In the figure below, a 3.30 g bullet is fired horizontally at two blocks at rest
ID: 2263807 • Letter: I
Question
In the figure below, a 3.30 g bullet is fired horizontally at two blocks at rest on a frictionless tabletop. The bullet passes through the first block, with mass 1.20 kg, and embeds itself in the second, with mass 1.80 kg. Speeds of 0.630 m/s and 1.40 m/s, respectively, are thereby given to the blocks. (Note: You may neglect the mass removed from the first block by the bullet.)
(a) Find the speed of the bullet immediately after it emerges from the first block.
765.0m/s
(b) Find the bullet's original speed.
992.73
(c) How much mechanical energy was dispelled into the environment during the bullet's collision with the first block?
______
(d) How much mechanical energy was dispelled into the environment during the bullet's collision with the second block?
______
Explanation / Answer
a) on second block , momentum conservation,
0.0033v = (1.80 + 0.0033) x 1.40
v = 765.04 m/s
b) on block 1 ,
0.0033u = 0.0033 x 765.04 + 1.20 x 0.630
u = 992.73 m/s
c) energy = 0.0033 x 992.73^2 /2 - [ 0.003 x 765.04^2/2 + 1.20 x 0.63^2 /2 ]
= 660.13J
d) energy = [ 0.003 x 765.04^2/2 ] - [ (0.0033 +1.80) x 1.40^2 /2]
= 963.95 J