Question

When we drive our car at 90 feet per second​ [ft/s], we measure an aerodynamic force​ (called drag) of 59 ​pounds-force ​[lbf​] that opposes the motion of the car. How much horsepower​ [hp] is required to overcome this​ drag?

Answer 1

P = 9.65 hp

Step-by-step explanation:

Given that,

Speed of a car, v = 90 ft/s

Force that opposes the motion of the car, F = 59 pounds-force

90 ft/s = 27.432 m/s

1 pound-force = 4.448 N

59 pounds-force = 262.445 N

Power required is given by :

`P=F* v\\\\P=262.445\ N* 27.432\ m/s\\\\P=7199.391\ W`

Since, 1 hp = 745.7

7199.391 W = 9.65 hp

So, 9.65 hp of power is required to overcome the drag.