Answer:
0.0986 h or 5 minutes 55 seconds.
Explanation:
Speed: This can be defined as the rate of change of distance of a body. The S.I unit of speed is m/s. Speed is a scalar quantity, because it can only be represented by magnitude alone.
Mathematically,
Speed = distance/time.
S = d/t ........................... Equation 1
making t the subject of the equation
t = d/S ......................... Equation 2
Form the question,
Time taken for the faster runner to reach the finish line
t₁ = d/S₁................... Equation 3
Where t₁ = time taken for the faster runner to reach the finish line, d = distance, S₁ = speed of the faster runner.
Given: d = 5.0 km, S₁ = 14.7 km/h.
Substituting into equation 3
t₁ = 5/14.7
t₁ = 0.340 h
Also,
t₂ = d/S₂................... Equation 4
Where t₂ = time taken for the slower runner to reached the finished line, d = distance, S₂ = speed of the slower runner.
Given: d = 5 km, S₂ = 11.4 km/h.
Substitute into equation 4,
t₂ = 5/11.4
t₂ = 0.4386 h.
The time the faster runner have to wait at the finish line to see the slower runner cross = t₂ - t₁ = 0.4386-0.340
The time the faster runner have to wait at the finish line to see the slower runner cross = 0.0986 h = 5 mins 55 s.
