Three Blocks#

Three blocks with masses \(m_A = \) 1.1 \(\rm{kg}\), \(m_B = \) 2.2 \(\rm{kg}\), and \(m_C = \) 4.4 \(\rm{kg}\) are lined up in a row on a frictionless table. All three blocks are pushed forward by a force applied to block \(A\) as shown in the figure (\(F\_\text{on A} = F =\) 31 \(\rm{N}\)). We would like to determine the force block \(B\) exerts on blocks \(A\) and \(C\).

Three blocks of increasing height labelled A, B, and C are lined up in a row. A force F is applied to block A, the smallest block. The blocks are placed in the first quadrant of a cartesian plane.

Part 1#

Draw a closed line around each of the three systems of interest (on the following figure) and show the environment, i.e., objects outside of the system that affect or exert forces on the system. Upload your file as a PDF named “systems.pdf”.

Figure showing three identical copies of the image shown in the main question text.

Answer Section#

File upload box will be shown here.

Part 2#

What information is known?

Answer Section#

Select all the choices that apply.

Note: You will be awarded full marks only if you select all the correct choices and none of the incorrect choices. Choosing incorrect choices as well as not choosing correct choices will result in deductions.

  • \(F_{\text{on A}}\)

  • \(m_A\)

  • \(m_C\)

  • \(m_B\)

  • \(F_{\text{B on A}}\)

  • \(F_{\text{B on C}}\)

Part 3#

What are the unknowns?

Answer Section#

Select all the choices that apply.

Note: You will be awarded full marks only if you select all the correct choices and none of the incorrect choices. Choosing incorrect choices as well as not choosing correct choices will result in deductions.

  • \(F_{\text{B on A}}\)

  • \(F_{\text{B on C}}\)

  • \(F_{\text{on A}}\)

  • \(m_A\)

  • \(m_C\)

  • \(m_B\)

Part 4#

Draw a free body diagram for each individual masse and connect the action/reaction force pairs with dashed lines. Also remember to show the net forces. Upload your file as a PDF named “fbd.pdf”.

Figure showing three cartesian planes - one for each mass.

Answer Section#

File upload box will be shown here.

Part 5#

Apply Newton’s 2nd law to block \(A\) along the x-axis.

Let \(a\) be the acceleration.

Use the following table as a reference for each variable. Note that it may not be necessary to use every variable.

For \(\quad \quad\)

Use

\(F\_{\text{on A}}\)

F_a

\(F\_{\text{B on A}}\)

F_ba

\(F\_{\text{A on B}}\)

F_ab

\(F\_{\text{C on B}}\)

F_cb

\(F\_{\text{B on C}}\)

F_bc

Answer Section#

Part 6#

Apply Newton’s 2nd law to block \(B\) along the x-axis.

Let \(a\) be the acceleration.

Use the following table as a reference for each variable. Note that it may not be necessary to use every variable.

For \(\quad \quad\)

Use

\(F\_{\text{on A}}\)

F_a

\(F\_{\text{B on A}}\)

F_ba

\(F\_{\text{A on B}}\)

F_ab

\(F\_{\text{C on B}}\)

F_cb

\(F\_{\text{B on C}}\)

F_bc

Answer Section#

Part 7#

Apply Newton’s 2nd law to block \(C\) along the x-axis.

Let \(a\) be the acceleration.

Use the following table as a reference for each variable. Note that it may not be necessary to use every variable.

For \(\quad \quad\)

Use

\(F\_{\text{on A}}\)

F_a

\(F\_{\text{B on A}}\)

F_ba

\(F\_{\text{A on B}}\)

F_ab

\(F\_{\text{C on B}}\)

F_cb

\(F\_{\text{B on C}}\)

F_bc

Answer Section#

Part 8#

Apply Newton’s 2nd law and calculate the acceleration.

Answer Section#

Please enter in a numeric value in \(\rm{m/s^2}\).

Part 9#

Using the acceleration obtained in Part 8, determine the force exerted by block \(B\) on block \(A\), \(F\_{\text{B on A}}\).

Answer Section#

Please enter in a numeric value in \(\rm{N}\).

Part 10#

Using the acceleration obtained in Part 8, determine the force exerted by block \(B\) on block \(C\), \(F\_{\text{B on C}}\).

Answer Section#

Please enter in a numeric value in \(\rm{N}\).

Attribution#

Problem is licensed under the CC-BY-NC-SA 4.0 license.
The Creative Commons 4.0 license requiring attribution-BY, non-commercial-NC, and share-alike-SA license.