The question states: How much force does an 81.0 kg astronaut exert on his chair while sitting at rest on the launch pad? the answer that I got was 794 N using... W=m*g and Fnet=w+fchair=0 But I cannot seem to get the right answer for this second question: How much force does the astronaut exert on his chair while accelerating straight up at 18.0 m/s^2? I know that Fnet= w+ Fchair and also Fnet= m*a so 81 kg * 18m/s^2= 794 + Fchair the answer I get for Fchair is 664 but its not the correct answer. what am I doing wrong??