Calculating Temperature Change of Steel Strut in Submarine

[BunDa4Th]

Homework Statement

Suppose a steel strut with cross-sectional area 7.00x10^-4 m2 and length 2.50 m is bolted between two rigid bulkheads in the engine room of a submarine.
(a) Calculate the change in temperature of the strut if it absorbs an energy of 3.00x10^5 J. °C

Homework Equations

Q = mcDeltaT
DeltaT = Q/mc

The Attempt at a Solution

I tried using the formula DeltaT = Q/mc

Delta T = 3.00 x 10^5/ m(448 J/kg *C)

the problem I am having is how do i find the mass?

 

[andrevdh]

Density of steel $$\rho _{steel} = 7.8 \times 10^3\ kg/m^3$$

 

[BunDa4Th]

I still don't understand how to solve this problem knowing the density of steel.

 

[Doc Al]

Use it to find the mass of the steel.

 

[BunDa4Th]

m = psteelV

how do i find v?

 

[cristo]

No. You are given the cross sectional area and the length. Do you know how to calculate the volume from this information?

 

[BunDa4Th]

okay i figure out how to solve this.

it was P_steel x cross sec. area / length = m

 

[cristo]

Not quite: V=A*l (where A is the cross sec. area, l is the length). Above you had the correct formula: m= ρ*V and so m= ρ*A*l

 

[BunDa4Th]

oops, my mistake. yes i did mean m = p x A x l that was how i got the correct answer.

Thanks for the correction and help.