First slide

Thermal expansion

Question

A block is hanged by means of two identical wires having cross section area 1mm² as shown. If the temperature is lowered by ΔT = 10°C, find the mass to be added to hanging mass such that the junction remains at its initial position
(α = 2×10^-5/°C, Y = 5 × 10¹¹Pa, g = 10m/s²)

Difficult

A

4 kg
B

8 kg
C

12 kg
D

16 kg

Solution

Resolving tension into components T sinθ components cancel each other
Thermal force $T = YA\alpha \Delta t$
$2T\cos \theta = mg; 2(YA\alpha \Delta t)\cos {53^o} = m{ \times }10$
$2 \times 5 \times {10^{11}} \times {10^{ - 6}} \times 2 \times {10^{ - 5}} \times 10 \times \frac{3}{5} = m(10)$
m = 12 kg

Get Instant Solutions

When in doubt download our app. Now available Google Play Store- Doubts App

Recieve an sms with download link

Doubts App

OR

SCAN ME

Doubts App

Doubts App