CBSE Class 7 Science
Question 5 of 12
Measurement of Time and Motion — Question 5
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Question A runner completes 400 metres in 50 seconds. Another runner completes the same distance in 45 seconds. Who has a greater speed and by how much?
Runner 1:
Distance = 400 m,
Time = 50 s
SPeed = \(\frac{\text { Distance covered }}{\text { Time taken }}\) = \(\frac{400 \mathrm{~m}}{50 \mathrm{~s}}\) = 8 m/s
Runner 2:
Distance = 400 m,
Time = 50 s
SPeed = \(\frac{\text { Distance covered }}{\text { Time taken }}\) = \(\frac{400 \mathrm{~m}}{45 \mathrm{~s}}\) = 8.89 m/s
Difference = 8.89 – 8 = 0.89 m/s
Hence, speed of runner 2 is greater by approximately 0.89 m/s.