## anonymous one year ago four machines (A-D) push four identical heavy boxes 100 m along a track. According to the graph, which machine pushed with the greatest force? Machine A, machine B, machine C, machine D, or all pushed with the same force?

1. anonymous

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2. Michele_Laino

we have this general relationship, between power P, force F and velocity v: $\Large P = {\mathbf{F}} \cdot {\mathbf{v}}$

3. anonymous

ok!

4. Michele_Laino

that is a vector equation. Now if velocity and Force have the same orientation and direction, we can write: $\Large P = Fv$

5. anonymous

yes!

6. Michele_Laino

that equation, in the plane P-v represents a line whose slope is the force F

7. anonymous

so mahcine A is the solution here?

8. Michele_Laino

that's right!

9. anonymous

yay~ thanks!!

10. Michele_Laino

:)