This quiz works best with JavaScript enabled. Home > Class 9 > Class 9 Science Chapter 9 Force And Laws Of Motion – Quiz 15 🏠 Homepage 📘 Download PDF Books 📕 Premium PDF Books Class 9 Science Chapter 9 Force And Laws Of Motion Quiz 15 (24 MCQs) Quiz Instructions Select an option to see the correct answer instantly. 1. In a rocket, fuel burns at the rate of 1 kg/s. This fuel is ejected from the rocket with a velocity of 60 km/s. This exerts a force on the rocket equal to A) 6000 N. B) 60000 N. C) 60 N. D) 600 N. Show Answer Correct Answer: B) 60000 N. 2. In the equation F = ma, what does 'a' represent? A) Force. B) Mass. C) Acceleration. D) Velocity. Show Answer Correct Answer: C) Acceleration. 3. A person is standing in an elevator. In which situation he finds his weight less than actual when A) The elevator moves downward with constant acceleration. B) The elevator moves upward with constant acceleration. C) The elevator moves upward with uniform velocity. D) The elevator moves downward with uniform velocity. Show Answer Correct Answer: A) The elevator moves downward with constant acceleration. 4. A force produces an acceleration 5 cm/s$^{2}$ when it acts on a body of 20 g. Find the force acting on the body. A) 0.002 N. B) 0.004 N. C) 0.001 N. D) 0.005 N. Show Answer Correct Answer: C) 0.001 N. 5. When the resultant of the forces acting on the body is zero, these are called A) Balanced force. B) Unbalanced force. C) Both. D) None of the above. Show Answer Correct Answer: A) Balanced force. 6. If an action force is a cue ball (white) hitting a billiard ball (various colors) when playing pool, then the reaction force is A) Exerted on the table. B) Not present. C) Exerted by the billiard ball on the cue ball. D) Exerted on all the other billiard balls. Show Answer Correct Answer: D) Exerted on all the other billiard balls. 7. What is the acceleration of an object that takes 20 seconds to change from a speed of 200 meters/second to 300 meters/second? A) 5 m/s squared. B) 5 m/s. C) 100 m/s. D) 100 m/s squared. Show Answer Correct Answer: A) 5 m/s squared. 8. The force of an object, with a certain mass accelerating at a certain rate, can be determined by using the equation below. force = mass x accelerationWhich object would have the greatest force? A) A 5 kg object accelerating at 10 m/s. B) A 5 kg object accelerating at 20 m/s. C) A 20 kg object accelerating at 4 m/s. D) A 20 kg object accelerating at 3 m/s. Show Answer Correct Answer: B) A 5 kg object accelerating at 20 m/s. 9. Which of the following best describes the velocity of an object? A) 30 m/s. B) 30 m East. C) 30 m/s East. D) 30 m/s$^{2}$. Show Answer Correct Answer: C) 30 m/s East. 10. Friction depends on A) The smoothness or roughness of the two surfaces which are not in contact. B) The smoothness or roughness of the two surfaces which are in contact. C) Infinity stones. D) Inertia. Show Answer Correct Answer: B) The smoothness or roughness of the two surfaces which are in contact. 11. Newton's first law of motion says that a moving body should continue to move forever, unless some external forces act on it. But a moving cycle comes to rest after some time if we stop pedaling it. Can you choose the correct reason for the stoppage of cycle?i. Air resistanceii. Gravitational pull of the earthiii. Friction of the road iii. Heat of the environmentChoose the correct option: A) (iii) and (iv). B) (i) and (iii). C) (i) and (ii). D) (ii) and (iii). Show Answer Correct Answer: B) (i) and (iii). 12. The seat belts are provided in the cars so that if the car stops suddenly due to an emergency braking, the persons sitting on the front seats are not thrown forward violently and saved from getting injured. Can you guess the law due to which a person falls in forward direction on the sudden stopping of the car? A) Newton's first law of motion. B) Newton's second law of motion. C) Newton's third law of motion. D) Newton's law of gravitation. Show Answer Correct Answer: A) Newton's first law of motion. 13. Swimming can be explained by A) Newton's law of gravitation. B) First law of motion. C) Second law of motion. D) Third law of motion. Show Answer Correct Answer: D) Third law of motion. 14. Speed is different from velocity because A) Velocity has a direction. B) Speed uses Distance /Time. C) Velocity doesn't include time. D) Velocity doesn't include distance. Show Answer Correct Answer: A) Velocity has a direction. 15. The velocity of a body of mass 20 kg decreases from 20 m/s to 5 m/s in a distance of 100 m. Force on the body is A) -27.5 N. B) -47.5 N. C) -37.5 N. D) -67.5 N. Show Answer Correct Answer: C) -37.5 N. 16. A constant retarding force of 80 N is applied to a body of mass 50 kg which is moving initially with a speed of 20 m/s. What would be the time required by the body to come to rest? A) 12.5 s. B) 15 s. C) 14 s. D) 18 s. Show Answer Correct Answer: A) 12.5 s. 17. Which has more momentum? A) Rolling a bowling ball with a large mass and low velocity. B) Throwing a baseball with a small mass and a high velocity. C) They have the same. D) None of the above. Show Answer Correct Answer: C) They have the same. 18. Newton's first law of motion is also called Galileo's law of: A) Conservation of momentum. B) Inertia. C) Friction. D) Conservation of mass. Show Answer Correct Answer: B) Inertia. 19. A 10-kg brick and a 1-kg book are dropped in a vacuum. The force of gravity on the 10-kg brick is A) 10 times as much as the force on the 1-kg book. B) Zero. C) The same as the force on the 1-kg book. D) None of the above. Show Answer Correct Answer: A) 10 times as much as the force on the 1-kg book. 20. How does acceleration of an object change relation to its mass? It is A) Directly proportional. B) Inversely proportional. C) Acceleration doesn't depend on mass at all. D) Directly to square root. Show Answer Correct Answer: B) Inversely proportional. 21. A hammer of mass 300 g, moving at 40m/s, strikes a nail. The nail stops the hammer in a very short time of 0.02 s. The force of the nail on the hammer is A) 600N. B) 1200N. C) 2000N. D) 2500N. Show Answer Correct Answer: A) 600N. 22. A cricket ball of mass 100 g with a speed of 30 m/s is brought to rest by a player in 0.03 s. What is the change of momentum and average force applied by the player respectively? A) 109 N & 5 Kgm/s. B) 5 Kgm/s &-100 N. C) -3 Kgm/s &-100 N. D) -3 Kgm/s &-90 N. Show Answer Correct Answer: C) -3 Kgm/s &-100 N. 23. How much net force is required to accelerate a 1000 kg car at 4 m/s$^{2}$? A) 250 N. B) 4000 N. C) 0.004 N. D) 400 N. Show Answer Correct Answer: B) 4000 N. 24. A 10 kg mass is dropped from a tall rooftop and accelerates at 9.8 m/s$^{2}$. What is the weight of the dropped object? A) 0 N. B) 9.8 N. C) 98 N. D) 198 N. Show Answer Correct Answer: C) 98 N. ← PreviousRelated QuizzesClass 9 Science Chapter 9 Force And Laws Of Motion Quiz 1Class 9 Science Chapter 9 Force And Laws Of Motion Quiz 2Class 9 Science Chapter 9 Force And Laws Of Motion Quiz 3Class 9 Science Chapter 9 Force And Laws Of Motion Quiz 4Class 9 Science Chapter 9 Force And Laws Of Motion Quiz 5Class 9 Science Chapter 9 Force And Laws Of Motion Quiz 6Class 9 Science Chapter 9 Force And Laws Of Motion Quiz 7Class 9 Science Chapter 9 Force And Laws Of Motion Quiz 8Class 9 Science Chapter 9 Force And Laws Of Motion Quiz 9Class 9 Science Chapter 9 Force And Laws Of Motion Quiz 10 🏠 Back to Homepage 📘 Download PDF Books 📕 Premium PDF Books