To determine the magnitude of the braking force experienced by John, we can use Newton's second law of motion, which states that the force acting on an object is equal to the mass of the object multiplied by its acceleration. In this case, the deceleration due to braking will be considered as a negative acceleration.
Given: Mass of John (m) = 63 kg Initial velocity (u) = 8.5 m/s Final velocity (v) = 0 m/s Time taken (t) = 3.0 s
Acceleration (a) can be calculated using the formula:
a = (v - u) / t
Substituting the given values:
a = (0 - 8.5) m/s / 3.0 s a = -8.5 m/s / 3.0 s a = -2.83 m/s²
The negative sign indicates that the acceleration is in the opposite direction to the initial motion.
Now, we can calculate the magnitude of the braking force using Newton's second law:
F = m * a
Substituting the values:
F = 63 kg * -2.83 m/s² F = -178.29 N
The magnitude of the braking force experienced by John is approximately 178.29 N.