Watch first
â¶
MyGCSEScience · AQA Physics
Force & Motion â watch on MyGCSEScience
â
FreeScienceLessons · AQA PhysicsNewton's Laws and F=ma
Cognito · AQA Physics 2026/27Terminal Velocity and Momentum
Key facts
Newton's Laws
- 1st Law: an object remains at rest or constant velocity unless a resultant force acts on it.
- 2nd Law: F = ma (resultant force = mass à acceleration). Units: F in N, m in kg, a in m/s².
- 3rd Law: for every action there is an equal and opposite reaction (forces act on different objects).
- Inertia = tendency to resist changes in motion. More mass = more inertia.
- Inertial mass = F/a (resistance to acceleration).
Terminal velocity
- Falling object: weight (down) vs air resistance (up).
- Initially: weight > air resistance â accelerates downward.
- As speed increases: air resistance increases.
- Terminal velocity: weight = air resistance â resultant = 0 â constant velocity.
- On VT graph: curve that levels off horizontally at terminal velocity.
Stopping distances
- Thinking distance = distance travelled during reaction time (before brakes applied).
- Affected by: speed, tiredness, alcohol, drugs, distractions.
- Braking distance = distance to stop after brakes applied.
- Affected by: speed (large effect â v²), road condition, tyre condition, brake condition, mass.
- Total stopping distance = thinking distance + braking distance.
Momentum
- Momentum = mass à velocity (p = mv). Unit: kg m/s. Vector quantity.
- Conservation of momentum â total momentum before collision = total momentum after (in a closed system).
- Impulse = force à time = change in momentum (Ft = Îmv).
- Larger collision time â smaller force for same change in momentum (crumple zones, air bags).
Exam questions â 4 questions · 12 marks
â¡ Extended questions included. Show all working for calculation questions. The AI marks against the real AQA mark scheme.
1 markTerminal velocityAQA 8463 P2 style
A skydiver jumps from a plane. Initially they accelerate. Eventually they reach terminal velocity. Explain why they stop accelerating.
A They run out of gravitational potential energy
B The air resistance force increases until it equals the weight â the resultant force becomes zero so acceleration stops
C Their mass increases as they fall through denser air
D The gravitational force decreases as they move closer to the ground
4 marksF=ma calculationAQA 8463 P2 style
A car of mass 1500 kg accelerates from 0 to 30 m/s in 10 seconds. Calculate (a) the acceleration and (b) the resultant force required. (4 marks)
Hint: (a) a = Îv/t. (b) F = ma. Show both steps clearly.
+40 XP
4 marksMomentum conservationAQA 8463 P2 Higher style
A 2000 kg car moving at 15 m/s collides with a stationary 1000 kg car. They stick together. Calculate their velocity after the collision. (3 marks)
Hint: Total momentum before = total momentum after. The cars stick together so use combined mass after.
+40 XP
1 markStopping distance factorAQA 8463 P2 style
A driver doubles their speed from 20 m/s to 40 m/s. Assuming the same braking force, what happens to the braking distance?
A It doubles
B It quadruples
C It stays the same
D It increases by 1.5 times
Module complete! ð
Score loading...