Impulse and Momentum

Transcription

1 Impule and Momentum 1. A ca poee 20,000 unit of momentum. What would be the ca' new momentum if... A. it elocity wee doubled. B. it elocity wee tipled. C. it ma wee doubled (by adding moe paenge and a geate load) D. both it elocity wee doubled and it ma wee doubled. 2. A halfback (m = 60 kg), a tight end (m = 90 kg), and a lineman (m = 120 kg) ae unning down the football field. Conide thei motion map below. Remembe each dot epeent 1 econd. Note the ditance taeled by each playe in one econd. Compae the elocitie of thee thee playe. How many time geate i the elocity of the halfback and the elocity of the tight end than the elocity of the lineman? If the lineman i moing at 3m/ then what ae the elocitie of the tight end and halfback? Which playe ha the geatet momentum? Explain. 3. A 0.50-kg cat (#1) i pulled with a 1.0-N foce fo 1 econd; anothe 0.50 kg cat (#2) i pulled with a N- foce fo 0.50 econd. a. Which cat (#1 o #2) ha the geatet impule? Explain. b. Which cat (#1 o #2) ha the geatet change in momentum? Explain. 4. The diagam to the ight depict the befoe- and afte-colliion peed of a ca which undegoe a head-oncolliion with a wall. In Cae A, the ca bounce off the wall eulting in a negatie elocity. In Cae B, the ca "tick" to the wall. (the ma of both ca i the ame) a. In which cae (A o B) i the change in elocity the geatet? Explain. b. In which cae (A o B) i the change in momentum the geatet? Explain. c. In which cae (A o B) i the impule the geatet auming they ae both in contact with the wall fo the ame amount of time? Explain. d. In which cae (A o B) i the foce which act upon the ca the geatet (aume contact time ae the ame in both cae)? Explain.

2 5. Rhonda, who ha a ma of 60.0 kg, i iding at 25.0 m/ in he pot ca when he mut uddenly lam on the bake to aoid hitting a dog coing the oad. She tike the ai bag, which bing he body to a top in What aeage foce doe the eat belt exet on he? 6. If Rhonda, in poblem 6, had not been weaing he eat belt and not had an ai bag, then the windhield would hae topped he head in What aeage foce would the windhield hae exeted on he? 7. A hockey playe applie an aeage foce of 80.0 N to a 0.25 kg hockey puck fo a time of 0.10 econd. Detemine the impule expeienced by the hockey puck. 8. If a 5-kg object expeience a 10-N foce fo a duation of 0.1-econd, then what i the momentum change of the object? 9. Rank the object (A E) in ode of inceaing momentum. ma = 30 g mb = 40 g mc = 300 g md = 10 g me = 20 g = 3 m/ 5 / B = m A C = 2 m/ D = 5 m/ E = 7 m/ Leat Geatet 10. The Poition. Time gaph i hown fo an object of ma 0.60 kg. Daw the coeponding Momentum. Time gaph. (Ue an appopiate numeical cale fo you Momentum. Time gaph). xm ( ) pkg ( m/ )

3 11. The Momentum. Time gaph i hown fo an object of ma 500 g. Daw the coeponding Acceleation. Time gaph. (Ue an appopiate numeical cale fo you Acceleation. Time gaph) pkg ( m/ ) 2 am ( / ) 10 5 Below ae fou gaph of Foce. Time fo a 1.0 kg object that moe to the ight with a peed of 1.0 m/. What ae the elocitie (peed and diection) afte the impule?

4 16. Two cat ae placed on a low fiction tack. One cat ha a ma of m 1 = 0.50 kg and the othe ha a ma of m 2 = 50 kg. Both cat, initially at et, ae ubject to the ame foce F fo a peiod of 1.0. In the end, once the foce i emoed, which cat ha the geate momentum? Explain. 17. Two cat ae placed on a low fiction tack. One cat ha a ma of m 1 = 0.30 kg and the othe ha a ma of m 2 = 30 kg. Both cat, initially at et, ae ubject to the ame foce F fo a ditance of 1.0 m. In the end, once the foce i emoed, which cat ha the geate momentum? Explain. (Hint: Which one i puhed fo a longe time?) Quetion efe to Figue 1 below which depict a pendulum that wing down fom ome height and collide with an aluminum pot (the pendulum bob i moing hoizontally when it tike the pot). The pot i not ecued to anything and i fee to fall if hit had enough by the pendulum. The point i to knock the pot oe, o you e gien a choice of two type of mateial fo you pendulum; one i a bouncy ubbe ball, and the othe i a wad of ticky clay. Both hae the ame ma m, and you may aume that both hit the pot with the ame peed (we will coe thi point once we get to enegy). 18. Which will you chooe if you want to knock the pot oe? Why? Figue Both ball hit the pot with the ame initial momentum p ix but one bounce (the ubbe ball) with no lo of peed and the othe (the clay ball) tick. What ae the final momenta of each? Rubbe Ball: p fx, ubbe = Clay Ball: p fx, clay = 20. Now find the change in momentum fo each ball. Rubbe Ball: Δ p x, ubbe = Clay Ball: Δ p xclay, = 21. Which ball expeience the geate (in magnitude) impule? Explain. 22. Which law of phyic will tell u how the pot i affected? In othe wod, which ball exet a lage impule on the pot? 23. How doe thi affect you anwe to quetion #18? If you e changed you mind about the quetion, then tell why?

5 Refe to Figue 2 while anweing quetion Two ehicle, one mall (m) and one lage (M), moe towad each othe, collide, and bounce apat. m Figue Compae the foce that the mall ehicle exet on the lage ehicle F SL to the foce that the lage ehicle exet on the mall F. Ae the foce equal o i one lage than the othe? Explain. LS 25. Compae the time inteal oe which thee foce act. Ae the time inteal equal o i one lage than the othe? Explain. 26. Now compae the impule that i gien to the lage ehicle to that which i gien to the mall ehicle. Explain. 27. Sketch a gaph of Foce. Time fo each ehicle. Do thee gaph agee with you anwe to quetion #26? (Hint: Remembe Newton thid law.) M FSL( N) FLS ( N) 28. Compae the change in elocity of the mall ehicle to the change in elocity of the lage ehicle. 29. What i the total change in momentum fo the entie ytem (both lage and mall ehicle)? I it negatie, poitie, o zeo? 30.You expeience an impule of 50 kg m/ fo a time of 1 econd when you ae puhed. You then expeience the ame impule fo a time of 5 econd. Which one would be mot comfotable fo you to expeience? (Hint: Compae the foce you would expeience in each ituation.) 31. You catch a wate balloon in a to o that the impule expeienced by the balloon i 4 kg m/. Should you apply a foce oe a long peiod of time o a hot peiod of time to peent the balloon fom beaking?