What is the force exerted by an oak tree on a jogging person after collision?

[StotleD]

If a healthy but somewhat direction impaired individual (mass = 81.9 kg) is jogging through the woods and runs straight into a large oak tree at 4.7 m/s. Rebound speed is measured at 4.2 m/s in the opposite direction. If the time of contact with the tree is 46 milliseconds, what is the magnitude of the force that the tree exerts on the jogger?

 

[Pyrrhus]

What have you done? I suggest applying the acceleration definition (a = \frac{\Delta v}{\Delta t}) directly into Newton's 2nd Law.

 

[KingNothing]

This is a simple application of an impulse. I = Force * time, and is also the change in momentum. Momentum is mass times velocity. Momentum before = 81.9 * 4.7 = 384.93. Momentum after=81.9*-4.2= -343.98. Impulse = 728.91 = force * time. Time=.46. 728.91=force * .46. Force is then equal to 1584.59 Newtons.