Question

Calculate the power required to accelerate a 1150 kg car from rest to a final velocity of 30 m/s up a 100 m long uphill road with a slope of 30 degrees from horizontal over a time of 12 seconds. Disregard friction, air drag, and rolling resistance.

Answer 1

Answer:

power required is 90.131 kW

Explanation:

Given data

mass of car (m) = 1150 kg

starting velocity (v1) = 0 m/s

final velocity (v2) = 30 m/s

slope angle = 30 degrees

slope distance = 100 m

to find out

power required

solution

we know the power =  work / time

here time is given we have calculate the work

work is for car climb 100 m distance is total sum of potential energy + kinetic energy

and we know car climb 100m at 30 degree slope so vertical distance (h) will be h = 100 sin (30) = 50 m

so now potential energy = mass × gravity × height

potential energy = 1150 × 9.81 × 50 = 564075 J

kinetic energy = 1/2 ×mass × velocity²

kinetic energy = 1/2 ×1150 × ( v2 - v1 )²

kinetic energy = 1/2 ×1150 × ( 30 - 0 )² = 517500 J

now put all value in power formula

power = work / time

power = potential energy + kinetic energy / 12

power = 564075  +  517500  / 12 = 90131.25 W

power = 90.131 kW