Hi everyone , I've searched the answer for this question for a while , but haven't reach an satisfying explanation yet . Generally , from the study of friction , any force that's smaller than the static friction between the wheel and the ground would cause the wheel rolling ( Otherwise the wheel would be sliding ) . But obviously when we push a car with a small force , it doesn't move . Somewhere on the internet , people say that's because of the internal friction between components inside the car . Then again , when we push a wheel alone , or a tyre , the more weight the tyre/wheel has , the greater force we have to apply to move it , obviously greater than the force we push a toy wheel to cause it rolling . So what's the exact explanation for this ? Does weight of the wheel have anything to do with the scale of the force applied to move it ? If yes , how's the calculation ? Thank you all for reading this and waiting for your reply .