Question

A car travels in a straight line at speed v along a horizontal road.the car moves against a resistive force f given by the equation F=400+kv2 where f is in Newton's,v in ms-1 and k is constant.At speed v=15ms-1,the resistive force f is 1100N calculate (i) the power necessary to maintain the speed of 15ms-1,(I)the total resistive force at a speed of 30ms-1, (I) the power required to maintain the speed of 30ms-1

Answer 1

Answer:

(i) Power = Force * Velocity = 1100 * 15 = 16500 W = 16.5 kW

(ii)  Find the value of k first: F = 400 + k(15^2)

                                             k = 28/9

   F = 400 +(28/9)(30^2) = 3200 N

(iii) Power = Force * Velocity = 3200 * 30 = 96000 W

Explanation: