1. Review Chapter 10 Work 1.The type of energy that is the energy stored, energy of position or the energy of a situation is called: ans: potential energy 2. Energy of the moving particles that make up matter is called: ans: thermal energy 3. Energy of changing matter is a process of fusion or fission is called ans nuclear energy 4. The ability to cause change or do work is called: ans: work 5. Energy of motion is called___________ and is defined mathematically __________? ans: kinetic energy and KE = ½ mv 2

2. 6. How will the kinetic energy of matter be affected if the velocity of a constant mass is halved? ans: kinetic energy is decrease 4x or ¼ th original amount 7. With a constant kinetic energy, if the mass of an object is doubled, how is the velocity of its motion affected? ans: velocity is decreased by a factor of 2x 8. What will happen to the potential energy of a 2 kg mass that is moved from the 2 m above the floor to 4 m above the floor? ans: PE will increase by a factor of 2x 9. Which object has a greater kinetic energy: 2 kg mass at 2 m/s or 0.25 kg mass at 6 m/s ans: 0.25 kg at 6 m/s

3. 10. The total energy of a system is equal to the _____ plus the _____ ? ans: Mechanical energy = kinetic energy + potential energy 11. How much energy is needed to move a 5 kg mass from 1 m to 3 m above the floor? ans: PE 3m – PE 1m = change in the PE; 147 J - 49 J = 98 J 12. A book bag weighs 30 N. If the bag is lifted 1.5 m, how much work is done? ans: Fw = 30 N and W = Fd, Work is 45 J 13. The amount of force needed to move a 1 kg mass one meter in one second is called: ans: Watt

4. 14. The total amount of work of a system is conserved. Therefore any Work done in that system has a cooresponding change in the ______ ans: kinetic energy 15. What concept in this unit describes the idea in #14 above? ans: Work-Kinetic Energy Theorem 16. If the total amount of energy to throw a ball 4 m into the air is 89 J. What is the total amount of energy of the ball when it travels back down to its origin? NO resistance. ans: the same amount, 89 J 17. A rock is set 20 m above the ground giving it a potential energy of 250 J. What is the kinetic energy of the rock just before it hits the ground? ans: KE = PE, the same amount 250 J

5. 18.True or False: No work is done if the mass does not move? ans: true 19.What is the force applied to move a 5 kg mass 20 m at a velocity of 5 m/s? ans: Fd = ½ mv 2 ; F = 3.125 N 20.If a 120 kg mass has a KE = 2500 J, what is the speed of the mass? ans: Fd = ½ mv 2 ; v = 6.5 m/s 21.What is the mechanical energy of a system if the KE = 32 J and the PE = 15 J ? ans: ME = PE + KE ; ME = 15 J + 32 J = 47 J

6. 22.The loss in energy when a rubber ball bounces is transferred to: ans: thermal energy 23. The unbalanced forces in a pendulum that causes the pendulum to come to a stop is called: ans: thermal energy 23.How hot or cold something is describes: ans: temperature 24.A spring has a spring constant of 23 N/m. When a 0.5 kg mass is hung from the spring it hangs changes from 2 cm to 9 cm. What is the elastic potential? ans: PE ele = ½ kx 2 ; PE ele = 563.5 J

7. 25.True or False: A force of 25 N applied for 3 m in 4.5 s has more power than 75 J of work done in 2.5 s ? ans: (25N x 2.5m)/4.5s = 13.9 W v. 75J / 2.5s = 30 W FALSE 26. If it takes 532.7 N of force to push a Nissan Leaf that has a mass of 554 kg from rest to 15 m/s in 7.8s, what is the power required? ans: W = ½ mv2 give W = 62325 J P = W/t ; P 62325/7.8s =7990.4 W or ans: P = Fv ; P = 532.7 N x 15 m/s = 7990.5 W 27.Complete the alpha decay: 96Cm247  ans: 96 Cm 247  94 Pu 243 + 2 He 4

8. 28.Complete the following decay: ___________  54 Xe 131 + o e 1- ans: 53 I 131 29. What type of radioactive decay is shown in #28 above? ans: beta b/c there is no change in mass 30. What is the half life of a 100 g sample of N-16 that decays to 12.5 g of N-16 in 21.6 s? ans: find ‘n’ ; n = 100/2 = 50/2 = 25/2 = 12.5, n=3 then find t 1/2 ; n = t/t 1/2 so t 1/2 = t/n = 7.2s 31. C-14 has a half life of 5730 yrs. How much of a 144 g sample of C-14 remains after 1719 yrs? ans: A = A o /2 = 18 gA = A o (.5) t/h = 18.1 g