题目

一道SAT2物理题,
Q:When a woman pushes on her grocery cart,the woman moves because of ()
the answer is the force that the ground exerts on the woman.
In light of the net force,the woman horizontally gets the opposite reaction from the cart and the friction of the ground.
I really wonder which one is the main factor.
PS:In the question,it does't tell me anything about frictional coefficient,thus I think there is friction on the ground by default.
I owe you!

提问时间：2020-10-31

答案

不知道你能不能看懂中文,看不懂我再翻译.女子移动是因为在她推cart时,cart也同时给她了一个相互作用力,与她的推力相反.cart没有动是因为那个推力小于它的最大静摩擦力,而女人动了是因为那个相互作用力大于她与地面的最大静摩擦力,从而使女人受的合力相反导致移动.也就是你提到第二种的解释