EMGT 3113 Test 1 Questions With Correct
Answers
discuss the transformation of potential energy of water as it flows
| | | | | | | | | | |
behind a dam as it flows through a pipe at the bottom of a turn
| | | | | | | | | | | | | | |
generator - CORRECT ANSWER✔✔-the water transforms from potential
| | | | | | | |
energy to kinetic energy as it flows to the bottom of the generator, the
| | | | | | | | | | | | | |
flowing water turns on the generator which creates mechanical energy,
| | | | | | | | | |
which then converts mechanical energy into electric energy as the
| | | | | | | | | |
generator produces electricity| |
refer to the the discussion of energy losses in a car. what are some ways
| | | | | | | | | | | | | | |
to increase the fuel economy of a car? - CORRECT ANSWER✔✔-1. the
| | | | | | | | | | | |
speed must be kept from 40-50 mph to increase the fuel economy of a
| | | | | | | | | | | | | |
car
2. a decrease in the use of cars
| | | | | | |
3. reduction of emission of greenhouse gases from the burning of fuel
| | | | | | | | | | | |
4. reduction in gasoline consumption
| | | |
categorize the following units as of work or power: joules, watts, kilo-
| | | | | | | | | | |
watt hours, ft-lb, calories, kW, ft-lb/min. - CORRECT ANSWER✔✔-Work:
| | | | | | | | |
Joule, ft-lb, calorie, Kilo-watt hour
| | | |
Power: ft-lb/min, kW, watts
| | |
, how much work do expend to move a 450lb fridge 6 feet across the
| | | | | | | | | | | | | |
floor while exerting a force of 90lbs? - CORRECT ANSWER✔✔-W=FxD
| | | | | | | | |
so 90lbs x 6 feet = 540 ft-lbs
| | | | | | |
a 100watt lightbulb is accidentally left on for 2 days, if electricity cost 12
| | | | | | | | | | | | | |
cents/kWh, how much did this oversight cost? - CORRECT ANSWER✔✔- | | | | | | | | |
So,
Step 1: 100W x 48hours = 4800Wh
| | | | | | |
Step 2: (1kWh/1,000Wh)= .001
| | |
Step 3: .001 x 4800Wh = 4.8Kwh
| | | | | |
Step 4: So 4.8kWh x 12 cents/Kwh
| | | | | | |
= 57.6 cents
| |
Suppose the overall efficiency for the conversion of the chemical energy
| | | | | | | | | | |
of coal into the useful mechanical work of an electric motor is 29%. If
| | | | | | | | | | | | | |
the efficiency for the production of electricity is 35% and the efficiency
| | | | | | | | | | | |
for its transmission to the motor is 85%, then what is the efficiency of
| | | | | | | | | | | | | |
the motor itself for conversion from electrical to mechanical energy? -
| | | | | | | | | | |
CORRECT ANSWER✔✔-So, |
.35x x .85x = .29| | | |
.35x.85=.2975x
.29/.2975=.9748
Answers
discuss the transformation of potential energy of water as it flows
| | | | | | | | | | |
behind a dam as it flows through a pipe at the bottom of a turn
| | | | | | | | | | | | | | |
generator - CORRECT ANSWER✔✔-the water transforms from potential
| | | | | | | |
energy to kinetic energy as it flows to the bottom of the generator, the
| | | | | | | | | | | | | |
flowing water turns on the generator which creates mechanical energy,
| | | | | | | | | |
which then converts mechanical energy into electric energy as the
| | | | | | | | | |
generator produces electricity| |
refer to the the discussion of energy losses in a car. what are some ways
| | | | | | | | | | | | | | |
to increase the fuel economy of a car? - CORRECT ANSWER✔✔-1. the
| | | | | | | | | | | |
speed must be kept from 40-50 mph to increase the fuel economy of a
| | | | | | | | | | | | | |
car
2. a decrease in the use of cars
| | | | | | |
3. reduction of emission of greenhouse gases from the burning of fuel
| | | | | | | | | | | |
4. reduction in gasoline consumption
| | | |
categorize the following units as of work or power: joules, watts, kilo-
| | | | | | | | | | |
watt hours, ft-lb, calories, kW, ft-lb/min. - CORRECT ANSWER✔✔-Work:
| | | | | | | | |
Joule, ft-lb, calorie, Kilo-watt hour
| | | |
Power: ft-lb/min, kW, watts
| | |
, how much work do expend to move a 450lb fridge 6 feet across the
| | | | | | | | | | | | | |
floor while exerting a force of 90lbs? - CORRECT ANSWER✔✔-W=FxD
| | | | | | | | |
so 90lbs x 6 feet = 540 ft-lbs
| | | | | | |
a 100watt lightbulb is accidentally left on for 2 days, if electricity cost 12
| | | | | | | | | | | | | |
cents/kWh, how much did this oversight cost? - CORRECT ANSWER✔✔- | | | | | | | | |
So,
Step 1: 100W x 48hours = 4800Wh
| | | | | | |
Step 2: (1kWh/1,000Wh)= .001
| | |
Step 3: .001 x 4800Wh = 4.8Kwh
| | | | | |
Step 4: So 4.8kWh x 12 cents/Kwh
| | | | | | |
= 57.6 cents
| |
Suppose the overall efficiency for the conversion of the chemical energy
| | | | | | | | | | |
of coal into the useful mechanical work of an electric motor is 29%. If
| | | | | | | | | | | | | |
the efficiency for the production of electricity is 35% and the efficiency
| | | | | | | | | | | |
for its transmission to the motor is 85%, then what is the efficiency of
| | | | | | | | | | | | | |
the motor itself for conversion from electrical to mechanical energy? -
| | | | | | | | | | |
CORRECT ANSWER✔✔-So, |
.35x x .85x = .29| | | |
.35x.85=.2975x
.29/.2975=.9748
