🟢 Lazy Man Flashcards – NSSCO Physics (Friction)

Q1. What is friction?
A1. Friction is the resistive force that opposes the relative motion between two surfaces in contact.
👉 Keywords: opposes motion, contact force, resistive force.

Q2. Which force prevents slipping when walking?
A2. Static friction prevents slipping by gripping the ground until the limit is exceeded.
👉 Keywords: static friction, grip, prevents sliding.

Q3. Which factor most affects the size of friction?
A3. The nature/roughness of the surfaces in contact. Rougher surfaces = more friction.
👉 Keywords: surface texture, roughness, microscopic irregularities.

Q4. Does surface area directly affect friction?
A4. No — friction mainly depends on normal force and surface texture, not on surface area.
👉 Keywords: normal reaction force, not area.

Q5. What type of friction acts on a ball rolling on grass?
A5. Rolling friction, smaller than sliding friction, slows the ball down.
👉 Keywords: rolling resistance, contact deformation.

Q6. Which force opposes a car moving through air?
A6. Air resistance (a form of fluid friction) opposes motion through air.
👉 Keywords: drag, fluid friction, velocity dependent.

Q7. Why does a rough road slow down vehicles?
A7. Increased surface irregularities cause larger friction opposing motion.
👉 Keywords: rough surface, resistive force, energy loss.

Q8. What is the disadvantage of too much friction in machines?
A8. It causes wear and tear and energy loss as heat.
👉 Keywords: wear, heat loss, reduces efficiency.

Q9. What is one advantage of friction in daily life?
A9. Provides grip and traction, e.g., walking or car tyres gripping the road.
👉 Keywords: grip, traction, prevents slipping.

Q10. Which method reduces friction in engines?
A10. Lubrication with oil/grease smoothens contact surfaces.
👉 Keywords: lubricant, reduces wear, smoother motion.

Q11. Why are ball bearings used in bicycles?
A11. They reduce sliding friction to rolling friction, which is smaller.
👉 Keywords: rolling friction, efficiency, smoother rotation.

Q12. Why are streamlined shapes used in cars and airplanes?
A12. To reduce air resistance and increase efficiency/speed.
👉 Keywords: streamlined, drag reduction, aerodynamic.

Q13. Which friction acts when a box just begins to move?
A13. Static friction at its maximum value.
👉 Keywords: limiting friction, maximum static.

Q14. Why do shoes wear out faster on rough surfaces?
A14. Greater abrasive friction wears away shoe material.
👉 Keywords: abrasion, rough surface, material loss.

Q15. What energy change happens due to friction?
A15. Kinetic energy is converted into heat and sometimes sound.
👉 Keywords: energy dissipation, thermal energy.

Q16. Why do machines need oiling?
A16. To reduce friction, preventing overheating and increasing efficiency.
👉 Keywords: lubrication, efficiency, wear prevention.

Q17. Why do brakes stop a bicycle?
A17. Brake pads increase friction with the wheels, converting motion to heat.
👉 Keywords: brake pads, heat, stopping force.

Q18. Why is friction called a “necessary evil”?
A18. It is useful for grip and walking but also causes energy loss and wear.
👉 Keywords: advantages, disadvantages.

Q19. Why do tyres have treads?
A19. To increase friction/grip, especially on wet surfaces, preventing skidding.
👉 Keywords: traction, road grip, safety.

Q20. Why are skis smooth?
A20. To reduce friction for faster sliding on snow.
👉 Keywords: reduced resistance, sliding motion.

Q21. Why does friction increase with load?
A21. More normal force pushes surfaces together, increasing contact irregularities.
👉 Keywords: normal reaction, load dependent.

Q22. Why is friction less on smooth surfaces?
A22. Fewer microscopic irregularities, less resistance.
👉 Keywords: surface smoothness, reduced contact.

Q23. Why are oil tankers streamlined?
A23. To reduce water resistance for efficient movement.
👉 Keywords: fluid friction, streamlined shape.

Q24. Why are chalkboards rough?
A24. Increased friction allows chalk particles to stick and form marks.
👉 Keywords: rough surface, grip for chalk.

Q25. Why do we slip on smooth floors?
A25. Low friction reduces grip between shoes and floor.
👉 Keywords: lack of traction, low surface grip.

Q26. What happens to kinetic energy when friction acts?
A26. It is converted mainly into heat.
👉 Keywords: energy loss, thermal conversion.

Q27. Why does friction produce heat?
A27. Microscopic irregularities interlock and resist motion, releasing energy as heat.
👉 Keywords: interlocking, vibration, heat.

Q28. Why do machines wear out?
A28. Continuous friction causes surface damage and material loss.
👉 Keywords: abrasion, wear, tear.

Q29. Why is oil applied to door hinges?
A29. To reduce squeaky friction, allowing smooth motion.
👉 Keywords: lubrication, smoother rotation.

Q30. Why do car engines overheat without oil?
A30. Excess friction converts kinetic energy into heat, damaging parts.
👉 Keywords: heat buildup, efficiency loss, wear.

🧠 Lazy Man Flashcards (High-Yield with Exam Depth)

Q1. What is friction and how does it affect motion?
A1. Friction is a contact force that opposes the relative motion between two surfaces. It causes objects to slow down, stop, or generate heat.
Keywords: opposes motion, resistance, slows, heat.

Q2. How does the type of surface affect friction?
A2. Rougher surfaces increase friction due to more irregularities interlocking, while smoother surfaces reduce friction.
Keywords: rough → more, smooth → less, surface irregularities.

Q3. Does the size of the contact area affect friction?
A3. No. Friction depends on the nature of the surfaces, not the area in contact.
Keywords: independent of area, surface type matters.

Q4. Give two advantages of friction in everyday life.
A4. Friction allows walking without slipping and enables vehicles to brake safely.
Keywords: grip, traction, stability, braking.

Q5. State two disadvantages of friction.
A5. Friction causes wear and tear in machines and results in energy loss as heat.
Keywords: wear, heat, efficiency, loss.

Q6. How can friction be reduced in machines?
A6. By using lubricants (oil, grease), ball bearings to reduce surface contact, and streamlining to minimize air resistance.
Keywords: lubrication, rolling, streamlining.

Q7. Why is friction both useful and undesirable?
A7. Useful because it provides grip and stability; undesirable because it causes wear and energy loss.
Keywords: double-edged, grip vs wear, efficiency.

Q8. Why does a car tyre have tread patterns instead of smooth rubber?
A8. Tread patterns increase grip by channeling away water, preventing skidding on wet surfaces.
Keywords: grip, traction, safety, skid prevention.

Q9. Why are ball bearings used in bicycle wheels?
A9. They replace sliding friction with rolling friction, which is much smaller, making movement smoother and efficient.
Keywords: rolling friction < sliding friction, efficiency, smooth motion.

Q10. Why do athletes wear spiked shoes?
A10. To increase friction with the ground, preventing slipping and improving performance.
Keywords: grip, traction, stability, control.