Applications of calculus to the physical World Q (1 Viewer)

[shaon0]

This is easy but i am not getting it.
s=t^2-6t+8
Find the distance travelled by the particle in the 4th second.

 

[tacogym27101990]

is the answer 8 units?
im assuming s is displacement?

 

[shaon0]

is the answer 8 units?
im assuming s is displacement?

no its distance but i think its interchangeable.
Yes, i got 8 to but on the solutions it says 1.

 

[lolokay]

the 4th second is from t=3, s=-1
to t=4, s=0

distance is 1

 

[shaon0]

the 4th second is from t=3, s=-1
to t=4, s=0

distance is 1

is that what it means ok.
I was thinking whther it meant that, thanks.
Also, x=12t-t^3 where x is distance.
Show that the particle movesfrom the origin for 2 seconds then comes back at a velocity of 24m/s in a negative direction.

 

[lolokay]

d/dx 12t-t^3
= 12 - 3t²
= 0 when t=+-2, so is moving away from the origin for 2 seconds (at t=0, x=0)

when x=0, t=0, +-rt12
so when it returns it has a velocity of 12 - 3*12 = -24

 

[shaon0]

d/dx 12t-t^3
= 12 - 3t²
= 0 when t=+-2, so is moving away from the origin for 2 seconds (at t=0, x=0)

when x=0, t=0, +-rt12
so when it returns it has a velocity of 12 - 3*12 = -24

thanks a lot.

 

[lyounamu]

no its distance but i think its interchangeable.
Yes, i got 8 to but on the solutions it says 1.

??

What do you mean? It's obviously displacement. Distance can never be negative.

 

[Numbers]

??

What do you mean? It's obviously displacement. Distance can never be negative.

AHAHAHAHA! Namu, you're so dumb! I'm stupid in maths and even I know that the distance can be negative. It just means that it's traveling in the opposite direction...idiot.

 

[lyounamu]

AHAHAHAHA! Namu, you're so dumb! I'm stupid in maths and even I know that the distance can be negative. It just means that it's traveling in the opposite direction...idiot.

wtf. Distance can not be negative. Distance is a scalar quantity which means it is the fucking length containing only the magnitude. Go back to General Mathematics.

It's like speed and velocity. Speed is always positive whereas velocity can be both negative and positive depending on the direction...fuckin idiot

 

[Numbers]

he trolling, dont get angry

ahahaaa, nah seriously, i wasn't trolling. sorry namu. i seriously thought i was right and yeah, sorry.

 

[lyounamu]

he trolling, dont get angry

Sorry, I really have a short temper. I will make sure I fix that part.

 

[Numbers]

Sorry, I really have a short temper. I will make sure I fix that part.

Namu, I owe you an apology. I'm sorry.

 

[vds700]

wtf. Distance can not be negative. Distance is a scalar quantity which means it is the fucking length containing only the magnitude. Go back to General Mathematics.

It's like speed and velocity. Speed is always positive whereas velocity can be both negative and positive depending on the direction...fuckin idiot

HAHAHAHAHAHAHA

You tell him Namu!!!

 

[tommykins]

Sorry, I really have a short temper. I will make sure I fix that part.

You've been veryshort tempered lately mate, HSC gettnig to you?

 

[lyounamu]

You've been veryshort tempered lately mate, HSC gettnig to you?

Well, not really. It's probably due to my Preliminary exam period that just ended...I was so stressed because I was under-prepared...well, I am not really in a position to make excuses...

 

[cutemouse]

Distance is a scalar quantity, notice how all the maths distance formulas (eg. p.d. and distance-formula) have absolute values or square roots/squares? Displacement on the other hand is a vector quantity, and has a direction, and can be negative depending on which way you call positive.

AHAHAHAHA! Namu, you're so dumb! I'm stupid in maths and even I know that the distance can be negative. It just means that it's traveling in the opposite direction...idiot.

 

[proringz]

Yes, displacement is a vector quantity meaning it has direction. On the other hand, it is the distance that is a scalar quantity and has no direction; only magnitude.

 

[shaon0]

??

What do you mean? It's obviously displacement. Distance can never be negative.

Give me a break....I mean within the contexts of the question.

 

[lolokay]

can't scalars be considered negative? eg. energy, voltage? you can subtract scalars.. (in this question displacement and distance are interchangeable anyway)