question_answer

The driver of a truck travelling with a velocity v suddenly notices a brick wall in front of him at a distance d. It is better for him to apply brakes or to make a circular turn without applying brakes in order to just avoid crashing into the wall? Why?

Answer:

                In applying brakes, suppose \[{{\text{F}}_{\text{B}}}\] is the force required to stop the truck in distance (d) \[\therefore \]                  \[{{\text{F}}_{\text{B}}}\times \text{d }=~\frac{1}{2}\text{m}{{\upsilon }^{\text{2}}}\]  or \[{{\text{F}}_{\text{B}}}=\frac{m{{v}^{2}}}{2d}\] In taking a turn of radius d, the force required is \[{{\text{F}}_{\text{T}}}=\frac{m{{\upsilon }^{2}}}{d}=\text{2}{{\text{F}}_{\text{B}}}\]or \[{{\text{F}}_{\text{B}}}=\frac{1}{2}{{\text{F}}_{\text{T}}}\] Hence it is better to apply brakes.