To determine the forces acting in the tie and the jib of a simple jib crane

To determine the forces acting in the tie and the jib of a simple jib crane

Apparatus

Jib crane apparatus

Procedure

Setup the apparatus as described above. Tied a spring to the point P, which is in equilibrium under the action of three forces whose direction were shown by the sides of ∆PQR this was so because the king post was arranged to be vertical to give the direction of W. because the sides of the   ∆PQR and draw it to the scale to give the structural diagram PQR.

Along R mark of the length L was to represent the load W on a convenient scale. From sides of that ∆. Found the magnitude of the forces in the jib and tie. As we also knowing the arrow heads of the load W. Plotted the arrow head from PQ and LM nad the forces was in state tension or compression. Compared the experimental results with calculated.

After that pass a spring over the pulley at P, fixed it to point T on the king post and applied a load W at other end. There were now four forces acting at P, two of which were known the tensions PT being W. I drew structure diagrame then polygon of the forces TL, MN and complete the results

Observations and calculations

Load W lbs	Forces in Tie Extension or compression		Forces in Tie Extension or compression		Member Readings
	By Exp	By Diag.	By Exp	By Diag.	PQ	PR	QR

Calculation

	Q
							Scale QT=6.70 inch DQ=28.7 inch PR=35.4  inch QR=27.0 inch RT=27.7  inch TR=20.3  inch Weight:- 1lb=1cm
	T
	L
					P
	R