A body slides down a frictionless incline of angle 30°. What is the acceleration along the plane?

The correct answer is A: 5 m/s². On a frictionless incline: a = g sin θ = 10 × sin(30°) = 10 × 0.5 = 5 m/s²

The maximum possible efficiency of a heat engine operating between 400 K and 500 K is:

The correct answer is B: 20%. Maximum efficiency is Carnot efficiency: η_max = 1 - T_c/T_h = 1 - (400/500) = 1 - 0.8 = 0.2 = 20%.

Two identical gases at the same temperature and pressure occupy different volumes. Which thermodynamic property must be the same for both?

The correct answer is D: Chemical potential per molecule. At same T and P, the chemical potential per molecule is identical. Internal energy and entropy depend on amount (volume), heat capacity depends on mass.

A reversible engine and an irreversible engine operate between the same two temperatures. Which has greater efficiency?

The correct answer is A: Reversible engine. Carnot (reversible) engine has maximum efficiency between any two temperatures. All real irreversible engines are less efficient.

A substance undergoes a phase transition from solid to liquid at constant temperature and pressure. During this process:

The correct answer is C: Entropy increases. Phase transition increases disorder, so entropy increases. Q = TΔS, and since T is constant and Q > 0, ΔS > 0.

Home

Home › Subjects › NEET Physics › Mechanics & Laws of Motion

NEET Physics
Mechanics & Laws of Motion

Physics questions for NEET UG — Mechanics, Thermodynamics, Optics, Modern Physics.

49 Q 2 Topics Take Mock Test

Difficulty: All Easy Medium Hard 41–49 of 49

Topics in NEET Physics

All Mechanics & Laws of Motion 100 Thermodynamics 100

Q.41 Medium Mechanics & Laws of Motion

Two objects A and B have the same mass but A is moving at 10 m/s and B is moving at 5 m/s. If equal forces bring both to rest, which one travels a greater distance?

A A travels greater distance

B B travels greater distance

C Both travel equal distance

D Cannot be determined

Correct Answer: A. A travels greater distance

EXPLANATION

Using v² = u² + 2as, with same deceleration, the object with higher initial velocity (A) travels a greater distance.

Test

Q.42 Medium Mechanics & Laws of Motion

An object of mass 5 kg is suspended by a rope. The rope can withstand a maximum tension of 60 N. If the object is accelerated upward, what is the maximum upward acceleration? (g = 10 m/s²)

A 2 m/s²

B 4 m/s²

C 6 m/s²

D 8 m/s²

Correct Answer: A. 2 m/s²

EXPLANATION

Tension T = m(g + a). Maximum T = 60 N. So 60 = 5(10 + a), which gives 12 = 10 + a, therefore a = 2 m/s².

Test

Q.43 Medium Mechanics & Laws of Motion

A 100 N force is applied on a 10 kg block on a horizontal surface with kinetic friction coefficient μₖ = 0.2. What is the acceleration? (g = 10 m/s²)

A 8 m/s²

B 10 m/s²

C 12 m/s²

D 15 m/s²

Correct Answer: A. 8 m/s²

EXPLANATION

Normal force N = mg = 10 × 10 = 100 N. Friction force f = μₖN = 0.2 × 100 = 20 N. Net force = 100 - 20 = 80 N. Acceleration = 80/10 = 8 m/s².

Test

Q.44 Medium Mechanics & Laws of Motion

A body moving in a circle with constant speed experiences acceleration. This acceleration is directed:

A Tangent to the circle

B Radially outward

C Radially inward

D Vertically downward

Correct Answer: C. Radially inward

EXPLANATION

In uniform circular motion, acceleration (centripetal) is always directed toward the center of the circle (radially inward).

Test

Q.45 Medium Mechanics & Laws of Motion

A 2 kg object moving at 5 m/s collides with a wall and comes to rest in 0.1 seconds. What is the average force exerted by the wall?

A 50 N

B 100 N

C 150 N

D 200 N

Correct Answer: B. 100 N

EXPLANATION

Acceleration a = (v-u)/t = (0-5)/0.1 = -50 m/s². Force F = ma = 2 × (-50) = -100 N. Magnitude = 100 N.

Test

Q.46 Medium Mechanics & Laws of Motion

A 50 kg person stands on a weighing machine in an elevator. When the elevator accelerates downward at 2 m/s², what is the reading on the scale? (g = 10 m/s²)

A 400 N

B 500 N

C 600 N

D 700 N

Correct Answer: A. 400 N

EXPLANATION

Apparent weight = m(g - a) = 50(10 - 2) = 50 × 8 = 400 N.

Test

Q.47 Medium Mechanics & Laws of Motion

A car of mass 1000 kg accelerates uniformly from rest to 20 m/s in 10 seconds on a horizontal road. If friction force is 500 N, what is the driving force?

A 1500 N

B 2000 N

C 2500 N

D 3000 N

Correct Answer: C. 2500 N

EXPLANATION

Acceleration a = (20-0)/10 = 2 m/s². Net force = ma = 1000 × 2 = 2000 N. Driving force = Net force + friction = 2000 + 500 = 2500 N.

Test

Q.48 Medium Mechanics & Laws of Motion

Two blocks of masses m₁ = 3 kg and m₂ = 2 kg are connected by a light string and pulled horizontally with force F = 10 N. What is the tension in the string between them?

A 2 N

B 4 N

C 6 N

D 10 N

Correct Answer: B. 4 N

EXPLANATION

Total acceleration a = F/(m₁+m₂) = 10/5 = 2 m/s². For block m₂, tension T = m₂ × a = 2 × 2 = 4 N.

Test

Q.49 Medium Mechanics & Laws of Motion

A block of mass m slides down a frictionless incline at angle θ. What is the acceleration along the incline?

A g sin θ

B g cos θ

C g tan θ

D g

Correct Answer: A. g sin θ

EXPLANATION

The component of gravitational force along the incline is mg sin θ. Using F = ma, we get a = g sin θ.

Test

1…3 4 5

All Subjects & Topics

Govt. Exams

Entrance Exams

Teacher Exams

Subjects

Quick Links

NEET Physics Mechanics & Laws of Motion

NEET Physics
Mechanics & Laws of Motion