# Module 5

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1. What is a scalar quantity?
Only has a size
2. What is a vector quantity?
Has a size and a direction
3. What is a relative speed?
How fast something is going relative to something else
4. What are four equations of motion?
• s = (u + v)/2 xt
• v = u + at
• s = ut + 0.5at2
• v2 = u2 + 2as
5. What does 'u' represent?
Initial velocity
6. What does 'v' represent?
Final velocity
7. What does 's' represent?
Displacement (distance)
8. What does 't' represent?
Time
9. What does 'a' represent?
Acceleration
10. What is a projectile?
Something that is projected, or dropped, and from then on only has Earth's gravitational field strength acting on it (ignoring air resistance)
11. What shape is the path of a projectile?
Parabolic
12. What is the overall/resultant velocity of the ball?
The vector sum of the horizontal and vertical motion
13. What do projectile calculations use?
The equations of motion
14. When do forces occur?
When two objects interact
15. What are the two forces sometimes called?
An interaction pair
16. What are two examples of acting forces?
• Recoil
• Rockets
17. How does recoil involve forces?
• When a gun is fired, the bullet exerts a force on the gun equal and opposite to the force exerted by the gun on the bullet
• So, the bullet travels out of the barrel and the gun recoils in the opposite direction
• The bullet travels much faster forwards than the gun does backwards because the bullet is much lighter
18. How do rockets use forces?
• When gas particles collide with things they exert a force on them
• In a rocket engine particles of hot gas collide with the walls, exerting a force on the walls and the wall exerts an equal force on them
• The force from the wall pushes the gas particles out of the exhaust
• The force from the gas on the wall pushes the rocket forwards
• The force pushing the rocket upwards must be larger than the force of gravity and air resistance of it won't take off
• So, for large rockets, used to lift satellites into orbit above Earth, you need a large number of particles moving at high speed to produce enough force to lift the rocket
19. How can you work out momentum?
momentum = mass x velocity
20. What is momentum before equal to?
• Momentum after
• Momentum is conserved
21. What does 'm1' represent?
Mass of the first object
22. What does 'm2' represent?
Mass of second object
23. What does 'u1' represent?
Velocity of first object
24. What does 'u2' represent?
Velocity of second object
25. What does 'v' represent?
Velocity of combined objects
26. What does kinetic energy say about gases?
They are randomly moving particles
 Author: PoppyG ID: 297535 Card Set: Module 5 Updated: 2015-03-04 12:17:32 Tags: GCSE Science Physics Module5 Folders: GCSE,Science,Physics Description: GCSE Physics Module 5 Show Answers: