An object is moving along a straight line. The graph shows the object's position from the starting point as a function of time.

-What was the instantaneous velocity of the object at t = 4 s?
A)+6 m/s
B)+8 m/s
C)+10 m/s
D)+20 m/s
E)+40 m/s

Question

An object is moving along a straight line. The graph shows the object's position from the starting point as a function of time.

-What was the instantaneous velocity of the object at t = 4 s?
A)+6 m/s 
B)+8 m/s 
C)+10 m/s 
D)+20 m/s 
E)+40 m/s

Quizplus · Accepted Answer

The instantaneous velocity at any point on a position-time graph is given by the slope of the tangent line to the graph at that point. At t = 4 s, the tangent line is nearly horizontal, passing through the point (4, 45). The slope of this line is approximately 10 m/s, so the instantaneous velocity at t = 4 s is +10 m/s. Therefore, the correct answer is choice C.

An Object Is Moving Along a Straight Line