Determine the power of a car that is moving evenly at a speed of 72 km / h with a traction force of 2000N

Let us take as the initial condition the definition of power (designation – N), as work performed in a certain time (unit of measurement – J / s or Watt), or – force required to move a body per unit of time (unit of measurement – Nm / s or the same Watt).

Let’s translate the vehicle speed given to us in the dimension of m / s (taking into account that 1 km is 1000 m, and 1 hour is 3600 seconds (in 1 hour – 60 minutes, each of which consists of 60 seconds: 60 * 60 = 3600)).

Then 72 km / h will mean 72000 m / 3600 s = 20 m / s.

The power of our car, therefore, will be equal, according to the formula (with uniform movement, that is, constant speed) – N = F * v.

We get:

N = 2000 N * 20 m / s = 400000 Nm / s or 40 kJ / s, or 40 kilowatts. This value is equal to the power of our car.