BR chapter 1, #17 in 52 q test: mass vs acceleration

[salsasunrise123]

I'm having trouble reconciling the fact that mass and acceleration are unrelated in kinematics problems yet inversely proportional when talking about force/f=ma. Problem 17 in 52 question test in chapter 1 of BR says they are unrelated when an object is pushed up air ramp, etc. can someone please explain this question and answer to me

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[brood910]

On the ramp = F = mgsin, assuming no frictional force.
Then, ma = mgsin, where m cancels out. Mass does not affect acceleration.
You should write out all the forces present and set them equal to ma to see what affects a.

p.s. I didnt look at the problems. This is just a basic fact regarding ramps.

 

[pjk77]

yep. even if frictional force, you'll get mgsintheta- ukmgcostheta= mg and m cancels all the way through.