Question 1
Figure 1 below shows a micrometer screw gauge being used to measure the diameter of a metal rod. The thimble scale has 50 divisions
Find the diameter of the metal rod
Answer
16.21mm
Question 2
A man of mass 72kg jumps from a small boat on to the lake shore with a forward velocity of 9.0ms-1. If the mass of the boat is 216kg, calculate the initial backward velocity of the boat.
Answer
Momentum is conserved momentum before = momentum after
72 x 9 = 216 x 4
= 3.0m/s
72 x 9 = 216 x 4
= 3.0m/s
Question 3
Explain briefly how the temperature in a green house is kept higher than outside
Answer
Roofing materials allows radiations to penetrate into the greenhouse but not out. Higher concentration of carbon dioxide inside the greenhouse helps to retain higher temperature by trapping/ insulating the heat.
Question 4
The diagram shown in figure 2 below is an arrangement of three pulley wheels used to help in lifting loads. Use it to answer questions 4 and 5.
Complete the diagram to show how the rope goes round the wheels, position of the load and the effort.
Answer
Question 5
Write down the velocity ratio (VR) of the system
Answer
V.R = 3