Can someone explain this to me please?

  • Thread starter gcombina
  • Start date
  • #1
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Warning: Non-descriptive thread title

Homework Statement


Which equation is valid only when the angular measure is expressed in radians?
a) α = Δθ / Δt

b) ω= Δω / Δt

c) ω^2 = ωo^2 + 2αθ

d) ω = Vt/r (here T is a subscript)

e) θ = 1/2αt^2 + ωαt

Answer is D but why??



Homework Equations



I know angles can be measured in either degrees or radians

The Attempt at a Solution



angular velocity = ??? divided by radius

I guess I don't understand what Vt is
 

Answers and Replies

  • #2
516
63

Homework Statement


Which equation is valid only when the angular measure is expressed in radians?
a) α = Δθ / Δt

b) ω= Δω / Δt

c) ω^2 = ωo^2 + 2αθ

d) ω = Vt/r (here T is a subscript)

e) θ = 1/2αt^2 + ωαt

Answer is D but why??



Homework Equations



I know angles can be measured in either degrees or radians

The Attempt at a Solution



angular velocity = ??? divided by radius

I guess I don't understand what Vt is
How do you relate the length of an arc to the angle subtended by the arc and the radius? What should the units of each quantity be?
 
  • #3
gneill
Mentor
20,813
2,786
I guess I don't understand what Vt is
Presumably ##V_t## will be defined in the text surrounding the problem. In this context I would imagine that it represents the tangential velocity of a rotating object at distance r from the center of rotation.
 

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