Examination 1

An electric heater has a power rating of 1500 Watts (1.5 kW). If the heater is run for 6 hours, and electricity costs $0.12 per kWh, how much will it cost to run the heater for this time interval?

$1.05

If a net force of 30 Newtons is applied to a car of mass 3 kg initially at rest, the velocity of the cart at the end of 5 meters will be ______m/s

10 m/s

A household furnace has an output of 100,000 Btu/hr. What size electrical heating unit (in kW) would be needed to replace this?

29.3 kW

If I drop a stone from a bridge that is 30 m above the water, how long will it take until the stone hits the water? (Hint, estimate KE and PE and equate them to proceed further)

3 seconds

The maximum efficiency of a heat engine operating between 2 C and 200 C will be about ______

40%

The cost of running a set of eight 100 way light bulbs for 6 hours, with the cost of electricity at 9 cents per kWh is approximately...

43 cents

How much work is required to increase the velocity of a 4 kg car from rest to 5 m/sec?

50 Joules

For fossil fueled electrical generating plant, 10,000 Btus of chemical energy input into the plant will result in about how many Btus of waste heat dumped into the environment?

6,000 Btus

A ball of mass 0.5 kg is dropped from a height of 5m. WHat is the greatest velocity it will have just before hitting the ground?

9.9 m/s

Power?

= Work/Time = Idk..Asher got this wrong

If a constant non-zero net force is applied to an object, its velocity will certainly...?

Change

List 3 non-renewable resources

Fossil fuels, coal, oil shale

The "efficiency" of a light bulb is the ratio of the:

Light output to the electrical input

Skip this one

Skip

An object with a high specific heat will:

Take considerably more heat to raise its temperature

Which of the following is a non-renewable resource?

Uranium

If it takes 2 seconds to raise an 8 kg block a vertical height of 1 m, what is the power expended?

W = F x D. = 8000

What color would you select for a container holding ice cubes such that the ice is preserved the longest?

White

List 3 renewable resources

Wind power, solar power, geothermal energy

A heat engine _____

needs a temperature difference to be able to work

Which of the following situations would be allowed by the second law of thermodynamics?

running of a heat engine using temperature differences in the oceans