Leah watches a toy car move across a table at a constant speed. The car moves across the table in one direction and falls off th
e other side. Leah decides to try another situation. She watches the car move across the table at a constant speed, then when it reaches the other side of the table, her friend Joey pushes the car in the other direction. The car moves back to Leah. Based on Leah's informal experiment, what forces cause the car to change direction?
A.
balanced forces from Joey pushing the car
B.
unbalanced forces from Joey pushing the car
C.
unbalanced forces from Leah watching the car
D.
balanced forces from the car moving across the table
In order to change the direction and speed, a net external force is required. A net external force is an unbalanced force which will change the direction and gives the speed in the opposite direction. Hence, its an unbalanced force from the joey that pushes the car in the other direction due to which it the car starts to move back to Leah. Without, unbalanced force there is not change in the direction of the car's motion.
