Solution: Density of wood = D = 0.6 gcm – 3 Determine (a) volume of the block (b) the volume of the block immersed when placed freely in a liquid of density 0.9 gcm – 3 ? (510 cm 3, 340 cm 3)

The density of aluminium is 2700 kgm – 3, the above calculated value of density is 2727 kgm – 3 nearest to the density of aluminium, so the material of the object is aluminium.ħ.10 A solid block of wood of density 0.6 gcm – 3 weighs 3.06 N in air.

Weight of object immersed in water = w 2 = 11.4 N Solution: weight of object in air = w 1 = 18 N Can you guess the material of the object? (2727 kgm – 3, Aluminium) Its weight is found to be 11.4 N when immersed in water. Volume of the cavity = 125 cm 3 – 120 cm 3 = 5 cm 3ħ.9 An object has weight 18 N in air. Volume of the whole cube = 5 cm x 5 cm x 5 cm = 125 cm 3 Solution: Length of the smallest side of the block = 7.5 cmĬalculations: (i) since the smallest edge of the block is rested on the horizontal surface. Find (i) The pressure exerted by the block on the surface (ii) Density of the wood. (2×10 5 Nm – 2)Īrea of head of a pin A = 10mm x 10mm = 10/10 cm x 10/10 cm =ħ.7 A uniform rectangular block of wood 20 cm x 7.5 cm x 7.5 cm and of mass 1000g stands on a horizontal surface with its longest edge vertical. Find the pressure on it due to a force of 20 N. How much would be the pressure under her thumb having contact area 1.5 cm 2 ? (5×10 5 Nm – 2)Ĭontact Area A = 1.5 cm 2 = 1.5 x x m 2 = 1.5 x 10 – 4 m 2ħ.6 The head of a pin is a square of side 10 mm. Mass of air = Density of air x volume of roomħ.5 A student presses her palm by her thumb with a force of 75 N. Volume of room = v = 8 m x 5 m x 4 m = 160 m 3 Solution: Density of air = r = 1.3 kgm – 3 Find the mass of air in a room measuring 8m x 5m x 4m. (ii) Mass of lead shot = m = 200 g = kg = 0.2 kgħ.4 The density of air is 1.3 kgm – 3.

Since density of ice is 0.92 times of the liquid water therefore,ħ.3 Calculate the volume of the following objects: (i) An iron sphere of mass 5 kg, the density of iron is 8200 kgm – 3. Solution: volume of wooden block = V = 40 cm x 10 cm x 5cm = 2000 cm 3ĭensity = mass / volume = 0.85 / 0.02 = 425 kg – 3ħ.2 How much would be the volume of ice formed by freezing 1 litre of water? (1.09 litre)ġ litre of water = 1 kg mass and density = 1000 kg – 3 (2×1011 Nm – 2)ħ.1 A wooden block measuring 40 cm x 10 cm x 5 cm has a mass 850 g. 7.12 A steel wire of cross-sectional area 2×10 – 5 m2 is stretched through 2 mm by a force of 4000 N.How much force is required to lift a car weighing 20 000 N on its piston if the diameter of the piston of the pump is 3 cm? (200 N) 7.11 The diameter of the piston of a hydraulic press is 30 cm.Determine (a) volume of the block (b) the volume of the block immersed when placed freely in a liquid of density 0.9 gcm – 3 ?(510 cm3, 340 cm3) 7.10 A solid block of wood of density 0.6 gcm – 3 weighs 3.06 N in air.7.8 A cube of glass of 5 cm side and mass 306 g, has a cavity inside it.(i) The pressure exerted by the block on the surface.7.7 A uniform rectangular block of wood 20 cm x 7.5 cm x 7.5 cm and of mass 1000g stands on a horizontal surface with its longest edge vertical.7.6 The head of a pin is a square of side 10 mm.

How much would be the pressure under her thumb having contact area 1.5 cm2 ? (5×105 Nm – 2) 7.5 A student presses her palm by her thumb with a force of 75 N.7.4 The density of air is 1.3 kgm – 3.(ii) 200 g of lead shot having density 11300 kgm – 3.(i) An iron sphere of mass 5 kg, the density of iron is 8200 kgm – 3.7.3 Calculate the volume of the following objects:.7.2 How much would be the volume of ice formed by freezing 1 litre of water? (1.09 litre).7.1 A wooden block measuring 40 cm x 10 cm x 5 cm has a mass 850 g.

Density of glass