An aluminum rod is 10.0 cm long and a steel rod is 80.0 cm long when both rods are at a temperature of 15°C. Both rods have the same diameter. The rods are now joined end-to-end to form a rod 90.0 cm long. If the temperature is now raised from 15°C to 90°C, what is the increase in the length of the joined rod? The coefficient of linear expansion of aluminum is 2.4 × 10-5 K-1 and that of steel is 1.2 × 10-5 K-1.

We have that for the Question, it can be said that

the increase in the length of the joined rod

From the question we are told

An aluminum rod is 10.0 cm long and a steel rod is 80.0 cm long when both rods are at a temperature of 15°C. Both rods have the same diameter.

The rods are now joined end-to-end to form a rod 90.0 cm long.

If the temperature is now raised from 15°C to 90°C,

what is the increase in the length of the joined rod?

The coefficient of linear expansion of aluminum is 2.4 × 10-5 K-1 and that of steel is 1.2 × 10-5 K-1.

Generally the equation for the change length  is mathematically given as

Hence

the increase in the length of the joined rod

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0.9 cm

Explanation:

The computation in the increase in the length of the joined rod is shown below:

As we know that

Increase in length = increase in the length of aluminum rod + increase in The length of steel rod

= 0.9 cm

We simply added the length of aluminium rod and length of steel rod so that the length of the joined rod could come and the same is to be considered  

b) 10 minutes

girls stopped for 10 minutes.