A student walks from her apartment a distance d=139m to the bus stop at a speed of v1= 1.40m/s. The she realizes that she has forgotten her crib sheet for her exam and so runs back to her apartment to pick it up and returns to the bus stop at a speed v2= 4.80m/s. What is her average velocity.

Question

A student walks from her apartment a distance d=139m to the bus stop at a speed of v1= 1.40m/s. The she realizes that she has forgotten her crib sheet for her exam and so runs back to her apartment to pick it up and returns to the bus stop at a speed v2= 4.80m/s. What is her average velocity.

The equation I always end up with is 417m/157.202s which gives me 2.65263 rounding to 2.65m/s which is not the right answer

Answer 1

Her DISTANCE was 417

BUT

Her DISPLACEMENT was 139

going to the stop and back is a displacement of zero

You calculated SPEED not VELOCITY , falling for their trick.

she moved 139 meters in your 157.202 seconds (I assume you did that right :)