Tea Water Heater Electric
Posted on Sunday, February 27th, 2011 at 6:39 pm
please help me on physics?
I need help on these two problems.i cant find the formulas in the book and it just doesn’t make sense to me. can anyone help me solve these?
1) Think about using the conversion of gravitational potential energy to thermal energy in order to heat water for showers. Assume that 1.0L of water(or 1000g of water). initially at 12.7 celsius falls over a 50m waterfall. if all the potential energy of the water is converted to kinetic energy as the water is falling, and the kinetic energy is converted into thermal energy when it reaches the bottom, wat temp. difference exists btwn the bottom and the top of the waterfall? Will this be sufficient to produce a warm shower?
2) An electric immersion heating coil is used to bring 90.0mL of water to a boil, for a cup of tea. if the immersion heater is rated 200W, find the time needed to bring this amount of water, initially at 21 celsius to the boiling point.
1) You know to know that 4.2 x 10^3 joules of any kind of energy is needed to raise the temperature of 1 kg of water by I˚ C
Energy delivered by the falling water = m . g . ∆h = 1 . 9.8 . 50 = 490 Joules
Heat energy produced = 490 J = m . sp ht . temp rise
490 = 1 . 4.2 . 10^3 . temp rise
temp rise = 0.116 = 0.12˚C
2) Heat needed = m . sp ht . ∆t = 90 . 10^–3 . 4.2 . 10^3 . 79 = 29862 J
200 W = 200 joules per second so the time taken to supply the required heat = 29862 / 200
= 149.3 s = 150 s = 2 and a half minutes.
For Sale! Home plus 80 wooded acres in Minnesota!
|
|
Aroma AWK-115S Hot H20 X-Press 1-1/2-Liter Cordless Water Kettle $30.99 The Hot H20 X-Press from Aroma provides boiling water in a matter of minutes. The 1.5-liter capacity is ideal for a variety of uses–hot tea, soups, instant coffees, oatmeal, hot chocolate, noodles, baby formula and more. Once water reaches a boil, the kettle will automatically shut off and lifts off its base for easy, cord-free pouring. The beautiful polished stainless steel finish looks great … |
|
|
Cuisinart CPK-17 PerfecTemp 1.7-Liter Stainless Steel Cordless Electric Kettle $79.99 This Cuisinart Perfectemp Cordless Electric Programmable Kettle offers latest innovation for this product category%2E Heating water will never be easier with this handsome brushed stainless steel kettle%2E Great for making tea%2C hot chocolate or instant soups%2E It will quickly bring 1%2E75 quarts of water to a boil and then turn itself off%2E… |
|
|
Proctor Silex K2070Y 1 Liter Electric Kettle $11.39 Housed in a smooth, modern-looking design, this 1000-watt electric kettle rapidly boils up to 1 quart of water for coffee, tea, instant soups, and more. The unit features a detachable cord and a nonspill spout for graceful serving, plus a generous handle with a secure grip. Its immersed heating element provides a rapid and quiet heating process, making it ideal for the office, home, or college dor… |
|
|
NEW TIGER PDNA30U WATER HEATER 3 LITER – PDN-A30U $135.45 TIGER PDNA30U WATER HEATER 3 LITERTIGER PDNA30U WATER HEATER 3 LITER:… |
|
|
Helen Of Troy Hotspa Professional Ultimate Foot Bath $65.88 Ozone (active oxygen) helps to control, reduce and eliminate bacteria Motorized Pedicenter rotates with the press of a foot. Three interchangeable massage attachments: * Pumice stone exfoliates feet Aromatherapy Dispenser – Add essential oils or dissolving scent bea… |
|
|
Roadpro 12V Hot Pot, 20 oz. $11.27 - Plugs Directly into Your Cigarette Lighter Socket – Outer Lid Can be Used as a Cup – Inner Lid Closes Securely to Prevent Spilling… |
|
|
RoadPro RPBH-012 12V Beverage Heater $6.70 Roadpro 12-volt Beverage Heater – Roadpro RPBH-012…. |
|
|
RoadPro 5027S 12V Smart Car Pot $18.90 Roadpro 12-volt 20oz. Smart Car Pot – Roadpro 5027S…. |
|
|
Travel Immersion Water Heater – Dual Voltage $17.50 Lightweight heating coil comes with its own travel pouch. Burn shield protects counters. Great for travel – makes coffee or tea…. |
|
|
European Travel Water Heater $60.00 Portable Kettle features European round adapter plug as well as the optional U.S adapter plug included…. |
