As per kinematics equation we know that
final speed of the car = 0 m/s
initial speed is given as 30 m/s
distance moved = 100 m
now we have
[tex]v_f^2 - v_i^2 = 2 a d[/tex]
[tex]0 - 30^2 = 2(a)(100)[/tex]
[tex]a = - 4.5 m/s^2[/tex]
now braking force is given as
[tex]F = ma[/tex]
now for mass we know that the weight of car is
[tex]W = mg = 9800 N[/tex]
so mass of car is
[tex]m = 1000 kg[/tex]
now we have
[tex]F = 1000(4.5) = 4500 N[/tex]
Part b)
Again we have
final speed of the car = 0 m/s
initial speed is given as 30 m/s
distance moved = 10 m
now we have
[tex]v_f^2 - v_i^2 = 2 a d[/tex]
[tex]0 - 30^2 = 2(a)(10)[/tex]
[tex]a = - 45 m/s^2[/tex]
now braking force is given as
[tex]F = ma[/tex]
mass of car is
[tex]m = 1000 kg[/tex]
now we have
[tex]F = 1000(45) = 45000 N[/tex]
