EK Physics 1001 Page 6 number 51

[2010premed]

A particle starts from rest and travels in a straight line for 4 s. If the particle is accelerating at a constant rate, which of the following could be the total distance traveled by the particle at the end of each consecutive second?

answer: 5m, 20m, 45m, 80m

I get that it shouldn't be constant, but I don't get the exact way they get those numbers

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[PiBond]

A particle starts from rest and travels in a straight line for 4 s. If the particle is accelerating at a constant rate, which of the following could be the total distance traveled by the particle at the end of each consecutive second?

answer: 5m, 20m, 45m, 80m

I get that it shouldn't be constant, but I don't get the exact way they get those numbers

it looks like they used y=1/2at^2 and thus the acceleration would be 10m/s^2

 

[surag]

it looks like they used y=1/2at^2 and thus the acceleration would be 10m/s^2

That's not the point. They purposefully left out the acceleration to force u to understand the relationship bw v an a. I'm assuming there were other choices present w similar distances albiet at different intervals bw distances and were the wrong answers.

The point is u need to look for a choice with increasing CONSTANT velocity. If u look at a v vs t graph ull notice that it's an increasing line at constant acceleration. That means that each second the velocity is increasing. But at a CONSTANT rate. Thus the distance should increase by a constant plus constant x rate. In this case the distance increases by plus 10 over thr previous difference.