Some Mechanical Properties of Matter Physics - Some Mechanical Properties of Matter

If water in one flask and castor oil in other are violently shaken and kept on a table, which will come to rest earlier?

The contact angle between water and glass is 0^º. When water is poured in a glass to the maximum of its capacity, the water surface is convex upward. The angle of contact in such a situation is more than 90^º. Explain.

A uniform vertical tube of circular cross-section contains a liquid. The contact angle is 90^º. Consider a diameter of the tube lying in the surface of the liquid. The surface to the right of this diameter pulls the surface on the left of it. What keeps the surface on the left in equilibrium?

In the upper wire is made of steel and the lower of copper. The wires have equal cross-section. Find the ratio of the longitudinal strains developed in the two wires.

The force of surface tension acts tangentially to the surface whereas the force due to air pressure acts perpendicularly on the surface. How is then the force due to excess pressure inside a bubble balanced by the force due to the surface tension?

The two wires shown in are made of the,

same material which has a breaking stress of 8 × 10⁸N/m². The area of cross-section of the upper wire is 0.006cm² and that of the lower wire is 0.003cm². The mass m₁ = 10kg, m₂ = 20kg and the hanger is light:

1. Find the maximum load that can be put on the hanger without breaking a wire. Which wire will break first if the load is increased?
2. Repeat the above part if m₁ = 10kg and m₂ = 36kg.

Estimate the change in the density of water in ocean at a depth of 400m below the surface. The density of water at the surface = 1030kg/m³ and the bulk modulus of water = 2 × 10⁹N/m².

A steel wire of original length 1m and cross-sectional area 4.00mm² is clamped at the two ends so that it lies horizontally and without tension. If a load of 2.16kg is suspended from the middle point of the wire, what would be its vertical depression? Y of the steel = 2.0 × 10¹¹N/m² Take g = 10m/s².

A capillary tube of radius 0.50mm is dipped vertically in a pot of water. Find the difference between the pressure of the water in the tube 5.0cm below the surface and the atmospheric pressure. Surface tension of water = 0.075N/m.

A vertical metal cylinder of radius 2cm and length 2m is fixed at the lower end and a load of 100kg is put on it. Find

1. The stress.
2. The strain and.
3. The compression of the cylinder. Young's modulus of the metal = 2 × 10¹¹ N/m².

A steel plate of face area 4cm² and thickness 0.5cm is fixed rigidly at the lower surface. A tangential force of 10N is applied on the upper surface. Find the lateral displacement of the upper surface with respect to the lower surface. Rigidity modulus of steel = 8.4 × 10¹⁰N/m².

A 5.0cm long straight piece of thread is kept on the surface of water. Find the force with which the surface on one side of the thread pulls it. Surface tension of water = 0.076N/m.

A steel blade placed gently on the surface of water floats on it. If the same blade is kept well inside the water, it sinks. Explain.

When a glass capillary tube is dipped at one end in water, water rises in the tube. The gravitational potential energy is thus increased. Is it a violation of conservation of energy?

If a mosquito is dipped into water and released, it is not able to fly till it is dry again. Explain.

When some wax is rubbed on a cloth, it becomes waterproof. Explain.

The excess pressure inside a soap bubble is twice the excess pressure inside a second soap bubble. The volume of the first bubble is n times the volume of the second where n is:

1. 4
2. 2
3. 1
4. 0.125.

When a metal wire elongates by hanging a load on it, the gravitational potential energy is decreased.

1. This energy completely appears as the increased kinetic energy of the block.
2. This energy completely appears as the increased elastic potential energy of the wire.
3. This energy completely appears as heat.
4. None of these.

A heave uniform rod Is hanging vertically form a foxed support. It is stretched by its won weight. The diameter of the rod is.

1. Smallest at the top and gradually increases down the rod.
2. Largest at the top and gradually decreased down the rod.
3. Uniform everywhere.
4. Maximum in the middle.

The breaking stress of a wire depends on:

1. Material of the wire.
2. Length of the wire.
3. Radius of the wire.
4. Shape of the cross-section.