How Is the Mass of a Kart Represented in a Force vs. Acceleration Graph?

[blee2x2]

I have a graph of force vs. acceleration of a kart on a a ramp that i manually pushed back and forth with my hand.

The mass of the the kart is .6485kg and when i did the linear fit it said that slope of the graph was .5586N/m/s^2 and the intercept .2097 N

My question is would i see the mass of the kart represented in both the slope and the intercept or just the slope?

I know the F=ma and in a perfect setting with not other forces the intercept should be 0.

 

[blee2x2]

my linear equation would be Force = .5586N/m/s^2(a) + .2097N

 

[haruspex]

You should offer your own opinion first.
How do you interpret the nonzero intercept?