# Forces that could cause an objects acceleration to increase when weights added

danielm93
I have propelled a wagon by a spring that gives out a constant force with various weights added and the wagons acceleration when the first weight is added increases from what it was with no weights. When the next weights are added the acceleration fall from what it rose to but I'm stumped.

Why does that acceleration increase if anything I thought it should decrease since F=ma and the force remains same while mass increases so in theory acceleration should decrease especially since the friction it experiences should increase and so should drag.

Daniel

## Answers and Replies

I have propelled a wagon by a spring that gives out a constant force with various weights added and the wagons acceleration when the first weight is added increases from what it was with no weights. When the next weights are added the acceleration fall from what it rose to but I'm stumped.

Why does that acceleration increase if anything I thought it should decrease since F=ma and the force remains same while mass increases so in theory acceleration should decrease especially since the friction it experiences should increase and so should drag.

Daniel

It's hard to say, because you are dealing with an imperfect real system. My guess is that the first weight causes the wheels to be in firmer contact with the ground, so that the energy from your drive train (spring) is more efficiently converted into forward motion. However, without knowing the details of your system, it is impossible to know if this is on the right track or not. Is there any "slipping" of the wheels when the wagon is empty, which goes away when you add the first weight?