Energy Practice 1 Key

Work, Energy, and Power Name: QA Energy Read from Lesson 1 of the Work, Energy and Power chapter at The Physics Classroom: http://www.physicsclassroom.com/CIass/energy/u511b.html http://www.physicscIassroom.com /Class/energy/ u511c.htmI http://www physicscIassroom com/CIass/energy/u511d htmI . . Work and Energy: sublevels 3 and 4 MOP Connection: 1. . Read each of the following statements and identify them as having to do with kinetic energy ( KE ), potential energy ( PE ) or both ( B). KE, PE or B? EE Statement: l . If an object is at rest, it certainly does NOT possess this form of ehergy . zm 2. Depends upon object mass and object height EE 3. The energy an object possesses due to its motion. B 4. The amount is expressed using the unit joule ( abbreviated J ). PE 5. The energy stored in an object due to its position (or height). 6. The amount depends upon the arbitrarily assigned zero level 7. Depends upon object mass and object speed. 8. If an object is at rest on the ground ( zero height), it certainly does! NOT possess this form of energy. I w _ 2. A toy car is moving along with 0.40 joules of kinetic energy. If its speed is doubled, then its new kinetic energy will be a. 0.10 J b. 0.20 J c. 0.80 J ^ . 0.40 J D possessing 0.80 joules of potential energy. Cd , e still 3. A young boy ’s glider is soaring through the air d, then the new potential energy will be speed is doubled and its heightj a. 0.20 J c. 1.60 ] } b. 0.40 J e. still 0.80 ] d . 3.20 ] 4. Which would ALWAYS be true of an object possessing a kinetic energy of 0 joules? C Om a . It is on the ground t. It is at resT} jzf It is moving on the ground £ It is moving. it is accelerating. f. It is at rest above ground \eve\ g. It is above the ground. It is moving above ground level. 5. If its - /5 ^ Which would ALWAYS be true of an object possessing a potential energy of 0 joules? 0 W\ c. It is moving on the ground ^ b. It is at rest. ( a. Tt is on the ground} ar it is moving. e. It is accelerating. f. It is at rest above ground level g. It is above the ground . h. It is moving above ground level. 6. Calculate the kinetic energy of a 5.2 kg object moving at 2.4 jp / s. PSYW J'v' V - 2- 7. Calculate the potential energy of a 5.2 kg object positioned 5.8 m above the ground . PSYW 8. Calculate speed of a 5.2 kg object that possesses 26.1 ] of kinetic energy. PSYW SLU . I J " ' TP l The Physics Classroom, 2009 - V~ - 3. 3 S Pagel Work, Energy, and Power 9. The total mechanical energy of an object is the b. PE minus the KE of the object a . KE minus the PE of the object c. the initial KE plus the initial PE of the.ohjprt _ ~ <^ d. KE plus the rb ot the object at any instant during its motion e. nna1 amount of KE and PE minus the initial amount of KE and PE ^ ^ . 10. If an object moves in such a manner as to conserve its total mechanical energy, then a. the amount of kinetic energy remains the same throughout its motion b. the amount of potential energy remains the same throughout its motion c. he amouyit-of .bo.th.the kinetic and the potential energv.»remams the.?ame thrpughout its motion d. the sum of the kinetic energy and the potential energy remains the same throughout Its mo^ _ - ^ 11. Determine the total mechanical energy (TME ) of the objects at positions A, B, C and D. Position A KE = 3000 J YE = 7000 J Position C 101, ObO “T A: Position D Position B KE = 5000} PE - 4D00 J KE = 40000} PE = 60000 J B: C; \ KE = 50000} PE = 30000 J 100 , 000 3 D: SP, ODD J 12. Calcula e the total mechanical energy (TME ) of a 5.2 kg object moving at 2.4 m / s and positioned 5.8 m above the ground . PSYW - ^ )( Ufj+ (pe -\“S j + 7 S/ 5 MB - k ( 5 J 13. Read the following descriptions and indicate whether the objects' KE, increases, decreases or remains the same ( = ). If it is impossible to tell, then answer ? 2?^ ^ a. A marble begins at an elevated position on top of an inclined ruler and rolls down to the tom of the ruler. ov > w w •• KE: PE: TME: • « t i t i i - KE: © * staircase w • m •> c. A cart is pulled from the bottom of arn incline to the top of the incline at a constant speed . w v » m m m m •« KE: » TM p * ^ ^ d. A physics KE: tiu Jud nt runs up a PE: •• at a constant speed. (T ) l © KE: rrt © m m m ^ m m m A pendulum bob is released from rest from an elevated position and swings to its lowest $f i = carskids t0 = g A KE: * TM E countertop. accurate itwfrom rest across^ level w 1 " t i rce is applied to a root beer mug to « w • •• PE: f. = w m m ©* 0i = W • PE: T W m m m TME: T i w u m m from a high speed to a stopping position along a level highway. «? ??? PE: TME: © The Physics Classroom, 2009 t l 0 t 0= Page 2