Use the figure for the question. The graph shows the speed of a light truck of mass 4000 kg coasting on neutral down a level straight road.The truck is slowing down due to air resistance and rolling friction.
-The net force at 25s is ____ the net force at 5s.
A)less than
B)equal to
C)greater than
D)unable to tell
E)depends on what the acceleration is

Question

Use the figure for the question. The graph shows the speed of a light truck of mass 4000 kg coasting on neutral down a level straight road.The truck is slowing down due to air resistance and rolling friction. 
-The net force at 25s is ____ the net force at 5s.
A)less than 
B)equal to 
C)greater than 
D)unable to tell 
E)depends on what the acceleration is

Quizplus · Accepted Answer

As per Newton's first law of motion, if no external force is applied on an object, its velocity will remain constant. From the graph, we can see that the speed of the truck is decreasing, which means that there must be some external force acting on it. This force is the net force, which is the sum of all the forces acting on the truck. As the truck is slowing down, the net force is decreasing with time. Therefore, the net force at 25s is less than the net force at 5s. Hence, the best choice is A) less than.

Use the Figure for the Question