A motor car of mass 800kg travelling at 20m/s is brought to rest by brake in 100m.calculate the average braking force required.in physics
20^2 = 2 (a) 100
Then F = ma
To calculate the average braking force required, we can use the equations of motion. The equation that relates distance, initial velocity, final velocity, and acceleration is:
v^2 = u^2 + 2as
where:
v = final velocity (0 m/s, since the car is brought to rest)
u = initial velocity (20 m/s)
a = acceleration (negative, as the car is decelerating)
s = distance (100 m)
Rearranging the equation, we get:
a = (v^2 - u^2)/(2s)
Plugging in the values, we get:
a = (0^2 - 20^2)/(2 * 100)
a = (-400)/200
a = -2 m/s^2
Now, we know the acceleration of the car. To calculate the force, we can use Newton's second law of motion:
F = ma
where:
F = force (unknown)
m = mass of the car (800 kg)
a = acceleration (-2 m/s^2)
Plugging in the values, we get:
F = 800 kg * (-2 m/s^2)
F = -1600 N
Since force has a negative sign, it indicates that the force is acting in the opposite direction of motion, which is the direction of braking. Therefore, the average braking force required is 1600 N in magnitude.