NEET Physics 2 — Questions and Answers
Question 1: A body moves in a circle of radius R with uniform speed v. What is the magnitude of the change in velocity when the body completes a quarter circle?
- v√2 (Correct answer)
- 2v
- v/√2
- 0
Correct answer: v√2
When the body completes a quarter circle, the angle between initial and final velocity vectors is 90°, so |Δv| = √(v²+v²) = v√2.
Question 2: A spring of spring constant k is cut into two equal halves. The spring constant of each half is:
- 2k (Correct answer)
- k/2
- k
- 4k
Correct answer: 2k
Spring constant is inversely proportional to length, so cutting the spring in half doubles the spring constant of each piece to 2k.
Question 3: Which of the following correctly describes the work done by a conservative force in a closed path?
- Always zero (Correct answer)
- Always positive
- Always negative
- Depends on the path
Correct answer: Always zero
A defining property of conservative forces is that the work done along any closed path is always zero.
Question 4: Two blocks of masses 3 kg and 5 kg are connected by a string over a frictionless pulley. What is the acceleration of the system?
- 2.45 m/s² (Correct answer)
- 4.9 m/s²
- 9.8 m/s²
- 1.22 m/s²
Correct answer: 2.45 m/s²
For an Atwood machine, a = (m₂−m₁)g/(m₁+m₂) = (5−3)×9.8/(3+5) = 2.45 m/s².
Question 5: The dimensional formula for coefficient of viscosity (η) is:
- [ML⁻¹T⁻¹] (Correct answer)
- [MLT⁻¹]
- [ML⁻¹T⁻²]
- [M⁰L⁰T⁰]
Correct answer: [ML⁻¹T⁻¹]
From Newton's law of viscosity F = ηA(dv/dx), solving for η gives dimensions [ML⁻¹T⁻¹].
Question 6: A particle undergoes simple harmonic motion with amplitude A and angular frequency ω. The maximum acceleration of the particle is:
- ω²A (Correct answer)
- ωA
- ω²A²
- 2ωA
Correct answer: ω²A
The acceleration in SHM is a = −ω²x, which is maximum when displacement x equals amplitude A, giving |a_max| = ω²A.
Question 7: What happens to the time period of a simple pendulum when it is taken from the Earth's surface to the Moon's surface?
- Increases (Correct answer)
- Decreases
- Remains the same
- Becomes zero
Correct answer: Increases
The Moon's gravitational acceleration is about 1/6 of Earth's, so T = 2π√(L/g) increases since g decreases.
NEET Physics 2
A body moves in a circle of radius R with uniform speed v.
What is the magnitude of the change in velocity when the body completes a quarter circle?