Posted by **opp** on Thursday, April 26, 2012 at 1:12am.

A 10.9-g iron bullet with a speed of 4.00 102 m/s and a temperature of 20.0° C is stopped in a 0.400-kg block of wood, also at 20.0° C.

(a) At first all of the bullet's kinetic energy goes into the internal energy of the bullet. Calculate the temperature increase of the bullet. (b) After a short time the bullet and the block come to the same temperature T. Calculate T, assuming no heat is lost to the environment.

- phys -
**Elena**, Thursday, April 26, 2012 at 3:00pm
m1 = 10.9•10^-3 kg, v =400 m/s, t(o) = 20oC, m2 = 0.4 kg,.

specific heat of the iron and wood, respectively,

c1 = 444 J/kg, and c2 = 1700 J/kg.

(a) m1•v^2/2 = 10.9•10^-3•(400)^2/ 2 =872 J = QQ/

Q = m1•c1•Δt,

Δt = Q/ m1•c1 = 872/10.8•10^-3•444 = 180oC.

t(new) = 20oC + 180oC =200oC.

(b)

m1•c1•(200-t) = m2•c2•(t-20),

t = (m1•c1•200 + m2•c2•20)/( m1•c1+ m2•c2) =

(10.9•10^-3•444•200 + 0.4•1700•20)/(10.9•10^-3•444+0.4•1700) =

= 21.27oC

- phys -
**opp**, Saturday, April 28, 2012 at 5:12pm
thank you...what I originally did was use the wrong specific heat for iron.

## Answer This Question

## Related Questions

- Science - A lead bullet with a mass of 8.50 g traveling at 4.80 x 102 m/s ...
- physics - A 13 g bullet is stopped in a block of wood ( m w = 3 . 1 kg). The ...
- physics - A 12 g bullet is stopped in a block of wood (mw = 5.9 kg). The speed ...
- phycis - A 12 g bullet is stopped in a block of wood (mw = 5.9 kg). The speed of...
- Physics - A .22 rifle bullet, traveling at 373m/s, strikes a block of soft wood...
- p3 - A block of wood of mass 0.86 kg is initially at rest. A bullet of mass 0....
- physics - As shown in the diagram, a bullet of mass 7.0 g strikes a block of ...
- physics - A 20 g bullet moving horizontally with a speed v hits a 2-kg block of ...
- physics - A bullet of mass 10 g has a speed of 500 m/s. a) What is its kinetic ...
- Physics - A 6.6 g bullet is stopped in a block of wood (mw = 6 kg). The speed ...

More Related Questions