ICSE Class 8 Physics
Numericals on Force & Pressure
1. Find the moment of force of 20 N about an axis at a distance of 0.5 m.
Given:
Force (F) = 20 N
Distance (d) = 0.5 m
Formula:
Moment = Force × Distance
Moment = 20 × 0.5
= 10 N m
Answer = 10 N m
Force (F) = 20 N
Distance (d) = 0.5 m
Formula:
Moment = Force × Distance
Moment = 20 × 0.5
= 10 N m
Answer = 10 N m
2. The moment of a force is 2.5 N m. If the force is 25 N, find the perpendicular distance.
Given:
Moment = 2.5 N m
Force = 25 N
Formula:
Distance = Moment ÷ Force
Distance = 2.5 ÷ 25
= 0.1 m
Answer = 0.1 m
Moment = 2.5 N m
Force = 25 N
Formula:
Distance = Moment ÷ Force
Distance = 2.5 ÷ 25
= 0.1 m
Answer = 0.1 m
3. A spanner of length 10 cm is used with a force of 5 N. Find the moment of force.
Given:
Force = 5 N
Distance = 10 cm = 0.1 m
Moment = Force × Distance
= 5 × 0.1
= 0.5 N m
Answer = 0.5 N m
Force = 5 N
Distance = 10 cm = 0.1 m
Moment = Force × Distance
= 5 × 0.1
= 0.5 N m
Answer = 0.5 N m
4. A wheel of diameter 2 m is rotated by a moment of 2 N m. Find the force applied at the rim.
Given:
Moment = 2 N m
Diameter = 2 m
Radius = 1 m
Force = Moment ÷ Radius
= 2 ÷ 1
= 2 N
Answer = 2 N
Moment = 2 N m
Diameter = 2 m
Radius = 1 m
Force = Moment ÷ Radius
= 2 ÷ 1
= 2 N
Answer = 2 N
5. A normal force of 200 N acts on an area of 0.02 m². Find the pressure.
Given:
Force = 200 N
Area = 0.02 m²
Pressure = Force ÷ Area
Pressure = 200 ÷ 0.02
= 10000 Pa
Answer = 10000 Pa
Force = 200 N
Area = 0.02 m²
Pressure = Force ÷ Area
Pressure = 200 ÷ 0.02
= 10000 Pa
Answer = 10000 Pa
6. Find the thrust required to exert a pressure of 50,000 Pa on an area of 0.05 m².
Given:
Pressure = 50,000 Pa
Area = 0.05 m²
Thrust = Pressure × Area
Thrust = 50,000 × 0.05
= 2500 N
Answer = 2500 N
Pressure = 50,000 Pa
Area = 0.05 m²
Thrust = Pressure × Area
Thrust = 50,000 × 0.05
= 2500 N
Answer = 2500 N
7. Find the area of a body which experiences a pressure of 50,000 Pa by a thrust of 100 N.
Given:
Pressure = 50,000 Pa
Thrust = 100 N
Area = Thrust ÷ Pressure
Area = 100 ÷ 50,000
= 0.002 m²
Answer = 0.002 m²
Pressure = 50,000 Pa
Thrust = 100 N
Area = Thrust ÷ Pressure
Area = 100 ÷ 50,000
= 0.002 m²
Answer = 0.002 m²
8. Calculate the pressure exerted by a force of 300 N acting on an area of 30 cm².
Given:
Force = 300 N
Area = 30 cm² = 0.003 m²
Pressure = Force ÷ Area
Pressure = 300 ÷ 0.003
= 100000 Pa
Answer = 100000 Pa
Force = 300 N
Area = 30 cm² = 0.003 m²
Pressure = Force ÷ Area
Pressure = 300 ÷ 0.003
= 100000 Pa
Answer = 100000 Pa
9. How much thrust is required to exert a pressure of 20,000 Pa on an area of 1 cm²?
Given:
Pressure = 20,000 Pa
Area = 1 cm² = 0.0001 m²
Thrust = Pressure × Area
Thrust = 20,000 × 0.0001
= 2 N
Answer = 2 N
Pressure = 20,000 Pa
Area = 1 cm² = 0.0001 m²
Thrust = Pressure × Area
Thrust = 20,000 × 0.0001
= 2 N
Answer = 2 N
10. A boy weighing 60 kgf stands on a platform of dimensions 25 cm × 0.5 cm. Find the pressure.
Given:
Weight = 60 kgf
Area = 25 × 0.5 = 12.5 cm²
Pressure = Thrust ÷ Area
Pressure = 60 ÷ 12.5
= 4.8 kgf/cm²
Answer = 4.8 kgf/cm²
Weight = 60 kgf
Area = 25 × 0.5 = 12.5 cm²
Pressure = Thrust ÷ Area
Pressure = 60 ÷ 12.5
= 4.8 kgf/cm²
Answer = 4.8 kgf/cm²
