2001 WAEC Physics Practical Fix the 100g mass marked P at B, the 80 cm mark of the uniform...

Fix the 100g mass marked P at B, the 80 cm mark of the uniform metre rule, using an adhesive.
Suspend another 100g mass marked Q at A, a distance V = 10.Ocm from the 0 cm mark of the metre rule.
Balance the whole arrangement horizontally on a knife edge as shown in the diagram above.
Measure and record the distance U of K from the 0 cm mark of the metre rule.
Repeat the procedure for five other values of V = 15.0, 20.0, 25.0, 30.0 and 35.0 cm
In each case, measure and record the Corresponding values of U. Tabulate your readings.
Plot a graph of U on the vertical axis against V on the horizontal axis.
determine the:
(1) slope, s, of the graph
(2) intercept c, on the vertical axis.
Evaluate (i) K\(_{1}\) =\(\frac{(1 - 2s)}{s}\) 100:
(ii) K\(_{2}\) = \(\frac{2c}{s}\) - 160
State two precautions taken to ensure an accurate result

(b)i. State two conditions under which a rigid body at rest remains in equilibrium when acted upon by three non-parallel coplanar forces.

ii. Explain how the position of the centre or gravity of a body affects the equilibrium of the body.

Open photo

Table of values

Open photo

Slope = \(\frac{Du}{DN} = \frac{13}{47}\) = 0.28

The intercept (c) on the vertical axis = 44cm

(i) K\(_{1}\) = \(\frac{(1-2s)}{s}\)100 = \(\frac{1-0.56}{0.28}\)100 = 157

(ii) K\(_{2}\) = \(\frac{2c}{s}\) - 160 = \(\frac{2 \times 44}{0.28}\) - 160 = 154.3

Precautions:

(b)i. The conditions under which a rigid body remains in equilibrium when acted upon by three non-parallel coplanar forces are:

The forces must be concurrent (i.e. they must meet at a point.
The resultant of the forces must be equal to zero.
The forces can be represented in magnitude and direction by the sides of a triangle taken in order.
A body is in stable equilibrium if the vertical line through the centre of gravity falls outside the base of support when the body is slightly titled