AQA Physics GCSE P2 & P3 [OFFICIAL THREAD]

These are the 5 key stages about terminal velocity of a parachutist.
1. Accelerates rapidly because falling force is much larger than air resistance.
2. Accelerating (slower) because air resistance has increased slightly.
3. Constant speed because air resistance is equal to falling force. Terminal Velocity has been reached.
4. *opens parachute* Parachutist slows down.
5. (slower) Constant speed because air resistance is equal to falling force. Terminal velocity has been reached.

Terminal velocity = when forwards force is equal to air resistance (usually top speed).
Larger surface area = slower terminal velocity.
As velocity increases, air resistance increases at FASTER rate, i.e NOT directly proportional.

Hope this helps!

I bet my house that the 6 marker in p2 will be about stars

Thank you so much this was really helpful!!

If anyone needs help with any topics then let me know, teaching someone helps me too!

If anyone needs help with any topics then let me know, teaching someone helps me too!

I don't understand a question in unit 2 June 2014?

The mass of the skateboard is 1.8 kg on the mass of the skateboarder is 42 kg

calculate the velocity at which the skateboard moves backwards if the skateboarder jumps forward to velocity of 0.3 M/S

3 marks. It's to do with moment but I'm not sure how to work it out?

Anything but momentum will be very much appreciated tbh

that would be heaven

work it out as two separate objects. momentum = mass x velocity. The law of momentum states that momentum must be conserved, therefore if you workout the momentum of of the skateboarder e.g. 42 x 0.3 = 12.6. so now we know that 1.8 x? = 12.6. Therefore simply do 12.6/1.8 = 7m/s.
Hope this helps, remember momentum is always conserved!

Basically, the conservation of momentum means that the momentum before an event is equal to the moment after.

In this case, the initial moment is when the skateboarder jumps forward. This means his momentum will be his mass * his velocity which is 42 * 0.3 = 12.6 kgm/s

Due to the conservation of momentum, the skateboard will also move back with the SAME momentum i.e. 12.6 kgm/s

Since we know the skateboard has a mass of 42 kg and a momentum of 12.6 kgm/s we can work out the velocity using the formula Momentum = Mass * Velocity so Velocity = Momentum/Mass i.e. 12.6/1.8 = 7 m/s

I think that's the right answer. Let me know if it is.

With people predicting that it will be a plan your own experiment type thing, it could be a question on how you can find out the centre of mass or how to find out focal length of a lens. I'd look over those two just in case I think.

work it out as two separate objects. momentum = mass x velocity. The law of momentum states that momentum must be conserved, therefore if you workout the momentum of of the skateboarder e.g. 42 x 0.3 = 12.6. so now we know that 1.8 x? = 12.6. Therefore simply do 12.6/1.8 = 7m/s.
Hope this helps, remember momentum is always conserved!

Thank you so much this was really helpful!!