What constant force does the floor exert

[HJ^2]

Right. The only unknown there is Fn. Solve.

Fn = (m*a) - Fg

With variables is;

Fn = (74.4 * 6.8411) - 9.8 = 499.177 ?

 

[haruspex]

Fn = (m*a) - Fg

With variables is;

Fn = (74.4 * 6.8411) - 9.8 = 499.177 ?

Fg is not 9.8 For one thing, it will be negative (since you have chosen up as positive).

 

[HJ^2]

Fg is not 9.8 For one thing, it will be negative (since you have chosen up as positive).

Fgrav = -9.8*74.4?
If that's right, then;
Fn = (74.4*6.8411) - (-729.12) = 1238.10

 

[haruspex]

Fgrav = -9.8*74.4?
If that's right, then;
Fn = (74.4*6.8411) - (-729.12) = 1238.10

Right (but shared across two feet).
So, do you see where your prof went wrong?

 

[HJ^2]

Right (but shared across two feet).
So, do you see where your prof went wrong?

Absolutely. I'll have to bring it up to her as I'm sure my class mates had similar concerns.

 

[haruspex]

Absolutely. I'll have to bring it up to her as I'm sure my class mates had similar concerns.

Good.
On a side note, if you calculate how far the athlete's mass centre must travel after touch down and before coming to rest, it's about 3m!

 

[HJ^2]

Good.
On a side note, if you calculate how far the athlete's mass centre must travel after touch down and before coming to rest, it's about 3m!

Oh thanks! And thank you so much for your help + everyone else in this thread :)