Impulse : āĻ āĻāĻŋāĻāĻžāϤ = Formula & When to Use : āϏā§āϤā§ā§° āĻā§°ā§ āĻŦā§āĻ¯ā§ąāĻšāĻžā§°
Impulse : āĻ āĻāĻŋāĻāĻžāϤ : Impulse is the change in momentum of an object. (āĻ āĻāĻŋāĻāĻžāϤ āĻšā§āĻā§ āĻā§āύ⧠āĻŦāϏā§āϤā§ā§° āĻā§°āĻŦā§āĻā§° āĻĒā§°āĻŋāĻŦāϰā§āϤāύāĨ¤) When force acts on an object for some time, velocity and momentum change. (āϝā§āϤāĻŋāϝāĻŧāĻž āĻā§āύ⧠āĻŦāϏā§āϤā§ā§° āĻāĻĒā§°āϤ āĻāĻŋāĻā§ āϏāĻŽāϝāĻŧ āϧ⧰āĻŋ āĻŦāϞ āĻĒā§ā§°āϝāĻŧā§āĻ āĻšāϝāĻŧ, āϤā§āϤāĻŋāϝāĻŧāĻž āĻŦā§āĻ āĻā§°ā§ āĻā§°āĻŦā§āĻ āϏāϞāύāĻŋ āĻšāϝāĻŧāĨ¤)
Formula & When to Use : āϏā§āϤā§ā§° āĻā§°ā§ āĻŦā§āĻ¯ā§ąāĻšāĻžā§°
Formula / āϏā§āϤā§ā§°: Impulse = F × t
- Impulse = Force × Time (āĻ āĻāĻŋāĻāĻžāϤ = āĻŦāϞ × āϏāĻŽāϝāĻŧ)
- Impulse = Change in momentum (āĻ
āĻāĻŋāĻāĻžāϤ = āĻā§°āĻŦā§āĻā§° āĻĒā§°āĻŋāĻŦāϰā§āϤāύ)
1. When force is applied for time (ā§§. āϝā§āϤāĻŋāϝāĻŧāĻž āĻāĻŋāĻā§ āϏāĻŽāϝāĻŧ āϧ⧰āĻŋ āĻŦāϞ āĻĒā§ā§°āϝāĻŧā§āĻ āĻšāϝāĻŧ)
Use impulse formula when force acts for a certain duration.
āϝā§āϤāĻŋāϝāĻŧāĻž āĻā§āύ⧠āϏāĻŽāϝāĻŧ āϧ⧰āĻŋ āĻŦāϞ āĻĒā§ā§°āϝāĻŧā§āĻ āĻšāϝāĻŧ āϤā§āϤāĻŋāϝāĻŧāĻž āĻ
āĻāĻŋāĻāĻžāϤ⧰ āϏā§āϤā§ā§° āĻŦā§āĻ¯ā§ąāĻšāĻžā§° āĻā§°āĻž āĻšāϝāĻŧāĨ¤
2. When time duration is given (⧍. āϝā§āϤāĻŋāϝāĻŧāĻž āϏāĻŽāϝāĻŧ āĻĻāĻŋāϝāĻŧāĻž āĻĨāĻžāĻā§)
If force and time are given, impulse can be calculated. āĻŦāϞ āĻā§°ā§ āϏāĻŽāϝāĻŧ āĻĻāĻŋāϝāĻŧāĻž āĻĨāĻžāĻāĻŋāϞ⧠āĻ āĻāĻŋāĻāĻžāϤ āύāĻŋā§°ā§āĻŖāϝāĻŧ āĻā§°āĻŋāĻŦ āĻĒāĻžā§°āĻŋāĨ¤
3. To find change in momentum (ā§Š. āĻā§°āĻŦā§āĻā§° āĻĒā§°āĻŋāĻŦāϰā§āϤāύ āĻāĻžāύāĻŋāĻŦāϞā§)
Impulse helps to find change in momentum. (āĻ āĻāĻŋāĻāĻžāϤ⧠āĻā§°āĻŦā§āĻā§° āĻĒā§°āĻŋāĻŦāϰā§āϤāύ āĻāĻžāύāĻŋāĻŦāϞ⧠āϏāĻšāĻžāϝāĻŧ āĻā§°ā§āĨ¤)
Important Concep (āĻā§ā§°ā§āϤā§āĻŦāĻĒā§āϰā§āĻŖ āϧāĻžā§°āĻŖāĻž)
- More force → More impulse (āĻ āϧāĻŋāĻ āĻŦāϞ → āĻ āϧāĻŋāĻ āĻ āĻāĻŋāĻāĻžāϤ)
- More time → More impulse (āĻ āϧāĻŋāĻ āϏāĻŽāϝāĻŧ → āĻ āϧāĻŋāĻ āĻ āĻāĻŋāĻāĻžāϤ)
- Force changes velocity (āĻŦāϞ⧠āĻŦā§āĻ āϏāϞāύāĻŋ āĻā§°ā§)
- Velocity change → Momentum change (āĻŦā§āĻ āϏāϞāύāĻŋ → āĻā§°āĻŦā§āĻ āϏāϞāύāĻŋ)
SI Unit / SI āĻāĻāĻ : Impulse unit = N·s = kg·m/s (āĻ āĻāĻŋāĻāĻžāϤ⧰ āĻāĻāĻ = N·s = kg·m/s)
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Impulse MCQ : āĻ āĻāĻŋāĻāĻžāϤ MCQ
1. What is impulse ? āĻ āĻāĻŋāĻāĻžāϤ āĻāĻŋ ?
A) Change in force B) Change in momentum C) Change in mass D) Change in density
Ans: B) Change in momentum
Explanation: Impulse is the change in momentum of an object. āĻ āĻāĻŋāĻāĻžāϤ āĻšā§āĻā§ āĻŦāϏā§āϤā§ā§° āĻā§°āĻŦā§āĻā§° āĻĒā§°āĻŋāĻŦāϰā§āϤāύāĨ¤
2. The formula of impulse is: āĻ āĻāĻŋāĻāĻžāϤ⧰ āϏā§āϤā§ā§° āĻā§āύāĻā§ ?
A) P = mv B) F = ma C) Impulse = F × t D) W = mg
Ans: C) Impulse = F × t
Explanation: Impulse = F × t, Impulse equals force multiplied by time. (āĻ āĻāĻŋāĻāĻžāϤ = āĻŦāϞ × āϏāĻŽāϝāĻŧāĨ¤)
3. Impulse depends on: āĻ āĻāĻŋāĻāĻžāϤ āĻāĻŋāĻšā§° āĻāĻĒā§°āϤ āύāĻŋā§°ā§āĻā§° āĻā§°ā§ ?
A) Mass and speed B) Force and time C) Pressure and heat D) Density and volume
Ans: B) Force and time
Explanation: More force or more time gives more impulse. āĻ āϧāĻŋāĻ āĻŦāϞ āĻŦāĻž āĻ āϧāĻŋāĻ āϏāĻŽāϝāĻŧā§ āĻ āϧāĻŋāĻ āĻ āĻāĻŋāĻāĻžāϤ āĻĻāĻŋāϝāĻŧā§āĨ¤)
4. SI unit of impulse is: āĻ āĻāĻŋāĻāĻžāϤ⧰ SI āĻāĻāĻ āĻāĻŋ ?
A) Joule B) Watt C) Newton-second D) Pascal
Ans: C) Newton-second
Explanation: SI unit of impulse = N·s. (āĻ āĻāĻŋāĻāĻžāϤ⧰ SI āĻāĻāĻ = N·s)
5. Impulse is equal to: āĻ āĻāĻŋāĻāĻžāϤ āĻāĻŋāĻšā§° āϏāĻŽāĻžāύ ?
A) Velocity B) Mass C) Change in momentum D) Acceleration
Ans: C) Change in momentum
Explanation: Impulse and change in momentum are equal. (āĻ āĻāĻŋāĻāĻžāϤ āĻā§°ā§ āĻā§°āĻŦā§āĻā§° āĻĒā§°āĻŋāĻŦāϰā§āϤāύ āϏāĻŽāĻžāύāĨ¤)
6. If time increases, impulse will: āϏāĻŽāϝāĻŧ āĻŦā§āĻĻā§āϧāĻŋ āĻĒāĻžāϞ⧠āĻ āĻāĻŋāĻāĻžāϤ -
A) Decrease B) Increase C) Become zero D) Remain same
Ans: B) Increase
Explanation: Impulse is directly proportional to time. (āĻ āĻāĻŋāĻāĻžāϤ āϏāĻŽāϝāĻŧā§° āϏā§āϤ⧠āϏāĻŽāĻžāύā§āĻĒāĻžāϤāĻŋāĻāĨ¤)
7. A large force acting for short time produces: (āĻ āϞā§āĻĒ āϏāĻŽāϝāĻŧā§° āĻŦāĻžāĻŦā§ āĻŦā§āĻšā§ āĻŦāϞ⧠āĻāĻŋ āĻā§āĻĒāύā§āύ āĻā§°ā§ ?)
A) Small impulse B) Large impulse C) Zero impulse D) Constant impulse
Ans: B) Large impulse
Explanation: Large force can produce large impulse even in short time. (āĻŦā§āĻšā§ āĻŦāϞ⧠āĻāĻŽ āϏāĻŽāϝāĻŧāϤ⧠āĻ āϧāĻŋāĻ āĻ āĻāĻŋāĻāĻžāϤ āĻā§āĻĒāύā§āύ āĻā§°āĻŋāĻŦ āĻĒāĻžā§°ā§āĨ¤)
8. Catching a ball with soft hands increases: (āύāϰāĻŽ āĻšāĻžāϤā§ā§°ā§ āĻŦāϞ āϧ⧰āĻŋāϞ⧠āĻāĻŋ āĻŦā§āĻĻā§āϧāĻŋ āĻĒāĻžāϝāĻŧ ?)
A) Force B) Mass C) Time of contact D) Speed
Ans: C) Time of contact
Explanation: Soft hands increase contact time and reduce force. (āύāϰāĻŽ āĻšāĻžāϤ⧠āϏāĻāϏā§āĻĒāϰā§āĻļā§° āϏāĻŽāϝāĻŧ āĻŦā§āĻĻā§āϧāĻŋ āĻā§°ā§ āĻā§°ā§ āĻŦāϞ āĻāĻŽāĻžāϝāĻŧāĨ¤)
9. Which quantity changes due to impulse ? āĻ āĻāĻŋāĻāĻžāϤ⧰ āĻŦāĻžāĻŦā§ āĻā§āύ ā§°āĻžāĻļāĻŋ āϏāϞāύāĻŋ āĻšāϝāĻŧ ?
A) Density B) Volume C) Momentum D) Shape
Ans: C) Momentum
Explanation: Impulse changes momentum. (āĻ āĻāĻŋāĻāĻžāϤ⧠āĻā§°āĻŦā§āĻ āϏāϞāύāĻŋ āĻā§°ā§āĨ¤)
10. Find impulse when force = 8 N and time = 2 s. (āĻŦāϞ = 8 N āĻā§°ā§ āϏāĻŽāϝāĻŧ = 2 s āĻšāϞ⧠āĻ āĻāĻŋāĻāĻžāϤ āύāĻŋā§°ā§āĻŖāϝāĻŧ āĻā§°āĻžāĨ¤)
A) 10 N·s B) 12 N·s C) 16 N·s D) 18 N·s
Ans: C) 16 N·s
Explanation: Impulse(āĻ āĻāĻŋāĻāĻžāϤ) = F × t = 8 × 2 = 16 N·s
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2 Marks Questions (PYQ) : ⧍ āύāĻŽā§āĻŦā§°ā§° āĻĒā§āϰāĻļā§āύ (PYQ)
1. Define impulse. āĻ āĻāĻŋāĻāĻžāϤ⧰ āϏāĻāĻā§āĻāĻž āϞāĻŋāĻāĻžāĨ¤
Ans: Impulse is the change in momentum of an object. (āĻ āĻāĻŋāĻāĻžāϤ āĻšā§āĻā§ āĻā§āύ⧠āĻŦāϏā§āϤā§ā§° āĻā§°āĻŦā§āĻā§° āĻĒā§°āĻŋāĻŦāϰā§āϤāύāĨ¤)
2. Write the formula of impulse. āĻ āĻāĻŋāĻāĻžāϤ⧰ āϏā§āϤā§ā§° āϞāĻŋāĻāĻžāĨ¤
Ans: Impulse = F×t {Impulse = Force × Time (āĻ āĻāĻŋāĻāĻžāϤ = āĻŦāϞ × āϏāĻŽāϝāĻŧ)}
3. Write the SI unit of impulse. āĻ āĻāĻŋāĻāĻžāϤ⧰ SI āĻāĻāĻ āϞāĻŋāĻāĻžāĨ¤
Ans: SI unit of impulse = Newton-second (N·s) (āĻ āĻāĻŋāĻāĻžāϤ⧰ SI āĻāĻāĻ = āύāĻŋāĻāĻāύ-āĻā§āĻā§āĻŖā§āĻĄ (N·s))
4. On which factors does impulse depend ? āĻ āĻāĻŋāĻāĻžāϤ āĻāĻŋāĻšā§° āĻāĻĒā§°āϤ āύāĻŋā§°ā§āĻā§° āĻā§°ā§ ?
Ans: Impulse depends on force and time. (āĻ āĻāĻŋāĻāĻžāϤ āĻŦāϞ āĻā§°ā§ āϏāĻŽāϝāĻŧā§° āĻāĻĒā§°āϤ āύāĻŋā§°ā§āĻā§° āĻā§°ā§āĨ¤)
5. What happens to impulse when force increases ? āĻŦāϞ āĻŦā§āĻĻā§āϧāĻŋ āĻĒāĻžāϞ⧠āĻ āĻāĻŋāĻāĻžāϤ⧰ āĻāĻŋ āĻšāϝāĻŧ ?
Ans: Impulse increases with increase in force. (āĻŦāϞ āĻŦā§āĻĻā§āϧāĻŋ āĻĒāĻžāϞ⧠āĻ āĻāĻŋāĻāĻžāϤ⧠āĻŦā§āĻĻā§āϧāĻŋ āĻĒāĻžāϝāĻŧāĨ¤)
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5 Marks Questions (PYQ) : ā§Ģ āύāĻŽā§āĻŦā§°ā§° āĻĒā§āϰāĻļā§āύ (PYQ)
1. Explain impulse with formula and SI unit. āĻ āĻāĻŋāĻāĻžāϤ āϏā§āϤā§ā§° āĻā§°ā§ SI āĻāĻāĻāϏāĻš āĻŦā§āϝāĻžāĻā§āϝāĻž āĻā§°āĻžāĨ¤
Ans: Impulse is the change in momentum of an object. When a force acts on a body for a certain time, the momentum changes. (āĻ āĻāĻŋāĻāĻžāϤ āĻšā§āĻā§ āĻŦāϏā§āϤā§ā§° āĻā§°āĻŦā§āĻā§° āĻĒā§°āĻŋāĻŦāϰā§āϤāύāĨ¤ āĻāĻŋāĻā§ āϏāĻŽāϝāĻŧ āϧ⧰āĻŋ āĻŦāϞ āĻĒā§ā§°āϝāĻŧā§āĻ āĻā§°āĻŋāϞ⧠āĻā§°āĻŦā§āĻ āϏāϞāύāĻŋ āĻšāϝāĻŧāĨ¤)
Impulse = F × t
Where, F = Force , t = Time
2. Calculate impulse when a force of 12 N acts for 4 s. (12 N āĻŦāϞ⧠4 s āϏāĻŽāϝāĻŧ āϧ⧰āĻŋ āĻā§āϰāĻŋāϝāĻŧāĻž āĻā§°āĻŋāϞ⧠āĻ āĻāĻŋāĻāĻžāϤ āύāĻŋā§°ā§āĻŖāϝāĻŧ āĻā§°āĻžāĨ¤)
Ans:
Given / āĻĻāĻŋāϝāĻŧāĻž āĻāĻā§: Force = 12 N, Time = 4 s
Impulse = F × t = 12 × 4 = 48 N·s
Impulse = 48 N·s.
3. Explain relation between impulse and momentum. (āĻ āĻāĻŋāĻāĻžāϤ āĻā§°ā§ āĻā§°āĻŦā§āĻā§° āϏāĻŽā§āĻĒāϰā§āĻ āĻŦā§āϝāĻžāĻā§āϝāĻž āĻā§°āĻžāĨ¤)
Ans: Impulse is equal to the change in momentum of an object. When force acts for some time, momentum changes. āĻ āĻāĻŋāĻāĻžāϤ āĻŦāϏā§āϤā§ā§° āĻā§°āĻŦā§āĻā§° āĻĒā§°āĻŋāĻŦāϰā§āϤāύ⧰ āϏāĻŽāĻžāύāĨ¤ āĻāĻŋāĻā§ āϏāĻŽāϝāĻŧ āϧ⧰āĻŋ āĻŦāϞ āĻĒā§ā§°āϝāĻŧā§āĻā§ āĻā§°āĻŦā§āĻ āϏāϞāύāĻŋ āĻā§°ā§āĨ¤
4. Why do airbags reduce injury during accidents ? āĻĻā§ā§°ā§āĻāĻāύāĻžāϤ āĻāϝāĻŧāĻžā§°āĻŦā§āĻā§ āĻāĻāĻžāϤ āĻāĻŋāϝāĻŧ āĻāĻŽāĻžāϝāĻŧ ?
Ans: Airbags increase the time of contact during collision. Increased time reduces force and injury. āĻāϝāĻŧāĻžā§°āĻŦā§āĻā§ āϏāĻāĻāϰā§āώ⧰ āϏāĻŽāϝāĻŧ āĻŦā§āĻĻā§āϧāĻŋ āĻā§°ā§āĨ¤ āϏāĻŽāϝāĻŧ āĻŦā§āĻĻā§āϧāĻŋ āĻĒāĻžāϞ⧠āĻŦāϞ āĻāĻŽā§ āĻā§°ā§ āĻāĻāĻžāϤ⧠āĻāĻŽ āĻšāϝāĻŧāĨ¤
5. A force of 20 N acts on a body for 3 s. Find the impulse. (20 N āĻŦāϞ⧠3 s āϏāĻŽāϝāĻŧ āϧ⧰āĻŋ āĻŦāϏā§āϤā§ā§° āĻāĻĒā§°āϤ āĻā§āϰāĻŋāϝāĻŧāĻž āĻā§°āĻŋāĻā§āĨ¤ āĻ āĻāĻŋāĻāĻžāϤ āύāĻŋā§°ā§āĻŖāϝāĻŧ āĻā§°āĻžāĨ¤)
Ans:
Given / āĻĻāĻŋāϝāĻŧāĻž āĻāĻā§: Force = 20 N, Time = 3 s
Impulse = F × t = 20 × 3 = 60 N·s
Therefore, impulse = 60 N·s.