JAMB Physics Past Questions & Answers - Page 368

Being a uniform rod, the height W should be acting at the mid point 25cm mark.
∴ Taking moment about the fulcrum, F,
200 x 10 = W x 10 + 40 x 30
2000 = 10W + 1200
=> 10W = 2000 - 1200
= 800
w = 800/10 = 80N

The ball has its fastest speed at its equilibrium position when its displacement X = 0, which is at X. At this point, the bob has maximum velocity and maximum kinetic energy.

Resolution of force:
Total vertical upward force:
= 3√3 + 10 cos 60^o
= 3√3 + 5.
Total downward force
= 6 cos 30^o
= 6 x √(³/₂) = 3√3
Total horizontal forces towards right;
= 3N + cos 30^o
= 3N + 10 x √(³/₂)
= 3N + 5√3
Total horizontal forces towards left:
= 6 cos 60^o
= 6 x 0.5
= 3.0N
Summary:
Vertical resultant forces upward:
= 3√3 + 5 - 3√3
= 5N
Horizontal resultant forces towards right:
= 3N + 5√3 - 3√3
= 5N
Horizontal resultant force towards right
= 3N + 5√3 - 3N
= 5√3N

∴ R² = 5² + (5√3)²
= 25 + 25 x 3
= 100
∴ R = √100
= 10N

A good thermometric liquid should not have a high thermal capacity so that the themperetue of the body being measured will not be affected
∴ II, III and IV are qualities of a good thermometer

Young modules = \( \frac{\text{Tensile stress}}{\text{Tensile strain}}\)

= \( 1.1 \times 10^11 = \frac{7.7 \times 10^7}{\text{Tensile Strain}} \)

∴ Tensile strain = \( \frac{7.7 \times 10^7}{1.1 \times 10^11} \)

= \( 7.0 \times 10^{7-11}
= 7.0 \times 10^{-4} \)