College Physics, 10e (Young) Chapter 2 Motion Along a Straight Line 1. A car acc
ID: 1782644 • Letter: C
Question
College Physics, 10e (Young) Chapter 2 Motion Along a Straight Line 1. A car accelerates from 5.0 m's to 21 m/s at a rate of 3.0 m/s2, How far does it travel while accelerating? A) 69 m B) 207 m C)41 m D) 117 m A racquetball strikes a wall with a speed of 30 m/s and rebounds with a speed of 26 m/s. The collision takes 20 ms. What is the average acceleration of the ball during the collision? 2. A) zero B) 200 m/s2 C) 2800 m/s2 D) 1500 m/s2 E) 1300 m/s2 3. Which of the following situations is impossible? A) An object has velocity directed east and acceleration directed west. B) An object has velocity directed east and acceleration directed east. C) An object has zero velocity but non-zero acceleration. D) An object has constant non-zero acceleration and changing velocity E) An object has constant non-zero velocity and changing acceleration. 4. A racing car accelerates uniformly from rest along a straight track. This track has markers spaced at equal distances along it from the start, as shown in Figure 2.2. The car reaches a speed of 140 km/h as it passes marker 2. Figure 2.2 speed = 0 peed 140 lanh Marker 1 Marker 2 Start Whereabouts on the track was the car when it was travelling at half this speed, i.e. at 70 km/h? A) Before marker 1 B) At marker 1 C) Between marker 1 and marker 2 Copyright 0 2016 Pearson Education, Inc.Explanation / Answer
1) V^2= U^2 +2as
a = (441-25)/6 = 69 m/sec^2 (ans)
2) a avg = [26-(-30)]/(20) *1000 = 2800 m/sec^2 (ans)
3) An object has zero velocity but non zero accleration.
4) V^2 =U^2 + 2as
140^2 = 2*a*(2s)
a = 4900/s
When V= 70
s = V^2/2a = 4900/(2*4900/s) = s/2
So it was before marker 1 (ans)