How long will it take an 850-kg car with a useful power output of 40.0 hp (1 hp equals 746 W) to reach a speed of 15.0 m/s, neglecting friction if the car also climbs a 3.00 m high hill in the pro?

The car will take 4 seconds.

Explanation:

First of all, we convert the power from hp to W:

The work done by the car is equal to the change in its mechanical energy. This means that:

Now, the change in mechanical energy in terms of the kinetic and potential energy is:

Since the initial height and the initial velocity are zero, we have:

Finally,

Plugging in the given values, we obtain:

In words, the car will take 4 seconds.