Science Worksheet (Set 4)
Q1. Answer the following questions:
a. Plot a distance-time graph of the tip of the second hand of a clock by selecting 4 points on the x-axis and y-axis respectively.
The circumference of the circle traced by the second-hand clock is 64 cm.
The circumference of the circle traced by the second-hand clock is 64 cm.
b. Critique the statement: “A heavier pendulum bob swings faster than a lighter bob.” Provide reasons for your evaluation.
The statement is incorrect. The time period of a simple pendulum depends only on the length of the string and the acceleration due to gravity, not the mass of the bob. Therefore, both a heavier and a lighter bob will swing at the same rate if the length remains unchanged.
c. Name the organelle where most of the aerobic respiration occurs. Also, write the equation of aerobic respiration in animals.
The organelle where aerobic respiration occurs: Mitochondria
Aerobic respiration equation:
Glucose + Oxygen → Carbon dioxide + Water + Energy
C6H12O6 + 6O2 → 6CO2 + 6H2O + ATP
Aerobic respiration equation:
Glucose + Oxygen → Carbon dioxide + Water + Energy
C6H12O6 + 6O2 → 6CO2 + 6H2O + ATP
d. Why do earthworms crawl out to the surface during the rainy season?
Earthworms breathe through their skin, which requires moisture. During heavy rain, the soil becomes waterlogged, reducing the oxygen content. To avoid suffocation, earthworms crawl out to the surface.
e. Riya was running a race at her school sports day. Her heart pumped harder, and she could feel her pulse beating faster. As she ran, her muscles needed more oxygen to keep up with the energy demand. This oxygen was delivered through her blood vessels.
i. Explain why Riya’s pulse increased during the race.
Riya’s muscles required more oxygen during the race. To meet this demand, her heart pumped faster, increasing blood circulation and, consequently, her pulse rate.
ii. If Riya injured her leg and it started bleeding, which type of blood vessel is likely damaged if the blood flows out in spurts? Why?
If blood flows out in spurts, it indicates an artery is damaged. Arteries carry oxygen-rich blood under high pressure from the heart, causing blood to spurt in rhythmic pulses.
Riya’s muscles required more oxygen during the race. To meet this demand, her heart pumped faster, increasing blood circulation and, consequently, her pulse rate.
ii. If Riya injured her leg and it started bleeding, which type of blood vessel is likely damaged if the blood flows out in spurts? Why?
If blood flows out in spurts, it indicates an artery is damaged. Arteries carry oxygen-rich blood under high pressure from the heart, causing blood to spurt in rhythmic pulses.
f. If a person drinks a lot of water, how will their urine output change? Why?
If a person drinks a lot of water, their urine output will increase. This is because the kidneys regulate the body’s water balance by removing excess water through urine to maintain homeostasis.
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