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

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

What gift did Della buy for Jim and why in "The Gift of the Magi" by O. Henry?

Della buys Jim a watch fob because his watch is his most prized possession. Della and Jim Young do not have much money. Despite this, Della really wants to buy Jim a good Christmas present. She is even willing to sell her hair to get him a nice gift. This is ironic because we learn Della and Jim both highly prize her hair. Now, there were two possessions of the James Dillingham Youngs in which... Della buys Jim a watch fob because his watch is his most prized possession. Della and Jim Young do not have much money. Despite this, Della really wants to buy Jim a good Christmas present. She is even willing to sell her hair to get him a nice gift. This is ironic because we learn Della and Jim both highly prize her hair. Now, there were two possessions of the James Dillingham Youngs in which they both took a mighty pride. One was Jim's gold watch that had been his father's and his grandfather's. The other was Della's hair.  Della is still willing to sell her hair so she can b...
Post a Comment
Read more

Explain and discuss how the definitions of freedom change for the nation, for the freedmen and for southern whites after the Civil War.

After the Civil War, the definition of freedom changed in the nation, as slavery was ended with the 13th Amendment to the Constitution in 1865. The practice of slavery was disallowed, but definition of the freedom that would take its place was a subject of controversy, ongoing debate, and even violence in the decades to come.  For freedmen, freedom often meant reconciling with their families, who were broken up by slavery; choosing which church to... After the Civil War, the definition of freedom changed in the nation, as slavery was ended with the 13th Amendment to the Constitution in 1865. The practice of slavery was disallowed, but definition of the freedom that would take its place was a subject of controversy, ongoing debate, and even violence in the decades to come.  For freedmen, freedom often meant reconciling with their families, who were broken up by slavery; choosing which church to belong to without being ordered to attend religious services (or not to attend) by their mast...
Post a Comment
Read more