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Overcoming a Head Start Cars A and B are racing each other along the same straig

ID: 1394259 • Letter: O

Question

Overcoming a Head Start Cars A and B are racing each other along the same straight road in the following manner: Car A has a head start and is a distance DA beyond the starting line at t 0. The starting line is at a 0 Car A travels at a constant speed vA. Car B starts at the starting line but has a better engine than Car A, and thus Car B travels at a constant speed vB which is greater than vA Part A How long after Car B started the race will Car B catch up with Car A? Express the time in terms of given quantities. AE catch Submit Hints My Answers Give Up Review Part Incorrect; Try Again; 6 attempts remaining Part B How far from Car B's starting line will the cars be when Car B passes Car A? Express your answer in terms of known quantities. (You may use catch as well.) AE

Explanation / Answer

Speed of A = vA

Speed of B = vB

Extra distance to be travelled by B compared to A = DA

Time taken to catch car A by car B = extra distance / relative speed of B wrt A = DA / ( vB - vA )

Answer : tcatch =  DA / ( vB - vA )

dpass = Speed of B x time taken to pass

dpass = vBtcatch  

Answer :  dpass   = vB tcatch