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. 

Comments

Post a Comment

Popular posts from this blog

Can you analyze the poem "Absolution" by Siegfried Sassoon?

Sure! Siegfried Sassoon fought in World War I and was wounded in battle; he spent much of his life speaking out against war, and these pacifist feelings are easy to see in his poems. This one, "Absolution," was published in 1917, the same year that Sassoon was hospitalized for what we know today as post-traumatic stress disorder. "Absolution" is a short poem that contains three stanzas of four lines each. The word "absolution" means "forgiveness," and... Sure! Siegfried Sassoon fought in World War I and was wounded in battle; he spent much of his life speaking out against war, and these pacifist feelings are easy to see in his poems. This one, "Absolution," was published in 1917, the same year that Sassoon was hospitalized for what we know today as post-traumatic stress disorder. "Absolution" is a short poem that contains three stanzas of four lines each. The word "absolution" means "forgiveness," and the v...
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

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