Test 3 phy 240. r r. You idiot! I meant transfer their genes

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Lambert King
7 years ago
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1 Tet 3 phy 40. a) Wite the definition of wok (pefoed on a paticle). b) Identify the wok in each veion of the wok-enegy theoe lited on the net page. c) Define ipule. d) Jutify each tep in the law of oentu conevation dp d dp i pi Fnet,i Fij 0 dt dt i i dt i i j i You idiot! I eant tanfe thei gene. A 50-kg kie tat fo et at the top (A) of an alot fictionle incline of height 0 a hown in the attached figue. At the botto of the incline (B), he encounte a hoizontal uface whee the coefficient of kinetic fiction between the ki and the now i 0.. Ignoing the effect of inteaction with the ai, deteine a) the gavitational wok pefoed on the kie (he cente of a) between the top (A) of the hill and the location whee he topped (C), b) the fictional wok along thi path, c) the ditance he taveled on the hoizontal uface befoe coing to et? 3. A -kg paticle ha a velocity of (i-3j) / and a 3.kg paticle ha a velocity of i /. Deteine a) the total oentu of the yte, b) the total kinetic enegy of the yte, c) the tanlational kinetic enegy of the yte 4. A foce F (/)y i + (/) j) i eeted on a paticle a it ove with contant velocity fo the oigin to point [,]. a) Mak the foce at the location indicated in the attached figue. b) Deteine the wok pefoed on the paticle by the ouce of the foce. c) I thee anothe foce eeted on the paticle? Jutify.

2 - - a) The wok dw done on a paticle diplaced along diffeential path d, by an object eeting foce F i defined a F dw d (We can define wok in an integal fo.) d F b) K The change in the kinetic enegy of a paticle i equal to the wok done by the net foce on the paticle. E The change in the echanical enegy of a paticle i equal to the wok done by all the foce not included in the potential enegy (nonconevative wok) K tanl. The change in the tanlational kinetic enegy of an object i equal to wok done by the net etenal foce on the cente of a of the object. c) If an object inteact with a paticle ove a cetain tie inteval (t,t ), the integal t I F( t)dt i called the ipule. d) definition of total oentu popety of the deivative of a function 3 ewton econd law fo a paticle (veion II) 4 definition of the net foce 5 ewton thid law and equieent of yte iolation t

3 - - a) Copaing the ize of the kie with the dienion of he path, one can liit the conideation to he K i 0J tanlational otion and appoiate W he body uing an appopiate h paticle at the cente of a of he body. ea the uface of eath the gavitational potential enegy of a paticle depend on it altitude above the efeence level U g Mgh Fo the definition of potential enegy U Mg h 50kg 9.8 W ( 0) 9.8kJ g g b) (Ecluding ai dag) thee ae only gavitational, noal, and (kinetic) fictional foce eeted on the body. Since along the entie path, the noal foce i alway pependicula to the diffeential diplaceent it wok ha a zeo value. The (tanlational) kinetic enegy of the kie i affected only by gavity and fiction. Fo the wok-enegy theoe the change in kinetic enegy of a paticle i equal to the net wok. Theefoe W f K g 0kJ 9.8kJ 9.8kJ c) Along the hoizontal pat of the path (whee the fictional foce wa eeted), the noal foce balance the gavitational foce. Hence it agnitude i equal to the weight of the kie. Fo the definition of the fiction coefficient, the agnitude of the fictional foce i elated to the agnitude of the noal foce. Theefoe the agnitude of the fictional foce i f k µ k µ kmg Uing the definition of wok, we can deteine the diplaceent. With a contant foce, integation of wok i ignificantly iplified. f dl co80 f d With the ealie eult (pat b) W W f f d f µ µ k f k path g Mg h µ Mg k K f 0J

4 - 3 - y kg v v v v 3 kg a) Fo the definition of the total oentu of a yte (and the definition of oentu of a paticle) P p v + v kg, 3 + 3kg,0 7, i kg [ ] [ ] [ ] i 6 b) Fo the definition of the total kinetic enegy of a yte (and the definition of the kinetic enegy of a paticle) K ([, 3] ) 4kg [,0] ( ) v kg i i tot Ki + i i c) Fo the definition of tanlational kinetic enegy and the elation of the velocity of cente of a to the total oentu K M kg ([ 7, 6] ) ( kg + 3kg ) Mv c P tanl. 8.5J 5J

5 - 4 - y F (,) [,] b) Diectly fo the definition of wok dw F d [ y, ] [ d,dy] yd + dy The paticle oved along a line along which y (and theefoe d dy). By diect ubtitution we obtain dw d + d 3 d Integating along the path path dw 0 3 d 3 0 6J c) Since the paticle ove with contant velocity the net foce eeted on the paticle ut be zeo (fo the wok-enegy theoe o fo ewton econd law), thee ut be at leat one foce which balance the given foce.

Mechanics 1: Motion in a Central Force Field

Mechanics 1: Motion in a Central Force Field Mechanics : Motion in a Cental Foce Field We now stud the popeties of a paticle of (constant) ass oving in a paticula tpe of foce field, a cental foce field. Cental foces ae ve ipotant in phsics and engineeing.