeds up at a con- stant rate (constant force by the road on the tires), what is your average x component of velocity v avg ,x during this maneuver? Correct answer: 33 . 5 m / s. Explanation: Since the car speeds up at a constant rate, we just need to consider the endpoints, when the car was traveling v i,x = 25 m / s and v f,x = 42 m / s . We calculate the average x component of ve- locity as follows: v avg ,x = v i,x + v f,x 2 = 25 m / s + 42 m / s 2 = 33 . 5 m / s . 002 (part 2 of 2) 10.0 points How far do you go during this maneuver? Correct answer: 268 m. Explanation: Again, the fact that the acceleration is con- stant simplifies things. We can just treat this situation as though we were actually moving at the average speed for the 8 s interval: x = = v avg ,x t = (33 . 5 m / s)(8 s) = 268 m . 003 (part 1 of 3) 0.0 points On a straight road (taken to be in the + x direction) you drive for an hour at v 1 ,x = 40 km / h , then quickly speed up to v 2 ,x = 120 km / h and drive for an additional two hours. How far do you go ( x )? Correct answer: 280 km. Explanation: To find the total distance traveled, we have to consider the two speeds separately: x = v 1 ,x t 1 + v 2 ,x t 2 = (40 km / h)(1 h) + (120 km / h)(2 h) = 280 km . 004 (part 2 of 3) 0.0 points What is your average x component of velocity ( v avg ,x )? Correct answer: 93 . 3333 km / h. Explanation: We cant simply take the arithmetic mean in this case, because the car did not accelerate at a constant rate between the initial and final speeds. Instead, we have to take a weighted average, considering the two speeds and how long the car spent at each speed: v avg ,x = v 1 ,x t 1 + v 2 ,x t 2 t 1 + t 2 = (40 km / h)(1 h) + (120 km / h)(2 h) 2 h + 1 h = 93 . 3333 km / h . 005 (part 3 of 3) 0.0 points chauhan (mmc2762) Ch2-H2 turner (56910) 2 Is v avg ,x equal to the arithmetic average of your initial and final values of v x ?...
View Full Document

Page1 / 8

Ch2-H2-solutions - chauhan (mmc2762) Ch2-H2 turner (56910)...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online