Science Worksheet (Set 3)
Focus: Chapters 7, 8, and 9
Q1. Answer briefly:
a. A spaceship travels 36,000 km in one hour. Express its speed in km/s.
Speed = Distance / Time = 36000 km / 1 hour = 36000 / 3600 km/s = 10 km/s
b. State the factors on which the time period of a simple pendulum depends.
The time period of a simple pendulum depends on:
– The length of the pendulum.
– The acceleration due to gravity.
– The length of the pendulum.
– The acceleration due to gravity.
c. The distance between two stations is 240 km. A train takes 4 hours to cover this distance. Calculate the speed of the train.
Speed = Distance / Time = 240 km / 4 hours = 60 km/h
d. Do you think osmosis can occur if a membrane is not selectively permeable? Why or why not?
No, osmosis cannot occur if a membrane is not selectively permeable. Osmosis requires a semi-permeable membrane that allows only solvent molecules to pass while restricting solute movement.
e. Name a protein that is responsible for carrying oxygen and carbon dioxide.
Hemoglobin
f. Which of the following parts of a plant has lenticels?
The stem in which secondary growth has taken place.
Q2. Answer the following questions:
a. Read the given case study and answer the questions that follow:
A bakery uses yeast to make bread rise. The yeast cells perform anaerobic respiration (fermentation) when mixed with dough. The bread becomes soft and fluffy. Another product was released but evaporated during the process of fermentation.
i. Name two by-products of fermentation in yeast. Which product evaporated during the process?
The two by-products of fermentation in yeast are ethanol and carbon dioxide. The product that evaporates is ethanol.
ii. Why does the bread rise when yeast performs fermentation?
During fermentation, yeast produces carbon dioxide, which gets trapped in the dough, creating air pockets. This causes the dough to expand and makes the bread rise.
b. A person walks 5 km east and then 5 km west. Explain how the distance traveled is a scalar quantity and the displacement is a vector quantity.
– Distance is a scalar quantity because it only considers the total path covered, which is:
5 km (east) + 5 km (west) = 10 km
– Displacement is a vector quantity because it considers both magnitude and direction. Since the person returns to the starting point, the net displacement is zero.
5 km (east) + 5 km (west) = 10 km
– Displacement is a vector quantity because it considers both magnitude and direction. Since the person returns to the starting point, the net displacement is zero.