Question

2. The iron sights on a rifle are adjusted for elevation based on the amount the bullet will drop with distance. A rifle fires a 8 gram 7.62x39 bullet from a horizontal bench. The bench rest is elevated 1,4 from the ground. The bullet is observed to strike the ground at a distance of 1.2 km from the firing location. What was the muzzle velocity of the bullet? b. At what angle does the bullet hit the ground? c. If the gun barrel is.8 m long and the explosive force of the gun powder on the bullet is constant over the length of the barrel, what is the average force the gun powder exerts on the bullet while it is in the barrel? d. (extra) If the radius of the earth is 6353 km, how fast would the bullet have to travel to never hit the ground?

Answer 1

Date DELTA PONO. SOLUTION Tusind " au caso Tintem 1.2 km Horizontal Range R = usinzo Here usine - 1200m. To maximum Height He usino = 14om So u = 2g x 140 to Sino put this in ean 29X1400 Sin20 =1260 Sinoxg 2810 em X 2 Sino90 - 1210 sino 560 Coto= 1200 Coto = 1200 = 12 T = 120 tono sta 4a67 Octaw (4.67) = 77.8° (6) a

Date DELTA PO NO a putting vanego in equ @ w = 28X1400 Sim20 42 = 2x9.841400 S777-8 u²=28085.97 u=167.59 m/s. 27440 0.977 (c) principle of Conservation of momente momentum before firing - Total moments after firing o=anut mu my=-me an is massg bullet MV= 8 x16 5167.59 m=8m = 8x10 kg Vivelang bullet MW= 1.34 0 - =767-54 mps Mow gan barrik is 0.8m long to the gun relort and travel distence - 0.8m with recoil velocity V. using equatic v² - utras 1² otas v² = 2a xois - 16a V- 1.26 Ja Mu=1.34 mx1.2680 = 1.34 mja = 134 1.06 1.26

Date DELTA PO NO Misaatio ma=112 ma=1.12 mis mess of gun. d) R=usin 20 Rwill be maximun 20=4 or our - Rmox = 7 R is the Radiusg earth R = 6353 km - 6753x10 m. uz Rg=6353X10²x9.8 42 6225.9 810² h = 7890046 m/s