a 72kg runner is jogging at a rate of 6.0m/s and then begins to sprint, reaching a full speed of 15.0m/s after 3.0s. what is the net force acting on the runner?
To calculate the net force acting on the runner, we need to use Newton's second law of motion, F = ma, where F is the net force, m is the mass, and a is the acceleration.
First, the initial velocity of the runner is 6.0 m/s. After 3.0 seconds, the final velocity increases to 15.0 m/s. We can calculate the acceleration using the formula a = (vf - vi) / t, where vf is the final velocity, vi is the initial velocity, and t is the time interval.
Plugging in the values, we have a = (15.0 m/s - 6.0 m/s) / 3.0 s = 9.0 m/s^2.
Next, we can calculate the net force using F = ma.
Plugging in the values, we have F = (72 kg) * (9.0 m/s^2) = 648 N.
Therefore, the net force acting on the runner is 648 Newtons.