Skip to main content

Figure A and B show the speed- time graphs of two cars (a) and (b) respectively. Using these graphs answer the following questions: (i) What is...

 Acceleration is the rate of change of velocity. In other words,


acceleration = (final velocity - initial velocity) / (final time - initial time)


Thus, for car B, 


in first two hours: v = 40 km/h, u = 0 km/h and t = 2 h


thus, a = (40 - 0)/2 = 20 km/h^2


in next two hours: v = u = 40 km/h, thus, acceleration = 0 km/h^2


and in last 2 hours: v...

 Acceleration is the rate of change of velocity. In other words,


acceleration = (final velocity - initial velocity) / (final time - initial time)


Thus, for car B, 


in first two hours: v = 40 km/h, u = 0 km/h and t = 2 h


thus, a = (40 - 0)/2 = 20 km/h^2


in next two hours: v = u = 40 km/h, thus, acceleration = 0 km/h^2


and in last 2 hours: v = 0, u = 40 km/h and t = 2 h


thus, acceleration = (0 - 40)/2 = -20 km/h^2.


Similarly, for car A,


in first two hours: acceleration = (30 - 0)/2 = 15 km/h^2


for next 2 hours, acceleration = (60 - 30)/2 = 15 km/h^2


and in the last 2 hours, acceleration = (0 - 30)/2 = -15 km/h^2


(ii) Total distance traveled by Car (B): 


Average velocity in first 2 hours = (0 + 40)/2 = 20 km/h


average velocity for next 4 hours = 40 km/h


and average velocity for last 2 hours = (40 + 0)/2 = 20 km/h


thus distance traveled = 20 km/h x 2 h + 40 km/h x 4 h + 20 km/h x 2 h


= 40 km + 160 km + 40 km = 240 km.


Similarly for car (A):


distance traveled = average speed x time = (0 + 30)/2  km/h x  2 h + (30 + 60)/2 km/h x 2 h + (60 +30)/2 km/h x 2 h + (30 + 0)/2 km/h x 2 h = 240 km


The distance traveled by both cars is same.


The distance traveled can also be determined as the area under the curve. For example, for car A: distance = area under the curve = area of triangle with base 8 hr and height 60 km/h = 1/2 x 8 h x 60 km/h = 240 km.


(iii) Average speed = distance traveled/time taken = 240 km/8 h = 30 km/h


Since both the cars traveled the same distance in the same time, the average speed is the same and is equal to 30 km/h.


Hope this helps. 

Popular posts from this blog

In chapter one of The Great Gatsby, what advice does Nick's father give him? How does this make him a good person to tell this story?

Nick says that his father advised him that, before "criticizing anyone," he "remember that all the people in this world haven't had the same advantages" as Nick.  As a result, Nick claims that he is "inclined to reserve all judgments," presenting himself to the reader as a fair and dispassionate arbiter of character, and thus, a reliable narrator.   The problem is that Nick immediately reveals himself as anything but reliable, as he then launches... Nick says that his father advised him that, before "criticizing anyone," he "remember that all the people in this world haven't had the same advantages" as Nick.  As a result, Nick claims that he is "inclined to reserve all judgments," presenting himself to the reader as a fair and dispassionate arbiter of character, and thus, a reliable narrator.   The problem is that Nick immediately reveals himself as anything but reliable, as he then launches into a discussion of how pe...
Post a Comment
Read more

How did the United States become an imperial power?

"Imperial power" is a bit of a vague label. It tends to mean several things at once, so let's unpack it. In the sense of "this country was built on conquest by force," the "imperial power" part of America actually predates the United States proper. The territories that would become the United States were imperial colonies, established by the great European empires of the 17th and 18th centuries. Much of the US Constitution and American governance generally goes back to England, history's largest and most successful imperial power, but vital aspects of American culture come from other imperial powers, such as France and Spain. Much of American culture comes from sources other than the old empires, but they were key influences on what the United States became. In the sense of "this country treats conquest by force as a fundamental component of its culture, economy and politics," the United States has always been an imperial power. Even earl...
Post a Comment
Read more

How and why does James Gatz become Jay Gatsby? Describe the young Gatsby/Gatz.

James Gatz, a poor Midwestern boy of probable Jewish lineage, becomes Jay Gatsby, a presumed WASP and wealthy socialite, when he moves to New York City and acquires his fortune. It is wealth that has allowed Gatz to transform himself into Gatsby. However, those who know his background (e.g., Daisy and Tom Buchanan) never allow him to forget that he is nouveau riche -- that is, an upstart who has just recently made his fortune,... James Gatz, a poor Midwestern boy of probable Jewish lineage, becomes Jay Gatsby, a presumed WASP and wealthy socialite, when he moves to New York City and acquires his fortune. It is wealth that has allowed Gatz to transform himself into Gatsby. However, those who know his background (e.g., Daisy and Tom Buchanan) never allow him to forget that he is nouveau riche -- that is, an upstart who has just recently made his fortune, whereas they arose from well-to-do families. Gatz became Gatsby through determination and discipline. At the end of the novel, the narr...
Post a Comment
Read more