🔍 Challenge Corner: High-Level Pressure and Friction Problems
1. A nail has a tip area of 0.00001 m². If a hammer strikes it with a force of 50 N, calculate the pressure exerted on the wood.
Pressure = Force / Area = 50 / 0.00001 = 5,000,000 Pa (or 5 MPa)
2. Why do tanks have wide tracks instead of wheels when moving on soft ground?
To reduce pressure on the ground. A larger contact area decreases pressure (P = F/A), preventing the tank from sinking into the soft ground.
3. A block weighing 40 N is placed on a horizontal surface. If the area of contact is 0.2 m², what is the pressure exerted by the block?
Pressure = Force / Area = 40 / 0.2 = 200 Pa
4. Explain why it is easier to walk on rough surfaces than on smooth surfaces.
Rough surfaces offer more friction, providing grip. Smooth surfaces reduce friction, making it harder to walk without slipping.
5. A wooden block of mass 2 kg is pushed with a force of 10 N across a rough surface. If frictional force is 4 N, calculate the net force and acceleration. (Take g = 10 m/s²)
Net Force = 10 - 4 = 6 N; Mass = 2 kg → Acceleration = F/m = 6/2 = 3 m/s²
