A 5.00-g bullet, traveling horizontally with a velocity of magnitude 300m/s, is
ID: 1385579 • Letter: A
Question
A 5.00-g bullet, traveling horizontally with a velocity of magnitude 300m/s, is fired into a wooden block with mass .800kg, initially at rest on a level surface. The bullet passes through the block and emerges with its speed reduced to 120m/s. the block slides a distance of 30.0 cm along the surface from its inital position.
(a) what is the coefficent of kinetic friction between block and surface?
(b) what is the decrease in the kinetic energy of the bullet?
answer= 189.5 J
(c) what is the kietic energy of the block at the instant after the bullet passes through it?
Explanation / Answer
answered this same question before....please go through it .feel free to ask in case of problem.
Q ) A 7.00 g bullet, traveling horizontally with a velocity of magnitude 450 m/s , is fired into a wooden block with mass of 0.850 kg , initially at rest on a level surface. The bullet passes through the block and emerges with its speed reduced to 190 m/s . The block slides a distance of 46.0 cm along the surface from its initial position.
a) What is the coefficient of kinetic friction between block and surface?
b) What is the decrease in kinetic energy of the bullet?
c) What is the kinetic energy of the block at the instant after the bullet passes through it?
ans )
The momentum imparted to the block is
0.007 kg (450 - 190) m/s = 1.82 kg m/s
Thus, the block should move at 1.82/0.850 = 2.14 m/s
The "normal" force on the block is its own weight, 8.33 N.
The deceleration due to friction is (v0)^2 / 2x = (2.14 m/s)^2 / (0.92 m) = 4.98 m/s^2
Thus the frictional force F = ma = (0.85 kg) (4.98 m/s^2) = 4.23 N
Coefficient of friction is F/N = 4.23/8.33 = 0.51
The bullet's kinetic energy was initially
(1/2) (0.007 kg) (450 m/s)^2
and later it was
(1/2) (0.007 kg) (190 m/s)^2
The difference is
(1/2) (0.007 kg) (202500 - 36100) m^2/s^2 =
(c) (1/2) (2.14 m/s)^2 (0.85 kg) =ans)
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.