Project
Quest 1 :
| m | 1.2 | kg | ||
| KE | 3 x PE | |||
| 0.5mv^2 | 3 mxgxh | |||
| Energy at rest [E] | U | 1.2*9.81*90 | 1059.48 | J |
| KE + PE = E | ||||
| 3*mgh+mgh = E | ||||
| 4*mgh = E | ||||
| h | E/(4*mg) | |||
| = 1059.48/(4*1.2*9.81) | ||||
| 22.5 | m | |||
| Ans : The point V is 22.5 m above the surface | ||||
Quest : 2
| Quest2 | ||||||||
| romm temp | 22 | C | T1 | T'1 | ||||
| Wall Area | 140 | m2 | T'2 | |||||
| Outside Temp | -10 | C | T2 | |||||
| Matrl 1 | 2.5 | cm | x1 | |||||
| Matrl 2 | 2 | cm | x2 | |||||
| Matrl 3 | 25 | cm | x3 | |||||
| Total thickness | 29.5 | cm | X' | |||||
| Thermal cond x1 | 0.125 | Wm-1C-1 | kw | |||||
| Thermal cond x2 | 1.5 | Wm-1C-1 | kc | |||||
| Thermal cond x3 | 1 | Wm-1C-1 | kb | |||||
| delQ/Del T | kw * A * (T1-T'1) / x1 | = | kc * A *(T'1 - T'2)/ x2 | = | kb*A*(T'2-T2)/ x3 | |||
| 0.125(22-T'1)/(2.5*0.01) | 1.5*(T'1-T'2)/(2*0.01) | 1*(T'2+10))/(25*0.01) | ||||||
| 110 | -5T'1 | = | 75T'1 -75T'2 | = | 4T'2+40 | |||
| 85T'1-75T'2-110 = 0 | Eq. 1 | |||||||
| 75T'1-79T'2-40 = 0 | Eq.2 | |||||||
| T'1 = (79T'2+40) / 75 | ||||||||
| Sub Eq. 2 in Eq . 1 | ||||||||
| 89T'2+45-75T'2-110 = 0 | ||||||||
| 14T'2 =65 | ||||||||
| T'2 | 4.64285714 | |||||||
| T'1 | ((79*4.643)+40)/75 | |||||||
| T'1 | 5.42396 | |||||||
| DelQ/DelT | 0.125*140*(22-5.4)/0.25 | |||||||
| 1162 | W/m2 | |||||||
| Area | 140 | m2 | ||||||
| For the given area a power required is 1162*140 | 162680 | W | ||||||
| In Watts per hour, the heater is required to have a power of 16280/60 | 271.3333 | W | ||||||
Quest 3 :
| 15 | Parallel | =((1/15)+(1/30))^-1 | 10 | |||||||
| 30 | Series | =10+50+10 | 70 | ohm | ||||||
| 50 | ||||||||||
| 15 | Parallel | =((1/15)+(1/30))^-1 | 10 | |||||||
| 30 | ||||||||||
| Ans | The eq. Resistance value is 70 ohm | |||||||||