Final answer:
The work done by the tackler on the runner is calculated using the work-energy principle and equates to a negative change in the runner's kinetic energy, amounting to -842.5 joules.
Step-by-step explanation:
To determine the work done by the tackler on the runner, we can use the work-energy principle which states that work done is equal to the change in kinetic energy. Since the rugby player comes to a stop after the tackle, the final kinetic energy is zero and the work done is equal to the negative of the initial kinetic energy.
The initial kinetic energy (KE) can be calculated using the formula KE = ½⋅mv², where m is the mass of the runner and v is the velocity of the runner before the tackle.
Plugging in the values, we have KE = ½⋅(62.5 kg)⋅(5.2 m/s)² = ½⋅5²6.25 kg⋅(5.2 m/s)² = 842.5 J
Therefore, the work done on the runner by the tackler is -842.5 joules (negative because it's work done against the runner's motion).