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A racing car reaches a speed of 42 m/s. It then begins a uniform negative acceleration, using its parachute and braking system, and comes to rest 5.5 s later. Find the distance that the car travels during braking

Respuesta :

As per the question the initial speed of the car [ u] is 42 m/s.

The car applied its brake and comes to rest after 5.5 second.

The final velocity [v] of the car will be zero.

From the equation of kinematics we know that

                                         [tex]v=u+at[/tex] [ here a stands for acceleration]

                                         [tex]0=42 +5.5a[/tex]

                                         [tex]a =\frac{-42}{5.5} m/s^2[/tex]

                                          [tex]a= -7.64 m/s^2[/tex]

Here a is taken negative as it the car is decelerating uniformly.

We are asked to calculate the stopping distance .

From equation of kinematics we know that

                                              [tex]S=ut+\frac{1}{2} at^2[/tex]  [here S is the distance]

                                                      [tex]= 42*5.5 +\frac{1}{2} [-7.64] [5.5]^2 m[/tex]

                                                       [tex]=115.445 m[/tex]      [ans]