An object travels North at #4 m/s# for #5 s# and then travels South at #9 m/s# for # 2 s#. What are the object's average speed and velocity?

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Answer 1 · 2018-01-14T16:36:13

Average speed = #5.42 m/s#
Average velocity = #0.28 m/s#

We know that average speed = total distance covered/total time taken.

So,total distance covered in this case in 7 seconds is #(4*5)+(9*2)# meters or, 38 meters,hence average speed is #38/7# #m/s# or, #5. 42 m/s#

Now,avergae velocity = total displacement/total time taken

Here,the object has gone #20 #meters to north and #18# meters to south,hence displacement = #(20-18) m or 2 m# (taking towards north to be positive)

Hence average velocity is #2/7 m/s# or, #0.28 m/s#

Answer 2 · 2018-01-14T16:55:09

velocity=#2/7m/s#
speed=#5.4m/s#

my own work.