Posted by Mandy on Tuesday, January 19, 2010 at 6:58pm.
Let the distance from A to B (in meters) be L.
The total distance travelled is then 2L
The times spend going back and forth are L/20 and L/25 s.
Divide 2L by [L/20 + L/25] for the average speed. Note that the L cancels out.
Vav = 2/[1/20 + 1/25]
= 2/(9/100) = ___ m/s
Note that the average speed Vav is NOT the average of the two speeds.
Instead, 1/Vav = (1/2)[1/V1 + 1/V2]
Related Questions
college physics - A car is driven from point A to B at a constant speed of 25.0 ...
physics - A person walks first at a constant speed of 4.90 m/s along a straight ...
physics - A person walks first at a constant speed of 4.90 m/s along a straight ...
physics, dynamics - Car A starts from rest at t = 0 and travels along a straight...
physics - A person walks first at a constant speed of 4.70 m/s along a straight ...
physics - A person walks first at a constant speed of 4.50 m/s along a straight ...
Physics - A roller coaster car of mass 1000kg is riding along a track from point...
physics - Cars A and B are racing each other along the same straight road in the...
physics - Cars A and B are racing each other along a straight path in following ...
physics - Cars A and B are racing each other along a straight path in following ...
For Further Reading
