Find Net Force of 2.5x10^5N Training Helicopter

[xmflea]

The position of a 2.5x10^5N training helicopter under test is given by
r=(0.020m/s^3)t^3i + (2.2m/s)tj-(0.060m/s^2)t^2k , find the net force of the helicopter at t=5.0s

express F in the form Fx Fy and Fz

F=ma F=Fx+Fy+Fz


so far i plugged in t to each component to get 2.5m, 11m, and 1.5 m,
now i just need to know how to use the force that is given to find the x, y, and z components. need a little guidance.

 

[Doc Al]

The net force is not given, you have to figure it out. What does Newton's 2nd law say about net force? (That should give you a hint about what you need to do.)