Martin won the 400m metre race in the school sports with a time of 1 minute. The distance was correct to the nearest tenth of a second. a)Work out the upper bound and the lower bound of Martin's speed in km/h. Give your answers to 5significant figures.
What I did:
Distance Time
UB 400.5 60.5
LB 399.5 59.5
But I don't know how to convert the m to Km and I don't know to do it for upper and lower bounds. Thank You and Help Is Appreciated.
To converted from metre to kilometre, divide by $1000$. To convert from seconds to hours, divide by $3600$.
Maximum velocity is when you travel the greatest distance in the least time and minimum velocity is when you travel the least distance in the greatest time.
PS How is the distance correct to the nearest tenth of a second? Please recheck your original question.
I understand that a $400$ m race is definitely $400$ m so the time is probably correct to the nearest $\frac 1{10}^{th}$ of a second.
The upper limit on the time is $60.05$s and the lower limit is $59.05$. Thus the maximum velocity in $m/s$ is $\frac {400}{59.05}$ and the minimum velocity is $\frac {400}{60.05}$. I hope you can carry on from here.