Question 1
Figure below shows a vernier calipers being used to measure the internal diameter of a test tube
Record the correct reading of the diameter if the instrument has a zero error of – 0.02cm
Answer
Main scale reading = 6.2 cm
The vernier scale mark that coincides with main scale mark is the sixth
Vernier scale reading = 6 x 0.01 = 0.06 cm
Reading = 6.20 + 0.06 = 6.26 cm
Actual reading = 6.26 + 0.02cm = 6.28 cm
The vernier scale mark that coincides with main scale mark is the sixth
Vernier scale reading = 6 x 0.01 = 0.06 cm
Reading = 6.20 + 0.06 = 6.26 cm
Actual reading = 6.26 + 0.02cm = 6.28 cm
Question 2
A uniform wooden bar of length 1M and mass 800g is pivoted at 40cm as shown in figure 2 below.
Calculate the above value of force A if the system is in equilibrium
Answer
Weight of wooden bar = Mg
= 800⁄100 x 10 = 8N
Weight acts through the middle or 50 cm
Taking moments about pivot
Sum of clockwise moments = 8 x 0.1 + 100N x 0.6
System of equilibrium moments = 8 x 0.1 + 100 N x 0.6
= 0.8 + 60 = 60.8 NM
System in equilibrium sum of clockwise moment is equally to sum of anticlockwise moments
= 800⁄100 x 10 = 8N
Weight acts through the middle or 50 cm
Taking moments about pivot
Sum of clockwise moments = 8 x 0.1 + 100N x 0.6
System of equilibrium moments = 8 x 0.1 + 100 N x 0.6
= 0.8 + 60 = 60.8 NM
System in equilibrium sum of clockwise moment is equally to sum of anticlockwise moments
Question 3
In the figure 3, below, air is blown into the tube. Indicate the level of water in the beaker X and Y
Answer
Question 4
In the set up shown in the figure below, water near the top of the boiling tube boils while at the bottom remained cold
Explain this observation
Answer
Water and glass are poor conductors of heat therefore convectional current set up at the point of heating cause the hot liquid to move to the top of the boiling tube and evaporate
Question 5
A bucket full of water is whirled in a vertical circular path of radius 1.6M. Determine the minimum speed required to keep the water intact.(g = 10Nkg-1)
Answer
