In figure (a) shows a thin liquid film supporting a small weight = `4.5 xx 10^-2` N. What is the weight supported by a film of the same liquid at the same temperature in Fig. (b) and (c)? Explain your answer physically.

A U-shaped wire is dipped in a soap solution, and removed. The thin soap film formed between the wire and the light slider supports a weight of 1.5 xx10^-2 N (which includes the small weight of the slider). The length of the slider is 30 cm. What is the surface tension of the film?

A steel tape 1m long is correctly calibrated for a temperature of 27.0 ^@C . The length of a steel rod measured by this tape is found to be 63.0 cm on a hot day when the temperature is 45.0 ^@C . What is the actual length of the steel rod on that day? What Is the length of the same steel rod on a day when the temperature is 27.0 ^@C ? Coefficient of linear expansion of steel = 1.20xx10^-5 K^-1 .

In figure. shows the distance-time graph of three objects A, B and C. Study the graph and answer the following question: (B) Are all three ever at the same point on the road?

Two inclined frictioniess tracks, one gradual and the other steep meet at A from where two stones are allowed to slide down from rest, one on each track (Fig. 6.16). Will the stones reach the bottom at the sam time? Will they reach there with the same speed? Explain. Given 0?t = 30°, 0_2 = 60°, and h = 10 m, what are the speeds and times taken by the two stones?

A large steel wheel is to be fitted on to a shaft of the same material. At 27 ^@C , the outer diameter of the shaft is 8.70 cm and the diameter of the central hole in the wheel is 8.69 cm. The shaft is cooled using ‘dry ice’. At what temperature of the shaft does the wheel slip on the shaft? Assume coefficient of linear expansion of the steel to be constant over the required temperature range: a_ steel = 1.20 xx 10^-5K^-1 .

A brass wire 1.8 m long at 27^@C is held taut with little tension between two rigid supports. If the wire is cooled to a temperature of 39 ^@C , what is the tension developed in the wire, if its. diameter is 2.0 mm? Co-efficient of linear expansion of brass = 2.0 XX 10^-5 K^-1 Young’s modulus of brass = 0.91xx10^11 P