Just_One

For part A this is what I did and I got 20 for me and validated 25 for some of you. F=ma a=F/m Because this is not constant acceleration V=at^2. Do not divide by 2! Then P=mv which result in 25 for some of you and 20 for me.

Look at this however I am confused about the t^3. I know that is comes from integration but not sure of why the integration if the F(t)Bt^2 is supposed to describe you non linear force in function of a. answers yah_o_o c_om/ question/ index?qid=2013120703...

I got 6.99 for part B. F=.8 and m=3. Would you please verify. Part A for me is 33.33 Thanks.

Power should be the difference in KE when start moving and t final divided by time. Since KE and Power have the same unit and watts is a unit in function of time that is why you need to take the time interval of motion.

Why 90? assuming alpha=30 (let's just say) then the resulting angle will be 60 which does not make sense since the plane is already inclined at 30 degrees.

Ok I see it has not to be 45. If the slope is let say 55 that your angle will need to be larger than 45 and minor than 90. I would go (90+55)/2.