Physics 234-HW 9B A 12.0 gram bullet is traveling horizontally at 800 m\'s when
ID: 1775321 • Letter: P
Question
Physics 234-HW 9B A 12.0 gram bullet is traveling horizontally at 800 m's when it impacts and embeds itsellr in a 85.0 grams block of wood that is initially at rest. If the cocfficient of kinetic friction (js ) between the wood and the horizontal surface is 0.290 determine how far the combined masses will slide on the surface before coming to rest Physics 234-HW 9C A 4.20 kg mass (w) s an iniial velocity of l soi ms when it impacts and sicks to a 2.30 kg mass (m) initially traveling at -1.03 m/s. Assume there is no friction acting between the masses and the horizontal surface a) What is the final velocity of the combined masses after the collision? b) What percentage of the initial kinetic energy was "lost" over the collision interval?Explanation / Answer
(A) Applying momentum conservation,
(4.20 x 1.50) + (2.30 x - 1.03) = (4.20 + 2.30) v
v = 0.605 m/s ......Ans
(B) Ki = (4.20 x 1.50^2 / 2) + (2.30 x 1.03^2 / 2)
Ki = 5.945
Kf = (4.20 + 2.30) (0.605^2) /2 = 1.19 J
%lost = ( (Ki - Kf)/Ki) x 100 = 80 %