NEET Physics 2

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?

Accepted Answer

v√2

Answer

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:

Accepted Answer

2k

Answer

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?

Accepted Answer

Always zero

Answer

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?

Accepted Answer

2.45 m/s²

Answer

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:

Accepted Answer

[ML⁻¹T⁻¹]

Answer

From Newton's law of viscosity F = ηA(dv/dx), solving for η gives dimensions [ML⁻¹T⁻¹].

NEET - National Eligibility cum Entrance Test Practice Test