The dimensions of an open box are 50 cm, 40 cm and 23 cm. Its thickness is 2 cm. If 1 cubic cm of metal used in the box weighs 0.5 gms, find the weight of the box.
Outer dimensions of the box = 50 cm, 40 cm and 23 cm
Outer volume of the box = 50 × 40 × 23 = 46000 cu cm
Inner dimensions of the box:
Length = (50 – 2×3) = 44 cm
Breadth = (40 – 2×3) = 34 cm
Height = (23 – 30 = 20 cm
Inner volume of the box = 44 × 34 × 20 = 29920 cu cm
Volume of the wood = Outer Volume – Inner Volume = 46000 – 29920 = 16080 cu cm
Weight of the wood per cu cm = 0.5 g
Weight of the wood used for making the box = 16080 × 0.5 = 8040 g = 8.04 kg.
Workspace
A hollow iron pipe is 21 cm long and its external diameter is 8 cm. If the thickness of the pipe is 1 cm and iron weighs 8 g/cm3, then the weight of the pipe is:
Volume will be length * breadth * height, but in this case two heights are given so we will take average,
Workspace
Find the number of bricks, each measuring 24 cm x 12 cm x 8 cm, required to construct a wall 24 m long, 8m high and 60 cm thick, if 10% of the wall is filled with mortar?
Number of bricks = [(90/100) x (2400 x 800 x 60) ]/ (24 x 12 x 8) = 45000
Workspace
A large cube is formed from the material obtained by melting three smaller cubes of 3, 4 and 5 cm side. What is the ratio of the total surface areas of the smaller cubes and the large cube?
A metallic sheet is of rectangular shape with dimensions 48 m x 36 m. From each of its corners, a square is cut off so as to make an open box. If the length of the square is 8 m, the volume of the box (in m3) is:
The cost of the paint is Rs. 36.50 per kg. If 1 kg of paint covers 16 square feet, how much will it cost to paint outside of a cube having 8 feet each side?
Volume of the box = (32 x 20 x 8) m3 = 5120 m3.
