- #1
ibysaiyan
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Homework Statement
A particle has mass m = 0.1 kg , has a velocity which is given as: v = 3.2i+4.3j+5.4k m/s
It's acted by force f = 7.1i+8.2j+9.3k
The questions which arise are:
i) Find the speed of the particle.
ii) Write down a unit vector in the direction of the velocity.
iii)Find the angle between the projection of the velocity in the x,y plane and the x - axis.
iv) Find an expression of acceleration.
v) Find the velocity at a time of 2s.
Homework Equations
Now the equations that come to my mind are:
F = ma and f = change of momentum / time
The Attempt at a Solution
To get the speed: wouldn't that be the same as finding out an r.m.s value as such particle speed becomes: ~7.6m/s ?
For part (ii)is this how we find out a unit vector ? (ii)[itex]\vec u / ||\vec u||[/itex]
Now I'm a little lost about part (iii). You see I know how to find an angle between two vectors but here, I suppose since it's speaking of x,y axis within the same vector so I will use the following equation: A .B = |A| x |B| cos theta Can someone please clarify this for me?
Part iv doesn't seem that tricky... expression for acceleration has to be: a = f/m ...
v) Finding out velocity could be find out by using f = momentum /time...
Some background information: I have just started my course in Astrophysics, and this question comes out of a tutorial sheet where they don't expect us to know much and just see how much knowledge we have retained.(Proper lessons haven't even started, however I want to finish this early)
P.S: I'd like to apologize in advance of not using proper notation or over the lack of latex usage.
-ibysaiyan