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1. A 150 g mass attached to a horizontal spring oscillates at a frequency of 3.4

ID: 1481556 • Letter: 1

Question

1. A 150 g mass attached to a horizontal spring oscillates at a frequency of 3.40 Hz . At t =0s, the mass is at x= 4.40 cm and has vx =? 29.0 cm/s . Determine the phase constant.

2. An air-track glider attached to a spring oscillates between the 16.0 cm mark and the 54.0 cm mark on the track. The glider completes 13.0 oscillations in 31.0 s . What is the maximum speed of the glider?

3. A 240 g particle moving along the x-axis experiences the force shown in the figure. (Figure 1) The particle goes from vx = 2.40 m/s at x =0m tovx = 6.00 m/s at x =2.0m.

What is Fmax?

Explanation / Answer

x = A*cos(wt-phi)


w = 2*pi*f = 2*pi*3.4 = 21.36 rad/s

at t = 0, x = 4.4 cm Vx = 29 cm/s

vx = w*(A^2-x^2)


29 = 21.36*(A^2-4.4^2)


A = 4.55 cm


spring constant k = m*w^2 = 0.15*21.36^2 = 68.44 N/m

at t = 0


4.4 = 4.55*cos((68.44*4.4)-phi)


phi = 301.4 rad


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2)

amplitude = (16+54)/2 = 35 cm = 0.35 m

time period = T = t/N = 31/13 = 2.4 s

Vmax = A*w = 0.35*2*pi/2.4 = 0.92 m/s

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3)

area = change in KE

0.5*F*2 = 0.5*0.24*(6^2-2.4^2)

F = 3.6288 N