Kev sib npaug ntawm kev xav

3 cov lus nug txog kev sib npaug ntawm Impulse

1. Ib lub tsheb uas hnyav 250 kg tab tom khiav nrog qhov ceev ntawm 72 km/teev, ces nrawm nrog lub zog tas li kom hauv 5 vib nas this nws qhov ceev dhau los ua 80 km/teev. Txheeb xyuas lub zog rau 5 vib nas this.

Paub:

Qhov hnyav ntawm lub tsheb (m) = 250 kg

Qhov ceev pib (v_o) = 72 km/teev = 20 m/s

Qhov ceev kawg (v_t) = 80 km/teev = 22 m/s

Lub sijhawm luv (t) = 5 vib nas this

SE pob: Txheeb xyuas qhov impulse (I)

tshuaj:

Cov qauv mis ntawm Impulse: Impulse = Kev hloov pauv ntawm momentum

Kuv = Δp

Kuv = m (v)_t -v_o) = (250)(22 – 20) = (250)(2)

Kuv = 500 kg m/s

2. Ib yam khoom uas hnyav 0.4 kg thaum xub thawj txav nrog qhov ceev ntawm 20 m/s raug nres los ntawm lub zog tas li ntawm 50 N hauv ib lub sijhawm. Lub zog txav loj npaum li cas?

Paub Tias:

Qhov hnyav (m) = 0.4 kg

Qhov ceev (v)_o) = 20 m/s

Qhov ceev kawg (v_t) = 0 m/s

Lub zog (F) = 50 N

SE pob: Impulse (Kuv)

tshuaj:

Cov qauv mis ntawm Impulse: Impulse = Kev hloov pauv ntawm momentum

Kuv = Δp

Kuv = m (v)_t -v_o) = (0,4)(0 – 20) = (0,4)(-20)

Kuv = 8 kg m/s

3. Ib yam khoom uas muaj qhov hnyav m txav mus rau qhov ceev v tas li, yog li ntawd lub zog ntawm yam khoom yog ...

tshuaj

Impulse = kev hloov pauv ntawm momentum. Momentum hloov thaum qhov hnyav lossis qhov ceev hloov pauv. Yog li ntawd, yog tias qhov ceev thiab qhov hnyav tas li ces tsis muaj kev hloov pauv ntawm momentum. Yog li ntawd tsis muaj impulses.