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.

Countdown SPM:
80 days left

80 days until we say, “we made it.”

those who haven't yet complete this chapter may finish it today.

Don't buy any notes or exercise from this guy, scammer...

hi guys! ive heard that some schools gonna start their UAS next week (for fomfooo) and form 4, are you ready for UAS? :v

some quick tips for amali!

— for form 4, revise experiments that you’ve done before. if you have a clue about the experiment, look for trial papers with similar experiments.

— know the aim, variables, procedures, observations & conclusion of every experiment in the syllabus (or at least the famous ones 🦒)

— make sure your materials & apparatus are complete and in good condition before starting.

— don’t be too specific with observations; be specific with your inferences.

— please know how to answer DSO, MV, RV & CV.

— for tables & graphs, remember units, suitable scales, MV on x-axis & RV on y-axis.

— know your operational definitions and how to identify errors & improvements.

— always read the instructions carefully and watch your time!

— take your readings at eye level to avoid parallax error, especially for measuring cylinders, rulers & thermometers.

— for calculations, show your working, include the correct units and don’t round off too early.


goodluck everyoneee -lyadamdam

goodluck eberiwan! get dat 15/15 🥳🥳

Guys, regarding the relationship question for Amali:

With a graph: Must state the exact mathematical relationship (e.g., directly proportional if it passes through the origin, or increases linearly).
Without a graph (table/observations only):Writing general trends like “when MV increases, RV increases” is accepted.

u should write the eye level must be perpendicular to the scale reading of Ruler / Meter rule / Measuring tape/ measuring cylinder / burette / pipette/ammeter/voltmeter to avoid parallax error to get full marks.

keyword

and remember all your data should have the same decimal places. if lets say u have 2.5 , 3.6 and 4, u shouldn't write 4, u should write 4.0

Countdown SPM:
79 days left

Spm is only once in our lifetime, so just enjoy the process and keep going 09’s ! - by Pemburu10A