Instantaneous velocity of a object in projectile motion


by NightRunnerz
Tags: instantaneous, motion, object, projectile, velocity
NightRunnerz
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#1
Nov13-10, 08:08 PM
P: 2
1. The problem statement, all variables and given/known data
stone is thrown horizontally with a initial speed of 8.0 m/s (Vxi)
Air resistance is negligible. average acceleration due to gravity = 9.8 N/Kg (down) [ay]

2. Relevant equations
dx= Vxi/ time
Vfy= vyi + ay x time
Instantaneou velocity equation? :S



3. The attempt at a solution
okay so it tells me to find horizontal and vertical components of displacement and instantaneous velocity at time=0.0s/1.0s/2.0s and 3.0s isn't Vyi given (initial y velocity SINCE it's 0?) and (vxi is also give - 8.0 m/s)
BUt how do i find INSTANTANEOUS velocity?
1. The problem statement, all variables and given/known data



2. Relevant equations



3. The attempt at a solution
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tiny-tim
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#2
Nov14-10, 06:37 AM
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Hi NightRunnerz! Welcome to PF!
Quote Quote by NightRunnerz View Post
how do i find INSTANTANEOUS velocity?
Instantaneous velocity just means the velocity at that particular moment (ie, the word "instantaneous" is unnecessary )

(and if you need the speed, use Pythagoras! )
NightRunnerz
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#3
Nov14-10, 09:56 PM
P: 2
OKAY so by velocity you mean V as in speed right?
dotdotdot m/s2?
.....m/s2?

tiny-tim
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#4
Nov15-10, 02:24 AM
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Instantaneous velocity of a object in projectile motion


Hi NightRunnerz!

(just got up )
Quote Quote by NightRunnerz View Post
okay so it tells me to find horizontal and vertical components of displacement and instantaneous velocity at time
Quote Quote by NightRunnerz View Post
OKAY so by velocity you mean V as in speed right?
No, speed and velocity are different.

Speed is the magnitude of velocity.

Velocity has components, speed doesn't.

The question tells you to find the horizontal and vertical components of instantaneous velocity that's vx and vy.
dotdotdot m/s2?
.....m/s2?
m/s2 is acceleration


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