*Force and Motion MCQs* Answer & Explanation at End 🥰 *1. The numerical ratio of displacement to the distance covered is always:* A) Less than one B) Equal to or less than one C) Equal to one D) Equal to or greater than one *2. An insect crawls a distance of 4m north in 10s and then a distance of 3m east in 5s. The average velocity of the insect is:* A) 7/15 ms^-¹ B) 1/5 ms^-¹ C) 1/3 ms^-¹ D) 4/5 ms^-¹ *3. The displacement of a body in 8s starting from rest with an acceleration of 20 ms^-² will be:* A) 64 m B) 64 cm C) 0.064 m D) 640 m *4. Newton's Second law gives the measure of:* A) Acceleration B) Force C) Angular Momentum D) Momentum *5. Which condition must be met for an object's constant velocity?* A) Constant speed only B) Constant direction only C) Both constant speed and constant direction D) Zero acceleration 6. *A car is moving with constant speed but changing direction. What can be said about its acceleration?* a. Zero acceleration b. Constant acceleration c. Changing acceleration d. Uniform acceleration 7.*An object is thrown vertically upwards. At the highest point, its:* a. Acceleration is zero b. Velocity is zero c. Both velocity and acceleration are zero d. Neither velocity nor acceleration is zero *8. If velocity is zero at an instant, then acceleration must be:* a. Zero b. Positive c. Negative d. Any value *9. An object thrown upward has zero velocity at the top. What is its acceleration there?* a. Zero b. Equal to g downward c. Equal to g upward d. Depends on mass *10. Which of these motions is not uniformly accelerated?* a. Free fall b. Circular motion at constant speed c. Rolling down a smooth slope d. Rocket launch in space *🔰 MCQs 1* *Answer key: B* *`Explanation:`* Distance is the total path length, while displacement is the shortest path between two points. Displacement can never exceed distance. If motion is in a straight line with no turning back → ratio = 1. *If there's any deviation or turn → displacement < distance → ratio < 1.* *So, it’s always ≤ 1.* *🔰 MCQs 2* *Answer key: C* *`Explanation:`* Average velocity = total displacement ÷ total time. Here, displacement = 5 m, time = 15 s. → v_avg = 5 ÷ 15 = 1/3 m/s. Even if he walked more than 5 m, we consider only the displacement for velocity. *🔰 MCQs 3* *Answer key: D* *`Explanation:`* Use s = ½ a t² → s = ½ × 20 × 64 = 640 m So, total distance covered is 640 m. *🔰 MCQs 4* *Answer key: B* *`Explanation:`* Newton’s 2nd law: F = ma (force = mass × acceleration). It defines the relation between force and motion. *First law is about inertia.* *Third law is action-reaction.* So, *second law* defines force. *🔰 MCQs 5* *Answer key: C* *`Explanation:`* Constant velocity means both speed and direction stay the same. If either changes, velocity is not constant. So, *motion must be in a straight line at constant speed*. *🔰 MCQs 6* *Answer key: D* *`Explanation:`* Acceleration is a vector—it depends on change in velocity. In circular motion, speed is constant but direction changes. So, *acceleration (centripetal) is always present*. *🔰 MCQs 7* *Answer key: B* *`Explanation:`* At the topmost point of a projectile: Velocity = 0 But gravity still acts → acceleration = 9.8 m/s² downward. So, object has *zero velocity but non-zero acceleration*. *🔰 MCQs 8* *Answer key: D* *`Explanation:`* Zero velocity doesn't mean zero acceleration. Example: At the peak of vertical throw → velocity = 0 But acceleration = g downward. *So, object is still accelerating.* *🔰 MCQs 9* *Answer key: B* *`Explanation:`* Even when vertical velocity becomes zero at the peak of motion, Gravity continues acting downward. So, *acceleration is always 9.8 m/s² downward*. *🔰 MCQs 10* *Answer key: B* *`Explanation:`* In circular motion: Speed is constant But direction keeps changing → velocity changes → acceleration exists. *So acceleration ≠ 0; it's centripetal acceleration.*