Physics HELP!
posted by Tom .
The position of an object connected to a spring varies with time according to the expression x = (7.1 cm) sin (2.1π t). Find
(a) the period of this motion (b) the frequency of the motion (c) the amplitude of the motion (d) the first time after t=0 that the object reaches the position x = 2.6 cm (Make sure your calculator is in radians mode)

(a)
Compare
x = (7.1 cm) sin (2.1π t)
with
x=Asin(ωt)
Then
ω= 2.1π,
=> T=2π/ ω =
= 2 π/2.1π=0.7 rad/s
(b)
f=1/T=1.42 Hz
(c)
A=7.1 cm
(d)
x=Asin(ωt)
2.6 = 7.1 sin (2.1π t)
sin (2.1π t) =2.6/7.1=0.366
(2.1π t)=sin⁻¹0.366=0.375 rad
t=0.375/2.1π=0.0569 s.