Which two parts do the capillaries surround? A. small intestines and heart

B. heart and lungs

C. alveoli and small intestines​

How much force must a locomotive exert on a 12840-kg boxcar to make it accelerate forward at 0.490 m/s2?

Can anybody me with this? ? (picture included.)

Imagine that someone pushes one marble toward a motionless marble. would there still be action-reaction forces involved in the collision? how might the marbles’ motions be changed? ?