Newton's second law

Question 1

Tell me about the elevator

Answer 1

In a balanced force:
1. R = mg
2. R is the top
3. mg is the bottom
4. Balanced cuz no acceleration anywhere

If F=ma is upwards:
1. Accelerating upwards
2. R - mg = ma
3. Re-arranging for R = mg + ma
4. U just gotta know

If F=ma is downwards:
1. Accelerating downwards
2. mg - R = ma
3. Re-arranging for R = mg - ma
4. Exact opposite, but still gotta know

• In addition, deceleration upwards = acceleration downwards

Typical answers u’d be asked to find:
1.

Question 2

Tell me about tow truck

Answer 2

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Question 3

Tell me about connected particles

Answer 3

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Question 4

What can u say for modelling assumptions?

Answer 4

Particle = no size but does have mass
Rigid body = has size but can’t change shape (deform) when force applied
Smooth = there’s no friction
Rough = friction is present
Light = no mass
Inelastic = doesn’t stretch
Elastic = does stretch

Ty for this