The sports car has a mass of 1.5 Mg Mg and a center of mass at G. Determine the shortest time it takes for it to reach a speed of 80 km/h km/h, starting from rest, if the engine only drives the rear wheels, whereas the front wheels are free rolling. The coefficient of friction between the wheels and road is μ=0.2μ=0.2. Neglect the mass of the wheels for the calculation.

Explanation:

The figure of the problem is included below as attachment. The equations of equilibrium are presented below:

The system of equations are:

The solution of the system is:

, and

The shortest time to reach a speed of 80 km/h is:

the box does not move because you need to use a force greater than 300 n. you are only using 50 n. it needs to at least be 301 n for the box to move because then it is an unbalanced force and it will move the way that the greater force is pushing it. if you use only 300 n it will be a balanced force and will not move because the force you are exerting on the   box is the same as its force.

hope this !

im sorry if i went too in depth, i am going to include a link to a video on khan academy that will explain this.   hope that you like the video and that it explains more in detail to you.

that is the link.