Need help

[strugglin-physics]

A particular race car can cover a quarter-mile track (402 m) in 6.27 seconds, starting from a standstill. Assuming the acceleration is constant, how many "g's" does the driver experience?

This has to be a really easy problem as I am given the m and the sec but I can not figure out what formula to use for this problem...

Please help.

[buddingscientist]

x = x + vt + 1/2at^2
402m = 0 + 0 + 1/2(a)(6.27^2)
804m = 39.3129a
a = 804/39.3129
a = 20.45m/s/s

since one 'g' = 9.8
the driver experiences a little bit over 2 g's?

[strugglin-physics]

OH that makes sense. I was trying to use the formula F=ma to solve the problem. Oops. Thank you much for your assistance.

[strugglin-physics]

Maybe you could help me with this problem also?
The position of a mass m = 24 kg is given (in m) by x(t) = 7sin(5t). Calculate the magnitude of the maximum force acting on the mass.

I know that acceleration is the double prime of the formula but I don't know how to find the maximum force.