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

To find the energy used, we can use the formula:

$E = Pt$

where:

• $E$ is the energy in joules (J)
• $P$ is the power in watts (W)
• $t$ is the time in seconds (s)

First, convert the time from minutes to seconds:

$t = 18 ext{ minutes} \times 60 = 1080 ext{ seconds}$

Now, plug the values into the energy formula:

$E = 280 ext{ W} \times 1080 ext{ s} = 302400 ext{ J}$

Thus, the cyclist uses 302400 J of energy.