Acar weighing 9800 n travels at 30 m/s. what braking force brings it to rest in 100m? in 10 m?

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

now braking force is given as

now for mass we know that the weight of car is

so mass of car is

now we have

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

now braking force is given as

mass of car is

now we have

this would be about 43%