Question

A woman pushes a lawn mower with a constant force of 112 Newtons at an angle of 37◦ with respect to the horizontal. The lawn mower moves at a speed of 20 cm/sec. What is her power output? (1 hp = 746 Watts)

1. 0.024 hp
2. 0.030 hp
3. 0.020 hp
4. 0.040 hp
5. 0.044 hp
6. 0.034 hp

Answer 1

1.0.024 hp

Explanation:

We are given that

Constant force=F=112 N

`\theta=37^(\circ)`

Speed of lawn mower,v=20 cm/s=
`20* 10^(-2) m/s`

1 m=100 cm

1 hp=746 watt

We have to find the power output

Force applied by women on lawn mower=
`Fcos\theta=112cos 37^(\circ)`

Force applied by women on lawn mower=
`89.45`N

Power output,P=
`Fv`

Using the formula

Power output=
`89.45* 20* 10^(-2)=17.89 watt`

Power output,P=
`(17.89)/(746)=0.024`hp

Hence, option 1 is true