Question

What is the minimum work needed to push a 950-kg car 710 m up along a 9.0° incline? ignore friction?

Answer 1

1.0344645 MJ The minimum energy need is the potential energy of the car at the top of the ramp and is given by mass*gravity*height mass is known, gravity is assumed to be 9.81m/s^2 as it is on earth, and height must be calculated using trigonometry. height=sin(9 degrees)*710m=111meters so potential energy = 950kg*111m*9.81m/s^2=1.0344645 MJ Using the law of the conservation of energy we can assume that the energy expended to push the car up the incline was at least the potential energy gained by moving 111m against the pull of gravity.

Answer 2

Answer:

Work done, $W=1.03\times 10^6\ J$

Explanation:

It is given that,

Mass of the car, m = 950 kg

Distance up to the incline, d = 710 m

Angle of inclination of the car is 9 degrees.

When the car is push in the inclined path, the vertical component of the force will act on it such that the work done is given by :

$W=mg\ sin\theta\times d$

$W=950\times 9.8\times \ sin(9) \times 710$  

$W=1.03\times 10^6\ J$

So, the minimum work needed to push a car is $1.03\times 10^6\ J$. Hence, this is the required solution.