Try to masterize this chapter today.

hail, warriors of the chat-hall! i, stride in when the feast is cold, too late to plunder the words. fate marked my delay! forgive my months-long vanishing. ⚔️🍻

wait, sine when telegram ai became this advanced? anyways, since the intensive study programme is ongoing and it's getting late, let's end the day with chap 2💃💃

these are noob-level questions, but they're great for winding down at night.😂😂

i hope i'll send the answers by tomorrow😭 i'm so forgetful these days... g-bye!!

here's the answer for the spinning top question

so what's the actual working ?
First, the question mentioned the ball decelerates, meaning the resultant force is acting upwards. The ball has its weight acting downwards. The overall equation is as below:
F_{net} = ma
F_{sand} - Weight = ma
F_{sand} = mg + ma
F_{sand} = 4.50 (9.81 + 8 x 10^2)
F_{sand} = 3644 N ~ 3640 N

how about this question then? Almost half of the people chose B.

How can an unbalanced force exist in order to get a resting object to move or stop and even accelerate if every action has an equal and opposite reaction based on Newton's Third Law ?

this was asked by a student in 2021. Rarely got people ask this kind of question 🤣
You see, when school teaches Newton’s Second Law, they just throw you F = ma. Then when they teach Newton’s Third Law, they say got action-reaction pair: equal magnitude, opposite direction.

That’s why people get confused: "Eh, if got action-reaction pair, shouldn't they cancel each other out? Then how come still got F = ma? Shouldn't net force be zero already?"

The thing many teachers don't explicitly highlight is what the forces are acting on:
2nd Law (F = ma) is strictly for one single object. You only count the forces acting on that body.
3rd Law action-reaction pairs act on two different objects.

Take an example: you push a table forward.
Force 1 is your hand pushing the table.
Force 2 (the reaction) is the table pushing back on your hand.
See? The reaction force is acting on you, not on the table! The table doesn't care what force is pushing your hand. As long as your push on the table is bigger than the floor friction, the table will have an unbalanced force and accelerate.