A body with a mass of 20 kg, which had an initial speed of 18 km / h, under the influence of a friction force

A body with a mass of 20 kg, which had an initial speed of 18 km / h, under the influence of a friction force, passed a path of 25 m to a stop. What is the friction force.

Initial data: m (body weight) = 20 kg; V0 (initial speed that the body had) = 18 km / h (5 m / s); S (distance traveled by the body to stop) = 25 m.

1) Let’s define the acceleration with which the body moved: S = V0 ^ 2 / 2a, whence a = V0 ^ 2 / 2S = 5 ^ 2 / (2 * 25) = 0.5 m / s2.

2) Let’s calculate the magnitude of the friction force: Ffr = m * a = 20 * 0.5 = 10 N.

Answer: The friction force was 10 N.