Question

A cyclist is capable of generating an average power of 3.0 kW during a 4 km speed trial. He is in aerodynamic suit and position on the cycle reduce resistive forces to 180 N. What is the approximate time achieved in the speed trial?​

Answer 1

Answer:

240 sec = 4 min

Explanation:

3t.10³ = 180 (4x10³)

t = 180x4/3 = 240 sec = 4 min

Answer 2

The approximate time achieved in the speed trial is 240 sec or 4 minutes.

Explanation:

Given:

• Average power = 3 kW= 3000 W
• Distance 's'= 4 km = 4000 m
• Resistive force 'f'= 180 N

The work done by cyclist to generate the power is given by

$= > w = p \times t$

$= > w = 3000 \times t$

The work done by cyclist to reduce resistive forces is given by

$= > w = f \times s$

$= > w = 180 \times 4000$

Now compare both work done by the same body

$= > 3000 \times t = 180 \times 4000$

$= > t = \frac{180 \times 4}{3}$

$= > t = 60 \times 4 \: sec$

$= > t = 240 \: sec \: or \: 4 \: min$

The approximate time achieved in the speed trial is 240 sec or 4 minutes.