EK physics number 195

[2010premed]

Ig the object m slides down the plane in 3s, what is the ratio of the distance it travels in the 1st second compared to the distance it travels in the 3rd second?

Answer: 1:6

totally lost on this one...

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[CardiacArrest]

Probably because it's the wrong answer.
The answer is 1:5.

 

[2010premed]

sry yeah the answer is 1:5 I just wrote it wrong... I don't see how they got that though

 

[SoftwareKevin]

sry yeah the answer is 1:5 I just wrote it wrong... I don't see how they got that though

Let's say they're accelerating at x m/s^2.

Speed at end of 1st second: x
Speed at end of 2nd second: 2x
Speed at end of 3rd second: 3x

Average speed during first second: (x+0)/2 = x/2
Average speed during second second: (2x+x)/2 = 3x/2
Average speed during third second: (3x+2x)/2 = 5x/2

So we have average speed during third second and average speed during the first second. Their ratios are 1:5 and so the distances traveled during those periods will also be 1:5 since they're both over the same period of time.