Project

Q1 :

PE @ 90m = mgh = 1.2*9.81*90 = 1059.48J

@V , KE = 3 *PE

on calculating the free fall velocity which is a constant acceleration we get V = 42.021m/s .

on calculating the height H @V = v^2 / 6g = 30m

Q2:

Q = k *A* detaT

Applying series equivation of thermal conductivity and calculating the same . we get k = 0.1034Wm-1°C-1.

Q = k A (T2 - T1 )/ L

Q = 1571W of Power the heater must give to heat the room to 22degC .

Q3 :

This is a wheat stone bridge circuit , there is no current flowing through 5ohm resistor . Hence the 50ohm resistance can be neglected.

Equivalent resistance = 20ohm.