Connected rates of change?
A watermelon is assumed to be spherical in shape while it is growing. Its mass M kg , and radius r cm , are related by the formula M = kr^3 , where k is a constant. It is also assumed that the radius is increasing at a constant rate of 0,1 cm per day. On a particular day the radius is 10 cm and the mass is 3,2kg . Find the value of k and the rate at which the mass is increasing on this day.
A watermelon is assumed to be spherical in shape while it is growing. Its mass
1 Answer
Aug 3, 2017
Explanation:
M=kr^3
"given "r=10" and "M=3.2
rArrk=M/r^3=3.2/1000=2/625
(dM)/dt=(dM)/(dr)xx(dr)/dtlarr" chain rule"
"where "(dM)/(dr)=3kr^2" and "(dr)/dt=0.1
rArr(dM)/dt=3xx2/625xx(10)^2xx0.1
color(white)(rArr(dM)/dt)=0.096" Kg/day"