110 Answered Questions for the topic Energy

01/09/16

Define Energy

Dear teacher People say : energy is the ability to do work But then" what is work ?" I asked : they said " work is energy tranfered by force " Bla , they use energy to define work and work to... more
Energy Physics Work Slide

11/13/15

two mass connected by string on a slide... about the work and energy things

There a mass of 4kg and a mass of 5kg connected by an inextensible string passing over a smooth pulley .the mass for 4kg starts from rest and moves up the smooth plane inclined at 30degree to... more

11/10/15

Quick Science Question: Calculating Thermal Energy?

A model rollercoaster car weighs 3 kg. If it reaches 5 meters, how much energy is transformed into thermal energy at that point?  I have other values too (it's a multiple part... more

11/02/15

A 45.2kg boulder falls off a mountain that is 255 m tall. What is the kinetic energy of the boulder when it falls off the cliff?

I know the answer might be 0J but I need help explaining how to get the answer

10/30/15

A particle with total energy E in Potential energy region U(x).Motion of the particle is restricted to the region when ? check description

A particle with total energy E in Potential energy region U(x).Motion of the particle is restricted to the region when  options are (a) U(x)>E (b) U(x)<E (c) U(x)=0 (d) U(x) < or = E

10/30/15

Car have mass m,its engine delivers power P.what's the minimum time in which car can be accelerated from rest to speed v

A car of mass m has an engine which can deliver power P.The minimum time in which car can be accelerated from rest to a speed v is(a) (mv^2)/2P(b) Pmv^2(c) 2Pmv^2(d) (mv^2)P/2
Energy Work Power

10/30/15

Find mechanical power?

The blades of a wind mill sweep out a circle of area A.If wind flows with velocity v perpendicular to blades of wind mill and its density is D,then the mechanical power received by wind mill is (a)... more
Energy Work Power

10/30/15

Find Power ?

A pump is used to pump a liquid of density D continuously through a pipe of cross section area A.If liquid is flowing with speed v,then power of pump is(a) (DAv^2)/3(b) (DAv^2)/2(c) 2DAv^2(d)... more

07/22/15

Physics: What are the following for this system: amplitude, frequency, period, spring constant, max velocity and total energy?

A 27.8 gram mass oscillates on the end of a spring and its motion can be described by: (1.5 )sin (21.4 t ) [here the units are standard, meters and seconds]   What are the following for this... more

07/15/15

Physics: amplitude, frequency, period, spring constant, max velocity and total energy

A 27.8 gram mass oscillates on the end of a spring and its motion can be described by: (1.5 )sin (21.4 t ) [here the units are standard, meters and seconds] What are the following for this system:... more

07/10/15

Physics: Thermodynamics (ice)

If a 0.06247 kg ice cube initially at 0.00 C is allowed to melt in a Styrofoam cup holding 0.497 kg of water at 10.0 C , what is the total entropy change for this process?

07/06/15

Physics: Change in internal Energy

2.50 moles of an ideal monatomic gas are compressed from 315,000 Pa to 175,000 Pa at 0.0300 m3. What is the change in internal energy in this isochoric process?
Energy Physics Speed

06/11/15

a spring of force constant 200N/m is compressed through a distance of 0.05m calculate the energy stored in the string

 I.calculate the energy stored in the string II.if the energy in (I.) above is imparted to a body of mass 0.5kg to set it in motion calculate the speed acquired by the body
Energy

05/04/15

How much energy in kilocalories(kcal) would combustion of 0.420 ounces of methane release?

The combustion of 45.0g of methane (natural gas) releases 2498 kJ of heat energy. How much energy in kilocalories(kcal) would combustion of 0.420 ounces of methane release?

05/03/15

Ideal gas, potential energy help

Let us consider an ideal gas in a gravitational field which is uniform with strength g. The gas is trapped in a highly realistic h=10km vertical column of height h with perfectly insulating walls.... more

Physics-Energy/ conservation of energy

Question: At a water park, Hugo climbs a 15.00m springboard, in 22.00s, to execute his famous THUNDER CANNON BALL. Hugo jumps up at 6.000m/s [up] off the end of the diving board and propels his... more

What is the energy transfer of a battery rolling out of a rolling cup?

A cup is on its side. inside the cup is a double A battery. An object hits the cup forcing the cup to roll. As the cup rolls the batter rolls out. What is the energy transfer of the battery rolling... more

Calculate the energy cost (kWh/p/d)

Australia produces 20 megatonnes (Mt) of alumina every year, where each tonne requires 3.8 MWh of heat energy to produce. Calculate the energy cost (kWh/p/d) to produce alumina spread across the... more

11/03/14

The Rydberg Equation and Ionization Energy

I'm not sure where to begin. I really need some help on this one.  I have the Rydberg equation here but I have no idea how to use the answer from the equation and use it to find the second... more

10/21/14

How do plants store and use energy?

How do plant cells store energy? Also, how do plant cells use the energy?

Express your answer in units of kWh/d.

Chickens require 0.075 kWh per day of energy (as feed) for each kilogram of animal, and 2/3 of an adult chicken is edible meat. The lifespan of a chicken is 50 days.What is the daily energy... more
Energy Physics

10/14/14

roller coaster energy problem

A roller coaster starts from rest at the top of a hill with 1000J of potential energy. How much kinetic energy does it have? How much total mechanical energy?  (KE + PEg + PEs) How much... more

Express your answer as a percentage.

Typical fresh water usage is approximately 150 litres per day per person. If all of this water came from a desalination plant with an energy cost of 4 kWh(e)/m3 what percentage would this be of the... more

Express your answer in terms of W/m2.

What is the average power per m2 of floor space for a 100 m2 apartment with a leakiness (heat-loss coefficient) of 9 kWh per day per oC and an average inside/outside temperature difference of 15oC.... more

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