Question

Calculate the increase in energy of a brass bar of length 0.5m and cross sectional area 1,0cm2 when compressed with a load of 5kg weight along its length

Answer 1

Explanation:

Given : l=25cm=0.25m,A=0.8cm

2

=0.8×10

−4

m

2

,α=10

−5

/

o

C,Y=2×10

10

N,Δt=10

o

C .

The coefficient of thermal linear expansion is given by:

α=

l×Δt

Δl

l

Δl

=α×Δt

l

Δl

=10

−5

×10=10

−4

Now, Young's modulus of steel rod is given by:

Y=

A×Δl

F×l

whee F= force required to stretch the rod of cross section area A length l by Δl

F=

l

YAΔl

F=2×10

10

×0.8×10

−4

×10

−4

=160N