15.A force of 3.00 N is applied to a spring whose elastic constant is 0.20 N/cm. Its change in length is?

Question

1. A 0.4 kilogram sample of Aluminum at 100 degrees Celsius is put into a container containing 0.5 kilograms of water at 20 degrees Celsius. Neglecting the small amount of energy absorbed by the container and knowing the specific heat of Aluminum 900 kJ/kg*C is and the specific heat of the water is 4186 kJ/kg*C answer the following question. Compared to the heat liberated by the aluminum, the heat absorbed by the water is…

2. Be able to read a phase diagram and tell what the boiling point temp is and the freezing point temp, specific heat of each phase, Latent Heat of Vaporization.

3. What happens to the average kinetic energy of molecules as you heat a substance? As you cool it?

4. An unknown solid with a mass of 2.00 kilograms remains in the solid state while it absorbs 75.0 kilojoules of heat. Its temperature rises 15.00 degrees Celsius. What is the specific heat of the unknown solid?

5. A car with mass M traveling at speed V has kinetic energy K. What is the kinetic energy of a second car that has twice the mass M and twice the speed of the first car?

6. A pendulum has a mass of 15kg and its kinetic energy is 400 Joules at the base of the swing. What is the pendulums velocity?

7. A ball at the top of its drop has 15 J of potential energy, neglecting air resistance, what is the kinetic energy at the bottom of the drop? What is the velocity?

8. Sam does 100 J of work Monday , on Tuesday she does 100 J of work in half the time it took her on Monday. Tuesday her power increased, decreased or stayed the same in comparison to Monday?

9. What is the work needed to raise an 10 kg object 2 m off the Earth’s surface? Would the work be the same on the Moon?

10. You run up a 10 m flight of stairs in 3 sec. Your mass is 60 kg. How much Potential Energy did you gain? How much work did you do? What was your Power?

11. A steel tape (a = 1.300 E -5) measures 150.0 m at 10 degrees C. Its length at 22.00 degrees C is?

12. A block of copper with mass 0.500 kg is heated to 300. degrees Celsius from 210. degrees Celsius. The specific heat capacity of copper is 387 J/ (kg*C). The heat absorbed by the copper block is?

13. 0.5000 kg of water at 30.00 degrees Celsius is cooled, with the removal of 6.300 E4 J of heat. What is the final temperature of the water? Specific heat capacity of water is 4186 kJ/kg C

14. A force of 3.00 N is applied to a spring whose elastic constant is 0.20 N/cm. Its change in length is?

Answer 1

Can you do at least two questions at a time?

1.  Q1=Q2

Q1 = m1Cp1 ( T2-T1) (heat absorbed by water)

Q2 = m2Cp2 ( T3-T2) (heat liberated by aluminum)

m1= 0.5 kg

m2= 0.4 kg

Cp1 = 4186 kJ/kg*C

Cp2= 900 kJ/kg*C

T3= 100 *C

T2= ?

T1= 20*C

We have to find T2

Q1 = Q2 and

m1Cp1 ( T2-T1) = m2Cp2 ( T3-T2)

T2 = [m2Cp2T3 + m1Cp1T1] /[m1Cp1 + m2Cp2]

Now just compute Q1 = m1Cp1 ( T2-T1) (heat absorbed by water)

2. Study the figure and "Be able to read a phase diagram ...."

3.  I though it was self evident. What happens when we heat something? Do we add energy to it?

4. Earlier we have used

Q = mCp ( T2-T1)

Cp= Q/[m(T2-T1)]

I hope it helps.

Now go and finish your homework.