To determine the mass, divide by 9.8. Mass = 1000 kg
To determine the acceleration, use the following equation.
vf^2 = vi^2 + 2 * a * d, vf = 0, vi = 30
Let’s use this equation.
0 = 30^2 + 2 * a * 100
a = -900 ÷ 200 = -4.5 m/s^2
F = 1000 * -4.5 = -4,500 N
The force is negative, because it is causing the car’s velocity to decrease.
0 = 30^2 + 2 * a * 10
a = -900 ÷ 20 = -45 m/s^2
F = 1000 * -45 = -45,000 N
The magnitude of the force is inversely proportional to the distance the car moves while the brakes are being applied. I hope this helps you to understand how to solve this type of problem.
Answers & Comments
F = m * a
To determine the mass, divide by 9.8. Mass = 1000 kg
To determine the acceleration, use the following equation.
vf^2 = vi^2 + 2 * a * d, vf = 0, vi = 30
Let’s use this equation.
0 = 30^2 + 2 * a * 100
a = -900 ÷ 200 = -4.5 m/s^2
F = 1000 * -4.5 = -4,500 N
The force is negative, because it is causing the car’s velocity to decrease.
0 = 30^2 + 2 * a * 10
a = -900 ÷ 20 = -45 m/s^2
F = 1000 * -45 = -45,000 N
The magnitude of the force is inversely proportional to the distance the car moves while the brakes are being applied. I hope this helps you to understand how to solve this type of problem.
mass m = (9800 N) / (9.8 m/s²) = 1000 Kg
initial velocity u = 30 m/s
final velocity v = 0
a) time t = 100 m = 6000 s
acc = (v-u)/t = (0 - 30)/6000 = - 1/200 m/s²
Force = mass x acc = 1000 x (-1/200) = - 5 N
b) time t = 10 m = 600 s
acc = (v-u)/t = (0 - 30)/600 = - 1/20 m/s²
Force = mass x acc = 1000 x (-1/20) = - 50 N