A rectangular solid black has length 10cm bread... - JAMB Physics 2024 Question

Here's how to solve this problem:

1. Convert Units: Convert the dimensions from centimeters to meters:

   • Length (l) = 10 cm = 0.1 m
   • Breadth (b) = 5 cm = 0.05 m
   • Height (h) = 2 cm = 0.02 m

2. Calculate the Volume: Calculate the volume of the rectangular solid:

   • Volume (V) = l * b * h = 0.1 m * 0.05 m * 0.02 m = 0.0001 m³

3. Calculate the Mass: Use the density to find the mass of the solid:

   • Density (ρ) = 100 kg/m³
   • Mass (m) = ρ * V = 100 kg/m³ * 0.0001 m³ = 0.01 kg

4. Calculate the Weight (Force): Calculate the weight of the solid, which is the force it exerts on the surface:

   • Weight (W) = m * g, where g is the acceleration due to gravity (approximately 10 m/s²)
   • W = 0.01 kg * 10 m/s² = 0.1 N

5. Calculate the Area in Contact: Determine the area of the surface in contact with the horizontal surface. Since the question does not specify which surface it rests on, we will assume the base with the largest area.

   • Area (A) = Length * Breadth = 0.1 m * 0.05 m = 0.005 m²

6. Calculate the Pressure: Calculate the pressure using the formula:

   • Pressure (P) = Force / Area = 0.1 N / 0.005 m² = 20 N/m². This does not match any of the options. However, if we instead calculate the area with the shortest side, the area is:
   • Area (A) = Breadth * Height = 0.05m * 0.02m = 0.001m²
   • Pressure (P) = Force / Area = 0.1 N / 0.001 m² = 100 N/m²

Therefore, the most appropriate answer is C.