Question

The question i was given is: About how much pressure do the feet of a 6000-kg elephant exert on the ground? Assume each foot has an area of 0.10 square meter. Please show all your work.
so, i need to use the pressure formula p=force/area of application but, don't i need to convert the 6000kg in newtons first? how exactly would i go about doing that?

Answer 1

Yes, you need to convert the mass into weight first. The weight of the elephant is:
$W=mg = (6000 kg)(9.81 m/s^2)=5.89 \cdot 10^4 N$
This is the force that pushes on the ground. The total area on which this force is acting is 4 times the area of each foot (because the elephant has 4 feet), so the total area is:
$A=4 \cdot 0.10m^2 = 0.40 m^2$
And so, the pressure exerted by the feet of the elephant on the ground is
$p= \frac{F}{A} = \frac{5.89 \cdot 10^4 N}{0.40 m^2}=1.47 \cdot 10^5 Pa$