Science
posted by Sarah on .
A bicycle and its rider have a combined mass of 90kg. The cyclist is accelerating at 0.5m/s^2. What minimum force is he exerting?
F=m•a
F=90kg•0.5m/s^2
F= 45N
However the answer on my answer key says 5×10^1

However the answer on my answer key says 5×10^1 N. I'm confused on how they got that

F = m a
F = 90*.5 = 45 N
so I agree with you
Maybe they are rounding to one significant figure because they say 0.5 and not 0.50 ? 
Oh. That makes sense. I misunderstood and thought 0.5 had 2 significant figures but it has 1. Thank you so much!