PHYS 261 Cumulative Lab Questions
and Answers Graded A+
A block is measured to have a density p=2.76 g/cm3 with an uncertainty of
deltap=0.030 g/cm3. Find chi-squared when the measured density is compared to the
accepted density p=2.70 g/cm3. - ANSWER-Chi-squared=4
Chi-squared=sum((xi-xtheory)/deltaxi)^2
A block is measured to have mass M=25.3 g and volume V=9.16 cm3 with an
uncertainty of deltaM=0.050 g in the mass and deltaV=0.050 cm3 in the volume. What
is the uncertainty in the density? - ANSWER-0.016 g/cm3
(Deltap/p)^2=(deltaM/M)^2+(deltaV/V)^2
A cart of mass m=0.20 kg rides on an air track that is tilted at an angle 2 degrees from
the horizontal. What is the magnitude of the total force on the cart? - ANSWER-0.068 N
Mass*9.8*sin(theta)
A cart of mass m=0.25 kg rides on an air track that is tilted 3 degrees from the
horizontal. What is the magnitude of the cart's acceleration? - ANSWER-0.51 m/s^2
9.8*sin(theta)
A cart starts at X=0.5 m with an initial velocity of 1 m/s heading up the airtrack.
Assuming that the airtrack is tilted at 0.01 radians, use the spreadsheet to calculate and
plot the position versus time and the velocity versus time of the cart. - ANSWER-
d=d0+v0*t+(a0*t^2)/2
a0=g*sin(theta)
v=vi+a0*t
A cart with mass 0.3 kg and velocity 0.1 m/s collides on an air track with a cart with
mass 0.4 kg and velocity -0.2 m/s. If the final velocity of the first cart is -0.1 m/s after the
collision, what is the velocity of the second cart? - ANSWER--0.05 m/s
mv=mv
A cart with mass 0.30 kg and velocity 0.10 m/s collided on an air-track with a cart with
mass 0.40 kg and velocity -0.20 m/s. What is the final velocity if the two carts stick
together? - ANSWER--0.0714 m/s
m1v1+m2v2=(m1+m2)vf
, A cart with mass 0.30 kg and velocity 0.20 m/s collided on an air-track with a cart with
mass 0.40 kg and velocity -0.10 m/s. What is the final velocity in m/s of the two carts if
they stick together? - ANSWER-0.029 m/s
m1v1+m2v2=(m1+m2)vf
A mass and spring system has a resonance f0=1.40 Hz with a full-width of f(FW)=0.021
Hz. What is the quality factor Q? - ANSWER-66.67
f(FW)=f0/Q
A sonic ranger measures positions X=0.10 m, 0.15 m, 0.22 m, 0.28 m at times t=0 s,
0.10 s, 0.20 s, and 0.30 s. Find the magnitude of the average velocity between t=0.10 s
and 0.20 s. - ANSWER-0.7 m/s
Deltax/deltat
A student measures the four lowest resonant frequencies of the string as 12 Hz, 25 Hz,
35 Hz, and 50.0 Hz, with node-to-node spacing of 2.0 m, 1.0 m, 0.67 m, and 0.50 m.
Calculate the wave velocity for each of the four different modes. - ANSWER-v1=48 m/s
v2=50 m/s
v3=46.9 m/s
v4=50 m/s
v=wavelength*frequency
A student measures wave speeds of 5 m/s, 7 m/s, 10 m/s, and 15 m/s for tensions of 1
N, 2N, 4 N, and 9 N. Use the spreadsheet to make a log log plot of the wave speed
versus the tension. Also find the slope of the resulting line. - ANSWER-Take log of both
variables. Plot. Add trendline with equation.
Consider a 1.5 m long string with linear mass density of 0.0010 kg/m and a tension of
0.50 N. Find the frequency in Hz of the fundamental mode of the string. - ANSWER-
7.45 Hz
v=sqrt(T/mu)
v=wavelength*frequency
Consider the properties of a string that has a length of 1.0 m and a wave speed of 45
m/s. What is the fundamental frequency of the string? - ANSWER-22.5 Hz
v=wavelength*frequency
Experiment 2: errors
Purpose: - ANSWER-To learn how to estimate uncertainty in measurements, how to do
error propagation, and why it is important to understand the uncertainty in
measurements
Experiment 3: X, V, and A
and Answers Graded A+
A block is measured to have a density p=2.76 g/cm3 with an uncertainty of
deltap=0.030 g/cm3. Find chi-squared when the measured density is compared to the
accepted density p=2.70 g/cm3. - ANSWER-Chi-squared=4
Chi-squared=sum((xi-xtheory)/deltaxi)^2
A block is measured to have mass M=25.3 g and volume V=9.16 cm3 with an
uncertainty of deltaM=0.050 g in the mass and deltaV=0.050 cm3 in the volume. What
is the uncertainty in the density? - ANSWER-0.016 g/cm3
(Deltap/p)^2=(deltaM/M)^2+(deltaV/V)^2
A cart of mass m=0.20 kg rides on an air track that is tilted at an angle 2 degrees from
the horizontal. What is the magnitude of the total force on the cart? - ANSWER-0.068 N
Mass*9.8*sin(theta)
A cart of mass m=0.25 kg rides on an air track that is tilted 3 degrees from the
horizontal. What is the magnitude of the cart's acceleration? - ANSWER-0.51 m/s^2
9.8*sin(theta)
A cart starts at X=0.5 m with an initial velocity of 1 m/s heading up the airtrack.
Assuming that the airtrack is tilted at 0.01 radians, use the spreadsheet to calculate and
plot the position versus time and the velocity versus time of the cart. - ANSWER-
d=d0+v0*t+(a0*t^2)/2
a0=g*sin(theta)
v=vi+a0*t
A cart with mass 0.3 kg and velocity 0.1 m/s collides on an air track with a cart with
mass 0.4 kg and velocity -0.2 m/s. If the final velocity of the first cart is -0.1 m/s after the
collision, what is the velocity of the second cart? - ANSWER--0.05 m/s
mv=mv
A cart with mass 0.30 kg and velocity 0.10 m/s collided on an air-track with a cart with
mass 0.40 kg and velocity -0.20 m/s. What is the final velocity if the two carts stick
together? - ANSWER--0.0714 m/s
m1v1+m2v2=(m1+m2)vf
, A cart with mass 0.30 kg and velocity 0.20 m/s collided on an air-track with a cart with
mass 0.40 kg and velocity -0.10 m/s. What is the final velocity in m/s of the two carts if
they stick together? - ANSWER-0.029 m/s
m1v1+m2v2=(m1+m2)vf
A mass and spring system has a resonance f0=1.40 Hz with a full-width of f(FW)=0.021
Hz. What is the quality factor Q? - ANSWER-66.67
f(FW)=f0/Q
A sonic ranger measures positions X=0.10 m, 0.15 m, 0.22 m, 0.28 m at times t=0 s,
0.10 s, 0.20 s, and 0.30 s. Find the magnitude of the average velocity between t=0.10 s
and 0.20 s. - ANSWER-0.7 m/s
Deltax/deltat
A student measures the four lowest resonant frequencies of the string as 12 Hz, 25 Hz,
35 Hz, and 50.0 Hz, with node-to-node spacing of 2.0 m, 1.0 m, 0.67 m, and 0.50 m.
Calculate the wave velocity for each of the four different modes. - ANSWER-v1=48 m/s
v2=50 m/s
v3=46.9 m/s
v4=50 m/s
v=wavelength*frequency
A student measures wave speeds of 5 m/s, 7 m/s, 10 m/s, and 15 m/s for tensions of 1
N, 2N, 4 N, and 9 N. Use the spreadsheet to make a log log plot of the wave speed
versus the tension. Also find the slope of the resulting line. - ANSWER-Take log of both
variables. Plot. Add trendline with equation.
Consider a 1.5 m long string with linear mass density of 0.0010 kg/m and a tension of
0.50 N. Find the frequency in Hz of the fundamental mode of the string. - ANSWER-
7.45 Hz
v=sqrt(T/mu)
v=wavelength*frequency
Consider the properties of a string that has a length of 1.0 m and a wave speed of 45
m/s. What is the fundamental frequency of the string? - ANSWER-22.5 Hz
v=wavelength*frequency
Experiment 2: errors
Purpose: - ANSWER-To learn how to estimate uncertainty in measurements, how to do
error propagation, and why it is important to understand the uncertainty in
measurements
Experiment 3: X, V, and A
