An object moves 10.0 m east in 10.0 s and then returns to its starting point taking an additional 40.0 s.If west is chosen as the positive direction,what is the average speed of the object?
A)0.4 m/s
B)-0.4 m/s
C)10.0 m/s
D)0 m/s
E)-10.0

Question

An object moves 10.0 m east in 10.0 s and then returns to its starting point taking an additional 40.0 s.If west is chosen as the positive direction,what is the average speed of the object?
A)0.4 m/s
B)-0.4 m/s
C)10.0 m/s
D)0 m/s
E)​-10.0

Quizplus · Accepted Answer

The total distance covered by the object is twice the distance it covered in the first 10.0 s, which is 20.0 m. The total time taken is 10.0 s + 40.0 s = 50.0 s.

Average speed = total distance ÷ total time 
= 20.0 m ÷ 50.0 s 
= 0.4 m/s

Since west is taken as the positive direction, the negative sign is not used in the answer.

An Object Moves 10