A rigid bar of mass 15 kg is supported symmetrically by three wires each 2.0 m long. Those at each end are of copper and the middle one is of iron. Determine the ratio of their diameters if each is to have the same tension.

A uniform rope of length 12 m amd mass 6 kg hangs vertically from a rigid support.A block of mass 2 kg is attached to the free end of the rope.A transverse pulse of wave length 0.06m is produced at the lower end of the rope.What is the wavelength of the pulse when it reaches the top of the rope?

Two objects, each of mass 1.5 kg, are moving in the same straight line but in opposite directions. The velocity of each object is 2.5 m s^-1 before the collision during which they stick together. What will be the velocity of the combined object after collision?

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

Two billiard balls each of mass 0.05 kg moving in opposite directions with speed 6 m s~1 collide and rebound with the same speed. What is the impulse imparted to each ball due to the other?

Two persons manage to push a motorcar of mass 1200 kg at a uniform velocity along a level road, the same motorcar can be pushed by three persons to produce an acceleration of 0.2 m s^-2 . With what force does each person push the motorcar? (Assume that all persons push the motorcar with the same muscular effort.)

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?

Two bodies of masses 10 kg and 20 kg respectively kept on a smooth, horizontal surface are tied to the ends of a light string. A horizontal force F = 600 N is applied to (i) A, (ii) B along the direction of string. What is the tension in the string in each case?

In one fortnight of a given month,there was a rainfall of 10 cm in a river valley.If the area of the vally is 7280km^2 ,show that the total rainfall was approximately equivalent to the addition to the normal water of three rivers each 1072 km long.75m wide and 3m deep.

Let us assume that our galaxy consists of 2.5 xx 10^11 stars each of one solar mass. How long will a star at a distance of 50,000 ly from the galactic centre take to complete one revolution? Take the diameter of the Milky Way to be 10^5 ly.