A1500 w portable heater is needed to replace the heat lost through a circular window (radius 25 cm) in the wall of a home that is made of a single pane of glass 0.30 cm thick. thermal conductivity for the glass is 0.63 w/mk. the temperature inside the house is 20°c and outside is -12°c. what is the thickness of the window?

The thickness of the window pane is 2.94 mm

Solution:

As per the question:

Power of the heater, P = 1500 W

Thickness of the glass pane, t = 0.30 cm =

Radius, R = 25 cm = 0.25 m

Thermal Conductivity of glass, K = 0.63 W/ mK

Inside Temperature,

Outside Temperature,

Now,

Power of the heater = Heat Loss, Q

Thus

Q = 1500 W

We know that:

t' = 2.94 mm

i would say

initial speed when it is dropped is 150 ft/s

now at the same moment the acceleration due to gravity is perpendicular to its velocity

so as we know that

now we have centripetal acceleration a = 32 ft/s^2 as its perpendicular to velocity

while tangential acceleration at the same moment will be zero

so

now radius of curvature is given as

so the radius of curvature just after it is dropped is 703.125 ft