Case Study and Passage Based Questions for Class 9 Science Chapter 9 Force and Laws of Motion

Case Study/Passage Based Questions:

Question 1:

Read the following and answer any four questions from (i) to (v) given below :

In the figure below the card is flicked with a push. It was observed that the card moves ahead while coin falls in glass.

(i) Give reason for the above observation.
(a) The coin possesses inertia of rest, it resists the change and hence falls in the glass.
(b) The coin possesses inertia of motion; it resists the change and hence falls in the glass.
(c) The coin possesses inertia of rest, it accepts the change and hence falls in the glass.
(d) The coin possesses inertia of rest, it accepts the change and hence falls in the glass.

Answer

Ans. (a) The coin possesses inertia of rest, it resists the change and hence falls in the glass.

---

(ii) Name the law involved in this case.
(a) Newton’s second law of motion.
(b) Newton’s first law of motion.
(c) Newton’s third law of motion.
(d) Law of conservation of energy

Answer

Ans. (b) Newton’s first law of motion.
Explanation: According to first law of motion, everybody tends to resist change of state whether in rest or in when acted by an external force.

---

(iii) If the above coin is replaced by a heavy five-rupee coin, what will be your observation. Give reason.
(a) Heavy coin will possess more inertia so it will not fall in tumbler.
(b) Heavy coin will possess less inertia so it will fall in tumbler.
(c) Heavy coin will possess more inertia so it will fall in tumbler.
(d) Heavy coin will possess less inertia so it will not fall in tumbler.

Answer

Ans. (c) Heavy coin will possess more inertia so it will fall in tumbler.

---

(iv) Name the law which provides the definition of force.
(a) Law of conservation of mass
(b) Newton’s third law.
(c) Newton’s first law
(d) Newton’s second law.

Answer

Ans. (d) Newton’s second law.
Explanation: Formula for measuring force is given by Newton’s 2nd law.

---

(v) State Newton’s first law of motion.
(a) Energy can neither be created nor be destroyed, it can be converted from one form to another, total amount of energy always remains constant.
(b) A body at rest remains at rest or, if in motion, remains in motion at constant velocity unless it is acted upon by an external unbalanced force.
(c) For every action in nature there is an equal and opposite reaction.
(d) The acceleration in an object is directly related to the net force and inversely related to its mass.

Answer

Ans. (b) A body at rest remains at rest or, if in motion, remains in motion at constant velocity unless it is acted upon by an external unbalanced force.

---

Other Chapters: