Question 1
The vernier calipers shown in figure 1 has a zero error of +0.05cm
What reading is indicated by the instrument
Answer
2.60 + 0.05 = 2.65cm
2.65 – 0.05 = 2.60cm
2.65 – 0.05 = 2.60cm
Question 2
State two factors on which the extension of a wire depends on assuming it obeys Hooke’s Law
Answer
(i) Elastic limit must not be exceeded
(ii) Constant temperature ensured
(ii) Constant temperature ensured
Question 3
Figure 2 show a solid cone which has a uniform density in equilibrium
Determine the weight of the cone
Answer
Clockwise moments = anticlockwise moments
Question 4
A hot air balloon is tethered to the ground on a windless day as shown in figure 3
The envelope of the balloon contains 1200m3 of hot air of density 0.8kg/m3. Mass of the empty balloon is 400kg. Density of the surrounding air is 1.3kg/m3. Calculate the tension in the rope holding the balloon on the ground
Answer
Question 5
A wooden bench and a metal bench are both left in the sun for a long time. Explain why the metal bench feels hotter to touch
Answer
Because metal is a good conductor
Heat is conducted from outer parts to the point touched while wood is a poor conductor
Heat is conducted from outer parts to the point touched while wood is a poor conductor