Mass, Weight and Density
Workshop Calculation and Science, Module-4
Q1: What is termed as the quantity of matter contained in a body?
- Density
- Volume
- Mass
- Specific gravity
Q2: What is the force with which a body is attracted by the earth towards its centre?
- Mass
- Weight
- Volume
- Density
Q3: What is called mass per unit volume of a substance?
- Mass
- Weight
- Density
- Volume
Show Explanation
Density is defined as: \[ \rho = \frac{m}{V} \] where \(m\) = mass, \(V\) = volume.
Q4: What is called the ratio between the density of a substance and density of water at 4°C?
- Density
- Specific gravity
- Mass
- Weight
Show Explanation
Specific gravity is: \[ \text{S.G.} = \frac{\text{Density of substance}}{\text{Density of water at 4°C}} \]
Q5: What is the density of aluminium?
- 2.7 g/cm³
- 3.7 g/cm³
- 4.7 g/cm³
- 5.7 g/cm³
Q6: What is the mass if the density of a body is 7.6 g/cm³ and its volume is 25 cm³?
- 190 grams
- 200 grams
- 210 grams
- 220 grams
Show Calculation
\[ m = \rho \times V = 7.6 \times 25 = 190\ \text{grams} \]
Q7: What is the specific gravity of the solid, if its density is 19.5 g/cm³?
- 18.0
- 18.5
- 19.0
- 19.5
Show Calculation
\[ \text{S.G.} = \frac{19.5}{1} = 19.5 \]
Q8: What is the density \(\rho\) in g/cm³ of an iron cube, if weight \(W = 4.8\) kg and volume \(V = 640\) cm³?
- 6.6 g/cm³
- 6.9 g/cm³
- 7.2 g/cm³
- 7.5 g/cm³
Show Calculation
Convert weight to grams: \(W = 4.8 \times 1000 = 4800\ \text{g}\)
\[ \rho = \frac{m}{V} = \frac{4800}{640} = 7.5\ \text{g/cm}^3 \]
Q9: What is the volume (V) of mercury in cm³, if mass \(m = 1\) kg and density \(\rho = 13.6\) g/cm³?
- 73.53 cm³
- 73.43 cm³
- 73.33 cm³
- 73.23 cm³
Show Calculation
\[ m = 1\ \text{kg} = 1000\ \text{g} \quad\] \[\Rightarrow \quad V = \frac{1000}{13.6} \approx 73.53\ \text{cm}^3 \]
Q10: What is the mass in grams, if a force of 15 dynes acts on a mass 'm' producing acceleration of 2.5 cm/s²?
- 9 grams
- 8 grams
- 7 grams
- 6 grams
Show Calculation
Using \(F = ma\):
\[ m = \frac{F}{a} = \frac{15}{2.5} = 6\ \text{grams} \]
Q11: What is the specific gravity of the metal, if the piece weighs 150 grams in air and 125 grams in water?
- 6
- 10
- 15
- 25
Show Calculation
\[ \text{S.G.} = \frac{\text{Weight in air}}{\text{Loss of weight in water}}\] \[= \frac{150}{150 - 125} = \frac{150}{25} = 6 \]
Q12: What is the volume of mercury in cm³, if mass \(m = 136\) grams and density \(\rho = 13.6\) g/cm³?
- 136 cm³
- 13.6 cm³
- 10.6 cm³
- 10.0 cm³
Show Calculation
\[ V = \frac{m}{\rho} = \frac{136}{13.6} = 10\ \text{cm}^3 \]
Q13: What is the block's weight (W) in kg, if volume \(V = 320\) cm³ and density \(\rho = 8.9\) g/cm³?
- 2.948 kg
- 2.848 kg
- 2.648 kg
- 2.448 kg
Show Calculation
\[ \text{Mass in grams} = \rho \times V\] \[= 8.9 \times 320 = 2848\ \text{g} = 2.848\ \text{kg} \]
Q14: What is the specific gravity of the metal, if it weighs 6.5 kg in air and 3.5 kg in water?
- 6.166
- 3.166
- 2.166
- 1.166
Show Calculation
\[ \text{S.G.} = \frac{6.5}{6.5 - 3.5} = \frac{6.5}{3} \approx 2.166 \]
Q15: What is the weight force of a car that has a mass of 800 kg? (Take g = 9.81\( \text{m/s}^2\))
- 7848 Newton
- 7748 Newton
- 7847 Newton
- 7487 Newton
Show Calculation
\[ W = m \times g = 800 \times 9.81 = 7848\ \text{N} \]