Class 8 Science Puzzles
1. Pressure: A force of 200 N is applied on an area of 0.5 m². What is the pressure?
Hint: Pressure = Force / Area
Answer: 400 Pa
2. Moment of Force: A 10 N force is applied at a perpendicular distance of 2 m from the pivot. Calculate the moment of force.
Hint: Moment = Force × Perpendicular distance
Answer: 20 Nm
3. Kinetic Energy: A body of mass 5 kg is moving with a velocity of 4 m/s. Calculate its kinetic energy.
Hint: KE = 0.5 × mass × velocity²
Answer: 40 J
4. Potential Energy: Calculate the potential energy of a 2 kg object placed at a height of 10 m (g = 10 m/s²).
Hint: PE = mass × g × height
Answer: 200 J
5. Electric Power: A device uses 1200 W of power for 2 hours. How much energy does it consume?
Hint: Energy = Power × Time
Answer: 2.4 kWh
6. Pressure: A weight of 500 N is acting on a surface of 0.25 m². Calculate the pressure exerted.
Hint: Pressure = Force / Area
Answer: 2000 Pa
7. Moment of Force: A torque of 50 Nm is produced by a force of 10 N. Find the perpendicular distance.
Hint: Distance = Moment / Force
Answer: 5 m
8. Kinetic Energy: An object of mass 8 kg is moving at 3 m/s. Calculate its kinetic energy.
Hint: KE = 1/2 × mass × velocity²
Answer: 36 J
9. Potential Energy: Find the potential energy of a 3 kg mass placed at a height of 15 m (g = 10 m/s²).
Hint: PE = mass × g × height
Answer: 450 J
10. Electric Energy: A bulb of 60 W is used for 5 hours. Calculate the energy consumed in kWh.
Hint: Energy = Power × Time
Answer: 0.3 kWh