Agardener pushes a 20 kg lawnmower whose handle is tilted up 37∘ above horizontal. the lawnmower's coefficient of rolling friction is 0.18. how much power does the gardener have to supply to push the lawnmower at a constant speed of 1.5 m/s ? assume his push is parallel to the handle.

58.4 W

Explanation:

The speed of the lawnmower is constant: this means that its acceleration is zero, so the net force on it is zero.

The equation of the forces along the two directions therefore are:

- Perpendicular to the floor:

- Parallel to the floor:

where

F is the push of the gardener

R is the normal reaction

m = 20 kg is the mass

g = 9.8 m/s^2 is the acceleration of gravity

is the coefficient of friction

Solving for R,

Substituting into the other equation,

And the power he must supply therefore is the product of this force and the speed:

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