A chisel plow with 7 tines spaced $30\text{ cm}$ apart penetrates to a depth of $25\text{ cm}$. If the specific soil resistance is $0.5\text{ kg/cm}^2$ of projected frontal area of tines (each tine width is $5\text{ cm}$), calculate the total draft force in $\text{N}$. (Take $g = 9.81\text{ m/s}^2$)
Answer Key:
4291.88
Step-by-Step Solution & Explanation
Frontal projected area of each tine:
$A_1 = \text{width} \times \text{depth} = 5\text{ cm} \times 25\text{ cm} = 125\text{ cm}^2$
For 7 tines:
$A_{\text{total}} = 7 \times 125 = 875\text{ cm}^2$
Draft in $\text{kgf}$:
$D = A_{\text{total}} \times 0.5 = 875 \times 0.5 = 437.5\text{ kgf}$
Draft in Newtons:
$D_N = 437.5 \times 9.81 = 4291.88\text{ N}$