A cyclist’s average power output when climbing a mountain is 280 W - Leaving Cert Physics - Question (a) - 2016

To determine the energy used by the cyclist, we can use the formula:

$E = P imes t$

Where:

• $E$ is the energy in joules,
• $P$ is the power in watts,
• $t$ is the time in seconds.

Given:

• Power, $P = 280 \, ext{W}$
• Time, $t = 18 \, ext{minutes} = 18 imes 60 \, ext{seconds} = 1080 \, ext{s}$

Now substitute the values into the equation:

$E = 280 \, ext{W} imes 1080 \, ext{s}$

Calculating the above gives:

$E = 302400 \, ext{J}$

Therefore, the cyclist uses 302400 J of energy.