Question

Bullet B weighs 0.5 oz and blocks A and C both weigh 3 lb. The coefficient of friction between the blocks and the plane is PR = 0.39. Initially the bullet is moving at vo and blocks A and C are at rest (Figure 1). After the bullet passes through A, it becomes embedded in block C and all three objects come to stop in the positions shown (Figure 2). Determine the initial speed of the bullet vo- (Round the final answer to the nearest whole number.) B. e 6 in. 1 7 1 The initial speed of the bullet is ft's

Answer 1

Solutions Given: wt. of bulleta 0.502= 0.03125 pound 1 blocks = 3 lb. luka = 0.39 Deacceleastion due to Friction = = 0.39x386.0g in/s² 150.06 in (sec? ll & mg то) VA A 10a Fig. 1 Just After bullet passed block A Bbca 4in Fig. 2 Just After beflet embedded in block c Step 2: an fiG.2 and bullet V2 is combined speed of block a After impact. using formula 2 VFinal Vinitial +2 as W va - 2x(150.06 x 4 va 34.65 in/sec. using momentum conservation. (mot mc) V₂ =) Vi= 3.03125 X 34.65 0.03125 = 3360.85 in/sec.

block A so, speed of bullet after passing = 3360. g5 in/gec. Step 2 In fig. 1, VA is speed of after collision with bullet bullet after collision. using, final = Vinitial +298 VA - 2x (150:06x 6 [sa binch] VA = 42.43 in (sec IVA is speed of block A Just and Vi is speed of ~ using conservation ods Momentum movi+ MAVA I Vo is initial velocity of Bullet 0.03125 Vo = 0.03125X 3360.85 + 3x 42.43 Vo = 74.34.13 in/sec = 619.51 ft/sec! so, initial velocity of bollet is 619.51 ft/sec.