Is this a true and false question?
D. Unbalanced forces are acting on it.
hope this helped
Answer:
True. Gold does have a higher density than tin
Rutherford is credited for discovering the nucleus of the atom. This occurred after he performed his famous gold foil experiment - by exposing a source of alpha particles to a gold foil to see how the particles deflected against the atoms of the foil, he discovered that the observed pattern only made sense when he considered the idea of a nucleus in this situation.
When force is applied on an object the object will not slide
So here object will remain in equilibrium after applying the force
So in this case the condition of equilibrium is maintained due to friction force that is applied on the object.
So here for equilibrium be can say

also we know that

we are given that
( applied force on the box)


So here this friction force on the cart is known as static friction
