Angular Mechanics (4, 2)

Equations:

τ = I ⋅ α

Ki =

1 I ⋅ω i2

Kf = 1 I ⋅ ω f2

W = r ⋅ Θ

 

 

2

2

 

W = Kf – Ki

 

P =τ ⋅ ω

Pavg = W

ω f = ω i + α ⋅ t

 

 

 

t

 

at = α ⋅ r

ω = 2 ⋅ π ⋅ N

ω i = 2 ⋅ π ⋅ Ni

ω f = 2 ⋅ π ⋅ Nf

Example:

Given: I=1750_lbin^2, Θ =360_°, r=3.5_in, α=10.5_r/min^2, ωi=0_r / s.

Solution: r=1.1017E–3_ft_lbf, Ki=0_ftlbf, W=6.9221E–3_ftlbf, Kf=6.9221E–3_ftlbf,

at=8.5069E–4_ft/s^2, Ni=0_rpm, ωf=11.4868_r/min, t=1.0940_min, Nf=1.8282_rpm, Pavg=1.9174E–7_hp.

Centripetal Force (4, 3)

Equations:

F = m

⋅ ω 2

r

ω

=

v

ar =

v2

ω = 2 ⋅ π ⋅ N

 

 

 

r

r

 

Example:

Given: m=1_kg, r=5_cm, N=2000_Hz.

Solution: ω=12566.3706_r/s, ar=7895683.5209_m/s, F=7895683.5209_N, v=628.3185_m/s.

Hooke’s Law (4, 4)

The force is that exerted by the spring.

Equations:

F = –k ⋅ x

W =

–1

⋅ k ⋅ x

2

-----

 

 

 

2

 

 

Example:

Given: k=1725_lbf/in, x=125_in.

Solution: F=2156.25_lbf, W=112.3047_ft lbf.

Equation Reference 523

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Image 459
HP 48gII Graphing, 50g Graphing manual Angular Mechanics 4, Centripetal Force 4, Hooke’s Law 4