## Force and Speed class 9 Question Answer

### 1. What is the speed of the Earth’s rotation considering the Earth as a point relative to the Sun?

Answer:  In this case, the earth’s rotation will be circular motion.

### 2. What is the speed of a rotating object relative to its axis?

Answer:   Rotational speed is the speed of an object rotating about its axis.

### 3. What is the direction of movement? *

Ans:  The direction of motion of the object from its initial position to its final position is considered.

### 4. Which of the objects of mass 5 kg 6 kg falling smoothly from rest will have greater acceleration?

Answer:  Both friends will continue to fall with the same acceleration (gravitational acceleration).

### 5. If the velocity-time graph of a moving object is parallel to the time axis, what is the memory of the object?

Answer:  In this case, the acceleration of the friend is zero.

### 6. Write the velocity-time of two moving objects whose angles are 30° and 60° respectively. Which object has the greater acceleration?*

Answer: In the letter whose inclination is 60°, the charge of its corresponding object is higher.

### 7. Can the velocity-time graph of an object be perpendicular to the time axis?

Answer:  No; Because in that case, the text indicates different velocities of the object at the same time, which is impossible.

### 8. What is the distance traveled by a particle moving in equilibrium with initial velocity u in time t?

Answer:  Resolved distance s= ut – 1/2(at^2)

### 9. u What is the velocity of a particle moving with initial velocity and after traveling this distance?

Answer:  If velocity is deterministic, v^2 = ut + 2as

বা, v = root of (u^2+ 2as)

### 10. Which force makes it difficult to push an object over the ground?

Answer:  The friction between the ground and the object makes it difficult to push an object upwards.

### 11. If the mass of an object falling freely from above decreases gradually, what changes in the acceleration of the object?

Answer:  In this case, the acceleration of the object remains the same; This is the gravitational acceleration.

### 12. What is the change in the total linear momentum of the two objects as a result of the collision between the two objects?

Answer: In this case, if no force is applied from outside, there is no change in the total linear momentum of the two objects.

### 13. What kind of speed is the speed of moving bicycle wheels?

Answer:  The motion of the wheels of a moving bicycle is compound motion.

### 14. What kind of speed is clockwise?

Answer:  Clockwise motion is rotational motion or circular motion.

### 15. What is the motion of a freely falling object?

Answer:   Acceleration is the speed of a freely falling object.

### 16. When the passengers of two moving trains see each other still?

Answer:   When two trains are moving side by side at the same speed, the passengers see each other as stationary.

### 17. What kind of speed is the motion of Nagardola?

Answer:  Oscillator speed is the rotational speed.

### 18. Can the distance traveled by a moving particle be zero?

No, the distance traveled by a moving particle can never be zero.

### 19. Can the emission of moving particles be zero?

Ans:   If a moving particle returns to the point from which it started, then the displacement of the particle is zero.

### 20. Can the ratio of distance traveled and displacement value of a moving particle be less than 1?

Answer:   No, the ratio of distance traveled and displacement value of a moving particle is 1 or greater than 1.

### 21. When is the ratio of the distance traveled and displacement of a moving particle 1?

Answer:  If a particle moves along a straight line, the ratio of the distance covered and the value of displacement is 1.

### 22. When is the ratio of the distance traveled and the displacement value of a moving particle greater than 1?

Answer:  When a particle moves in a curved path, the ratio of the distance covered and the displacement value is greater than 1

### 23. What is the dimensional signal of speed?

Ans:  The speed dimensional signal is  LT-1.

### 24. What is the speed?

Answer:   Velocity is a scalar expression because velocity has value but not direction.

### 27. Can the average velocity of a moving particle be zero?

Answer:  No, the average velocity of a moving particle cannot be zero.

### 28. Can the average velocity of a moving particle be zero?

Answer:  Yes, the average velocity of a moving particle can be zero.

### 29. What is the magnitude of acceleration?

Answer:  The dimensional signal of acceleration is LT-2.

### 30. What is negative acceleration called?

Answer:  Negative acceleration is called deceleration.

31. The emission of a particle at time t, s = 4t + 5t^2. What is the initial velocity of the particle if mass m is unit and time is unit s?

Answer:    Comparing the equation s = 4t + 51^2 with the equation s = ut +1/2(at^2), the initial velocity, u = 4 m/s |

### 32. * Acceleration of a particle at a time, s = 40 + 6t^2 What is the acceleration of the particle if the velocity m is unit and the time is s unit?

Answer: s  = 4t + 61^2 and s= ut+1/2(at^2)—By comparing the two equations, a/2= 6 or, a = 12 m/s^2 |

Hence acceleration of particle = 12 m/s^2

### 34. What is the nature of the displacement-time diagram of a particle in uniform motion?

Answer:   The velocity-time diagram of a particle moving with uniform momentum is a straight line through the origin.

### 35. Which force does not cause an object of constant mass to accelerate?

Answer:  An object of fixed mass does not accelerate under the action of uniform force.

### 36. Which force causes an object of constant mass to accelerate?

Answer:  Acceleration of an object of fixed mass is caused by effective force.

### 37. Which force causes the object to deform?

Answer:  Objects are deformed under the influence of normal force.

### 38. What force can change the static or dynamic state of the object?

Answer: An external force can change the static or dynamic state of an object.

### 39. Write Newton’s first law of motion?

Answer:   A stationary object will remain at rest forever and an object in motion will always move with momentum if no external force is applied.

### 40. What can be the force acting on an object?

Ans:   The force acting on an object can be of two types—

(i)  Internal force o

(ii)  External force.

### 41. The naturalistic definition of force is derived from which of Newton’s laws of motion?

Answer:   Newton’s first law of motion gives the naturalistic definition of force.

### 42. Quantitative definition of force is derived from which of Newton’s laws of motion?

Answer:  Quantitative definition of force is obtained from  Newton’s second law of motion.

### 43. When a bowl full of water is suddenly pushed, in which direction does the water flow—forward or backward?

Answer:  A bowl full of water is pushed suddenly, causing the water to flow backward.

### 44. What is the relationship between Newton and Dyne?

Answer:   1 N = 10^5 dyn

### 45. dyn. g-wt. No What are the absolute units of force in kg-wt?.

Answer:   dyn is the absolute unit of force.

### 46. What is the dimensional signal of linear momentum?

Answer:   The signal in the linear momentum dimension is MLT-11

### 47. Roller push or pull – which is convenient?

Answer:   Pulling the roller is more convenient than pushing it.

### 48. What is the attraction?

Answer:    If two objects come closer to each other as a result of action-reaction, it is called attraction.

### 49. “Action-reaction can establish equality. “Wiki is true or false?

Answer:   The statement is  false .

### 50. The principle of operation of the rocket depends on which principle?

Answer:   The working principle of rocket depends on the principle of conservation of linear momentum.

### 51. What is the instruction object?

Answer:    The object relative to which the position or motion of another object is measured is called the reference object.

### 52. What is the direction of the velocity of a particle traveling in a circular path?

Answer:    The direction of the velocity of a particle moving in a circle is along the tangent to the circle at that point.

### 53. What does the car’s odometer indicate?

Answer:   A car’s odometer indicates the instantaneous speed.

### 54. When do the average velocity and instantaneous velocity of a moving particle become equal?

Answer:   Average velocity and instantaneous velocity of a particle moving with uniform velocity are equal.

### 55. What remains constant at rotational speed?

Answer: The axis ( or rotation ) remains unchanged during  rotational motion

### 56. 1 km/h = how many m/s ?

Answer:    1 km/h = (1000 /60 * 60 ) m/s 5 • m/s =5/18 m/s

### 57. What is the division of the ball into two parts?

Ans:   * Bisection of a force means dividing a force into two specified directions in such a way that the lines of the bisected parts are equal to the given force.

### 58. How many times does the word occur per second in units of acceleration?

Answer:   The unit of acceleration occurs twice per second.

### 59. If a particle moving from rest to equilibrium travels a distance x in 1s, how much distance will it travel in 2s?

Answer:   Particles moving from rest to equilibrium. Distance traveled in time, s ∞ t^2. So in 2s the particle will travel 4x distance.

### 60. What does the slope of the displacement-time diagram indicate?

Answer:   The bottom of the displacement-time diagram indicates the instantaneous velocity.

### 61. What does the slope of the velocity-time diagram indicate?

Answer: The bottom of the velocity-time diagram indicates the instantaneous acceleration.

### 62. What is the nature of the displacement-time diagram of a particle moving in equilibrium?

Ans:    The nature of the displacement-time diagram of a particle moving in parallel is hyperbolic.

### 63. What is the value of a ball if its two right angles are 3N and 4N?

Answer:   Value of force = √3^2 + 4^2 = 5 N

### 64. 13N If one of the two right-angled segments of the ball is 5N, what is the other?

=√13^2-5^2/= √169-25= √144 = 12 N

### 65. What is repulsion?

Answer:    If two objects move away from each other as a result of action-reaction, it is called repulsion.