Physics question about deceleration.

Question

When landing after a spectacular somersault, a 50.0 kg gymnast decelerates by pushing straight down on the mat. Calculate the force (in N) she must exert if her deceleration is 6.00 times the acceleration of gravity. I get 2940, but the practice says that the answer is 34430. How is it getting that?

Answer 1

Newton's 2^nd law:

F_n - mg = ma, where a = 6g (upwards to decelerate her fall on the mat).

You have to solve that for the normal force F_n.

I think you forgot the mg in the equation, so you are getting a smaller answer.

Try this out and let me know if you have any additional questions. I hope this helps.