To calculate the retardation (deceleration) produced in the car, you can use the following equation:
v^2 = u^2 + 2as
where:
- v is the final velocity (0 m/s since the car comes to rest),
- u is the initial velocity (18 km/h converted to m/s),
- a is the retardation (unknown),
- s is the distance traveled (5 m).
First, we need to convert the initial velocity from km/h to m/s. Since 1 km/h is equal to 0.2778 m/s, we can calculate the initial velocity as follows:
u = 18 km/h * 0.2778 m/s per km/h
u ≈ 5 m/s
Now, we can substitute the known values into the equation and solve for the retardation (a):
0^2 = 5^2 + 2 * a * 5
0 = 25 + 10a
10a = -25
a = -25 / 10
a = -2.5 m/s^2
Therefore, the retardation produced in the car is approximately -2.5 m/s^2 (negative sign indicates deceleration).