A cart is rolling across the floor at a constant velocity of 2 m/s to the right. The cart is pushed again to the right, and it starts to speed up.

How are the force of the push and speed of the cart related?
A.
The balanced push causes the cart to speed up.
B.
The unbalanced push causes the cart to speed up.
C.
The force and speed are not related.
D.
The force of gravity makes the cart speed up.

B. The unbalanced push causes the cart to speed up.