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Force and Laws of Motion - Class 9 Exercises Force and Laws of Motion - Class 9 Exercises 1. An object experiences a net zero external unbalanced force. Is it possible for the object to be travelling with a non-zero velocity? If yes, state the conditions that must be placed on the object. Answer: Yes, if the object is moving with constant velocity in a straight line without any unbalanced force acting on it, it will continue moving with that velocity as per Newton's First Law. 2. When a carpet is beaten with a stick, dust comes out of it. Explain. Answer: The carpet moves when beaten, but the dust tends to remain at rest due to inertia and separates out from the carpet. 3. Why is it advised to tie any luggage kept on the roof of a bus with a rope? Answer: To prevent the luggage from moving forward and falling off due to inertia if the bus stops suddenly. 4. A batsman hits a cricket ball which then...

Physics Exercises - Force and Motion Exercises 1. An object experiences a net zero external unbalanced force. Is it possible for the object to be travelling with a non-zero velocity? If yes, state the conditions that must be placed on the object. Answer: Yes, it is possible. If an object is moving with a constant velocity in a straight line , the net external unbalanced force on it is zero. For this to happen, no external unbalanced force should act on the object. 2. When a carpet is beaten with a stick, dust comes out of it. Explain. Answer: When the carpet is beaten, it moves suddenly but the dust particles remain at rest due to inertia , so they separate from the carpet and fall down. 3. Why is it advised to tie any luggage ...

Cell Biology Questions and Answers Cell Biology Questions and Answers 1. Make a comparison and write down ways in which plant cells are different from animal cells. Plant cells have a cell wall, chloroplasts, and a large vacuole. Animal cells do not have a cell wall and chloroplasts and have small vacuoles. Plant cells can make their own food, but animal cells cannot. Plant cells are mostly rectangular, while animal cells are mostly round. 2. How is a prokaryotic cell different from a eukaryotic cell? Prokaryotic cells do not have a true nucleus, while eukaryotic cells have a proper nucleus with a membrane. Prokaryotic cells are smaller and simpler, while eukaryotic cells are larger and complex. Bacteria are prokaryotic, while plants and animals have eukaryotic cells with membrane-bound organelles. 3. What would happen if the plasma membrane ruptures or breaks down? ...

Class 9 Science: Motion - Exercises with Answers Class 9 Science Chapter: Motion - Exercises with Easy Answers Here are the detailed and simple explanations for your exercise questions from the chapter Motion to help you revise effectively. 1. An athlete completes one round of a circular track of diameter 200 m in 40 s. What will be the distance covered and the displacement at the end of 2 minutes 20 s? Answer: Diameter = 200 m, so the circumference = π × 200 = 628 m (approx). Total time = 140 s. Number of rounds = 140 / 40 = 3.5 rounds. Distance covered = 3.5 × 628 = 2198 m (approx). Displacement after 3.5 rounds will be the diameter of the circle (since 0.5 round means opposite side) = 200 m. 2. Joseph jogs from one end A to the other end B of a straight 300 m road in 2 min 30 s and then turns around and jogs 100 m back to point C in another 1 min. What are Joseph's average speeds and velocities in jogging (a) from A to B and (b) from A to C? Answer: (a)...

Motion Class – 9th Standard Mode Motion Class – 9th Standard Mode An athlete completes one round of a circular track of diameter 200 m in 40 s. What will be the distance covered and the displacement at the end of 2 minutes 20 s? Distance per lap = π × 200 m ≃ 628.3 m Total time = 2 min 20 s = 140 s ⇒ laps = 140 ÷ 40 = 3.5 Total distance = 3.5 × 628.3 ≃ 2199.1 m Displacement = straight‐line from start to end. After 3½ laps you’re opposite the start ⇒ 200 m Joseph jogs from A to B (300 m) in 2 min 30 s, then 100 m back to C in 1 min. Find average speed & velocity: a) A→B b) A→C a) A→B Distance = 300 m; Time = 150 s Speed = 300 ÷ 150 = 2.0 m/s Velocity = 300 ÷ 150 = 2.0 m/s b) A→C Total dista...