## The “horse” power of Santa’s Reindeer

We’ve previously looked at how fast Santa’s sleigh goes, and how heavy his sleigh would be when loaded up with all the presents.

But how much power is needed to get that sleigh moving? Many of us would be familiar with the term “horsepower” which was first used to compare the power of steam engines to the power of horses. Santa’s reindeer are a fair bit smaller than the average horse, however we’ll give them the benefit of the doubt and assign each reindeer 1 horsepower.

We’ve previously discussed the possible speeds that Santa might have to travel, and we can use that estimation to calculate the amount of “work” to be done to get the sleigh up to that speed. If we use 83,000m/s as the target speed, and the sleigh is stationary to begin with then we need about 14 trillion Megajoules of work to get the sleigh to speed.

If we give the reindeer 10 seconds to get the sleigh going (Santa is on a tight schedule) then that is 1.4 Trillion MegaWatts. 1 horsepower = 1 reindeer power = 746 Watts. Santa therefore needs 1.8 thousand trillion reindeer.

That is a lot of reindeer!