Force & Momentum Flashcards
What is momentum?
motion is conserved in an isolated system
Conservation of Momentum relating to 3rd Newton’s Law
F1 = -F2
Hence, p1/t = -p2/t
Hence, p1 = -p2
Practicing multi-image diagrams…
Practice guys 0-0
What does space propulsion do?
It describes & explains the motion& propulsion
Can you derive Newton’s second law to show that F=ma is the same as F=𝛥p/𝛥t?
YALL SHOULD
What is a solar sail? 0-0
A solar sail is a piece of material in space (the flag thing) which is propelled by the MOMENTUM OF PHOTONS from the Sun!
How do you draw a change in momentum yall??
The vector of FINAL momentum + the negative momentum of the INITIAL momentum
Let’s say a ball is travelling at 10ms and it hits the wall at 90 degree
Would the average force by the wall on the molecule be the same as the average force by the molecule on the wall?
YES! the direction is just opposite of each other
Imagine a multi image diagram between 3 students colliding
if the mass of one student is 3m, what’s the length of the vector for momentum?
3 lenghts between each space of the student
Check the multi-image diagramm! :D
Solar Sail: Absorption
Can you draw a vector diagram for this????
It should look like a vertical line. On one side there should be 2 arrows (same length) going in opposite directions. On the other side, there should be another arrow (same length) to show the movement of the sail…..
Solar Sail: Absorption
Can you explain the physics behind the ABSORBTION solar sail????
A photon travelling 1 unit to the right hits the sail and is absorbed. The CHANGE in momentum (final – inital) means that there is an arrow going in the opposite direction (1 unit to the left). Because of equal and opp. forces, the sail has to move 1 unit to the right so that the total change in momentum = 0.
What are the things in an ion thruster?
Electrons fired at neutral propellant (xenon gas)
Ionisation releases protons
Electric & Magnetic force pros out of spacecraft (increasing speed)
How does ion thruster work?
Release particles (decreasing mass), and are accelerated (increasing speed)
-> LARGER Momentum
A neitrolisation emits elecs -> prevent a buildup of - charge (good control of movement)
What are the good & bad things of an ion thruster?
GOOD: fuel efficiency
BAD: Not enough force for propulsion from Earth.
Solar Sail: Reflection
Draw the vector diagram for this 0-0
It should look like a vertical line. On one side there are 2 short arrows pointing in opp. directions, and a long arrow (double the length of short arrow) pointing in away from sail.
On the other side of the sail there should be one long arrow showing the movement of the sail.
