A car has two wipes which do not overlap.Each wiper has a blade of length 25 cm seeping through an angle of `115^@`.Find the total area cleaned at each sweep of the blades.

An umbrella has 8 ribs which are equally spaced (see Fig.12.13). Assuming unbrella to be a flat circle of radius 45 cm.Find the area between the two consecutive ribs of the umbrella.

Rachel,an engineering student,was asked to make a model shaped like a cyclinder with two cones attached at its two ends by using a thin aluminium sheet.The diameter of the model is 3 cm and its length is 12cm.If each cone has a height of 2 cm,find the volume of air contained in the model that Rachel made.(Assume the outer and inner dimensions of the model to be nearly the same).

Diagram of the adjacent picture frame has outer dimensions =24cm xx 28 and inner dimensions 16cm xx 20 . Find the area of each section of the frame, if the width of each section is same.

The floor of a building consists of 3000 tiles which are rhombus shaped and each of its diagonals are 45cm and 30cm in length. Find the total cost of polishing the floor, if the cost per m^2 is Rs. 4.

In Fig.12.25,ABCD is a square of side 14 cm.with centres A,B,C and D,four circles are drawn such that each circle touch externally two of the remaining three circles.Find the area of the shaded region.

The length of a radius of a circle is 10 cm.A chord substends an angle 90^@ at the centre.Find the area of each of the two segments made by the chord. [sin90^@=1]

A plane is in level flight at constant speed and each of its two wings has an area of 25 m^2 . If the speed of the air is 180 km/h over the lower wing and 234 km/h over the upper wing surface, determine the plane’s mass. (Take air density to be 1 kg m^-3) .

The cylindrical tube of a spray pump has a cross-section of 8.0 cm2 one end of which has 40 fine holes each of diameter 1.0 mm. If the liquid flow inside the tube is 1.5 m min-^1 , what is the speed of ejection of the liquid through the holes?