- #1

danago

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## Homework Statement

A lawnmower weighing 20kg has a handle attached at 35 degrees to the horizontal. If a man wishes to push the lawnmower, so that after 2.5s, its velcoity is 2 m/s, what force should he apply along the handle.

## Homework Equations

[tex]

\sum {\overrightarrow F } = m\overrightarrow a

[/tex]

## The Attempt at a Solution

ok, since after 2.5 seconds, it requires a velocity of 2 m/s, i found the acceleration of the mower to be 0.8 m/s/s. Since it has a mass of 20kg, the net force applied must then be:

[tex]

\sum {\overrightarrow F } = 20 \times 0.8 = 16N

[/tex]

So the horizontal component of the force he applies must be 16N in the direction of acceleration.

The horizontal component of the force (F) he applies down the handle will be [tex]F cos 35[/tex]. So solving for F:

[tex]Fcos35=16[/tex]

Gives F=19.5N.

According to the answer book, the answer is 120N. Where have i gone wrong?

Thanks,

Dan.

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