Experien 3 NEWTON S LAWS O OTION Purpose: Invesigaion of Newon s Laws of oion using air rack rail. Equipens: Air rack, blower (air source), ier, phoogaes, s wih differen asses, asses (0g), rope, pencil, eraser, scienific calculaor. Inroducion Newon s Laws of oions: I ) Newon s irs Law of oion: Law of Ineria If an objec does no inerac wih oher objecs, i is possible o idenify a reference frae in which he objec has zero acceleraion. The resisance of he change of he velociy is called ineria. The firs law of Newon is; If he ne force acing on an objec is equal o zero (balanced force), he objec ends o keep is posiion. If he objecs is in res, i coninues in a sae of res, if i is oving, i coninues o ove wihou urning or changing is speed. II ) Second Law: Law of oion When a force acs on an objec, he velociy of he objec changes, he rae of change of velociy is equal o acceleraion, so he objec gains an acceleraion. Second law correlaes an kineaic quaniy acceleraion o a dynaic quaniiy of force. Iagine perforing an experien in which you push a block of fixed ass across a fricionless horizonal surface. When you exer soe horizonal force on he block, i oves wih soe acceleraion. The acceleraion of an objec is direcly proporional o he force acing on i. he raio of he force and he acceleraion is always consan and i is called, ass.... cons an a a () We can express he second law as: an objec under a consan force gains a consan acceleraion. a () This is he fundaenal equaion of dynaics. The equaion defines he force. orce is he quaniiy ha changes he oveen of an objec. I is an vecor and has he sae direcion wih acceleraion. The uni of he force in SI uni syse is Newon (N). N is he force ha gives /s acceleraion o an objec wih kg ass. The uni of force in CGS uni syse is Dyn.
Newon s secon law coprises he firs law. If he ne force acing on an objec is equal o zero hen he acceleraion becoes zero depending on he fundaenal equaion and his eans he velociy of he objec does no change, i says consan. III ) Third Law: Acion-Reacion Law orce rises fro he ineracion of he objecs and due o his reason i always exiss in pairs. To every acion here is always an equal and opposie reacion: or he forces of wo bodies on each oher are always equal and are direced in opposie direcions. If ve forces. ' forces are he ones ha he objecs ac on each oher hen,. These forces are called as acion-reacion The raio of he forces ha he objecs are applying on each oher can be provided wih oenu-ipulse relaion. oeu is he produc of he ass and he velociy of an objec, in oher words i is he aoun of oveen. p v (3) The direcion of he oenu is sae wih he direcion of he velociy. The produc of he force and is acing ie is called ipulse. If a force,, is applied on an objec for a ie d, hen he ipulse is d. Subsiuion of equaion (3) in equaion () gives us, d( v) dp d d I can be seen ha, he ne force ha causes acceleraion is he he of change of he oenu of a paricle. According o equaion (4), he ipuls applied ill he objecs seperae are, p ve p (5) So using equaion (), he raio of he forces on he objecs is, l l (6) (4)
. Experien. Place he phoogaes as shown in igure- adjus he air rack rail syse parallel o he ground wih he help of he leg screws. igure I ) Applicaion of Newon s s Law:. ix he rubber reflecor o he lef end of he rail and rese he iers. Push he slowly so i can reach he reflecor and reurn. Read he ransiion ie of he (, ) ha reurned fro he reflecor and wrie he down in Table-. 3. easure he lengh of he ( ) and calculae he velociies passing under he phoogaes using equaion (7), and wrie down in Table- and copare he o each oher. Repea he experien wih differen s wih asses. v (7) Table (kg) () (s) (s) v (/s) v (/s) 4. Place he on he air rack syse as he says saionary and observe is oveen (if he objec is saionary, i does no change is posiion). 3
II ) Applicaion of Newon s nd Law: igure 5. Place he phoogaes wih a disance of s= 0,4 o each oher. ix a pulley o he end of he rail. The scale is conneced o he by a rope and hen hanged fro he pulley a he righ end of he rail. Afer he is locaed as shown in he figure, rese he iers and release he. 6. Read he ransiion ies of he passing fro wo phoogaes using he iers and wrie down in Table-. Add 0 gr asses o he scale and repea he easureens. 7. easure he lengh of he. 8. Calculae he velociies of he passsing fro he phoogaes using equaion (3), calculae he squares of he values and wrie down in Table-. a v v s (8) Calculae he acceleraion (a) of he ass using equaion (8) and wrie down in Table-. Table kefe (kg) (N) (s) (s) v (/s) v (/s) a (/s ) syse (kg) (kg) 0,03 0,04 0,05 0,06 average 9. ind he ass of he syse syse using equaion () which is equal o he su of he ass of he and he ass of he scale. Using he equaion of syse scale calculae 0. Calculae he average ass value of he and calculae he relaive error using equaion (9). average 4
real real real ave (9) III ) Applicaion of Newon s 3rd Law:. Place he rubber band reflecors on he s and pu he s on he rail as he rubber band reflecors becoe face o face beween he phoogaes as shown in igure 3 and rese he iers. Şekil 3. Copress he s wih equal forces and release he s a he sae ie. Read he ransiion ies of he s fro he iers (, ) and wrie down in Table-3. Table 3 (kg) (kg) (s) (s) 3. ind he raio of he forces acing on wo s using equaion (6). l... l 4. Repea he experien for differen asses and fill Table-3. 5
This page inenionally lef blank. 6