Question

(Calculus) How do I know if a particle is moving up or down at time t?

Answer 1

it the speed -ve then its up if its +ve then its down

Answer 2

so if i am given v(t) and have to find if the particle is moving up or down at time t=1.5, then i do v(1.5). if it is positive, then its going up?

Answer 3

yess :D

Answer 4

wait...isn't speed the absolute value of velocity, so its always positive?

Answer 5

well lets say im talking abt the velocity :D

Answer 6

now i'm confused...:(

Answer 7

usually when you write down an equation you define what the terms are... in other words, what direction is up. If you have a specific equation for some situation we can answer... otherwise it's 50/50 we get it right.

Answer 8

emm sry to confuse u :(
what i ment is the velocity from the begining

Answer 9

lol, the question is evolving ... what is it you are wanting to determine?

Answer 10

ok so v(t) = t sin(t^2) for t=>0
is the particle moving up or down at t=1.5 ?

Answer 11

well since its up , down question its ovs that the gravitation that determine the direction

Answer 12

did you start with an equation for the position x ?

Answer 13

nope.

Answer 14

Did they provide background on the question?

Answer 15

no they just gave me velocity. the particle moves along the y axis with velocity given by v(t) for t=>0

Answer 16

i still believe if +ve then its down :3

Answer 17

when they say it moves on the y-axis (which is up/down) then it's safe to assume that moving down is negative velocity. so evaluate
v(t) = t sin(t^2) at t= 1.5 (assume radians)

Answer 18

v(1.5) = 1.167 so the particle is moving up?

Answer 19

yes

Answer 20

Ok thank you @phi and @ikram002p :)

Answer 21

nope lol thnk phi :3