a motor car of mass 800kg travelling at 20m/s is brought to rest by breakes in 100m.calculate the average breaking force required.in physics

using V2=U2+2aS

a=V2_U2/2S=20*20/2*100=400/200=2m/s2

F= ma
F=800*2=1600N

Is the answer correct

Good

To calculate the average braking force, we can use the equation:

Force = (final velocity^2 - initial velocity^2) / (2 x distance)

Given:
Mass (m) = 800 kg
Initial velocity (u) = 20 m/s
Final velocity (v) = 0 m/s (as the car is brought to rest)
Distance (s) = 100 m

Plugging these values into the equation, we get:

Force = (0^2 - 20^2) / (2 x 100)

First, let's calculate the numerator:

0^2 - 20^2 = -400

Now, let's calculate the denominator:

2 x 100 = 200

Now let's divide the numerator by the denominator:

Force = -400 / 200 = -2 N

The negative sign indicates that the force is acting in the opposite direction to the motion of the car, which is the direction of braking. Since the force cannot be negative, we take the absolute value, resulting in:

Average braking force = 2 N

Use kinematics equation:

v1²-v0²=2aS

v1=final velocity (0 m/s)
v0=initial velocity (20 m/s)
S=distance travelled (100 m)
solve for
a=acceleration (negative because it's a deceleration)

Use Newton's second law
F=ma
m=mass
F=average (uniform) force over the deceleration.