Assume that a spherical rain drop evaporates at a rate proportional to its surface area. Form a differential equation involving the rate of change of the radius of the rain drop.

A spherical rain drop evaporates at a rate proportional to its surface area at any instant tdot The differential equation giving the rate of change of the radius of the rain drop is _____

Assume that a spherical rain drop evaporates at a rate proportional to its surface area. Form a differential equation involving the rate of change of the radius of the rain drop.

Spherical rain drop evaporates at a rate proportional to its surface area. The differential equation corresponding to the rate of change of the radius of the rain drop if the constant of proportionality is K >0 is (a) ( b ) (c) (d)(( e ) dy)/( f )(( g ) dt)( h ) (i)+K=0( j ) (k) (b) ( l ) (m) (n)(( o ) d r)/( p )(( q ) dt)( r ) (s)-K=0( t ) (u) (c) ( d ) (e) (f)(( g ) d r)/( h )(( i ) dt)( j ) (k)=K r (l) (m) (d) None of these

A right circular cone with radius R and height H contains a liquid which evaporates at a rate proportional to its surface area in contact with air (proportionality constant k is positive). Suppose that r(t) is the radius of the liquid cone at time t. The time after which the cone is empty is

n a test experiment on a model airplane in a wind tunnel, the flow speeds on the upper and lower surfaces of the wing are 70 m s-1 and 63 m s-1 respectively. What is the lift on the wing if its area is 2.5 m2 ? Take the density of air to be 1.3 kg m-3.

A pitcher with 1-mm thick porous walls contain 10kg of water. ,Water comes to its outer surface and evaporates at the rate of 0.1gs^(-1) . The surface area of the pitcher (one side) =200cm^(2) . The room temperature =42^(@)C , latent heat of vaporization =2.27xx10^(6)Jkg^(-1) , and the thermal conductivity of the porous walls =0.80js^(-1)m^(-1)C^(-1) . Calculate the temperature of water in the pitcher when it attains a constant value.