JEE Main · Physics ↓ Falling

Laws of Motion appeared 34 times across 3 years — 3.9% of Physics. This question is from Motion on Inclined Plane.

Year 2026 2025 2024 Total
Questions 9 10 15 34

A block is sliding down on an inclined plane of slope θ and at an instant t = 0 this block is given an upward momentum so that it starts moving up on the inclined surface with velocity u . The distance (S) travelled by the block before its velocity become zero, is ____. (g = gravitational acceleration)

Solution & Explanation

Related Formula

v² = u² + 2as

Core Logic

Motion on Inclined Plane diagram for Q28 - JEE Main 2026 Evening
Motion on Inclined Plane diagram for Q28 - JEE Main 2026 Evening

Since the surface is frictionless (implied as no friction coefficient is given), the only force along the incline opposing the upward motion is the component of gravity, mg θ.

Acceleration a = -g θ.

Step 1: Apply Kinematic Equation

Using the third equation of motion: V² = U² + 2as

Set final velocity V = 0:

0 = u² - 2(g θ) S S = (u²)/(2g θ)
Pattern Recognition

For upward motion on a smooth incline, deceleration is purely g θ. The stopping distance is always u² / 2a.

Chapter Mix

Class 11 Physics: Laws of Motion Class 11 Physics: Kinematics

Reference Study Guides

More Laws of Motion Previous-Year Questions — Page 5

Q37 jee_main_2024_01_february_morning Circular Motion
A ball of mass 0.5~kg is attached to a string of length 50~cm. The ball is rotated on a horizontal circular path about its vertical axis. The maximum tension that the string can bear is 400~N. The maximum possible value of angular velocity of the ball in rad/s is:
  • A. 1600
  • B. 40
  • C. 1000
  • D. 20

Solution

Related Formula

Centripetal force configuration for simplified horizontal rotation layout:

T = mω² l

Core Logic

Given values: m = 0.5~kg, l = 50~cm = 0.5~m, Tmax = 400~N.

Equating max tension to centripetal requirement:

400 = 0.5 × ω² × 0.5
Step 1: Compute Angular Velocity
400 = 0.25 ω² ω² = (400)/(0.25) = 1600 ω = √(1600) = 40~rad/s
Pattern Recognition

Ensure units are metric (50~cm → 0.5~m). Direct mapping to horizontal string projection metrics.

Chapter Mix

Class 11 Physics: Laws of Motion

Q36 jee_main_2024_29_january_evening Circular Motion and Tension
A stone of mass 900 g is tied to a string and moved in a vertical circle of radius 1 m making 10 rpm. The tension in the string, when the stone is at the lowest point is (if π² = 9.8 and g = 9.8 m/s²):
  • A. 97 N
  • B. 9.8 N
  • C. 8.82 N
  • D. 17.8 N

Solution

Related Formula

At the lowest point of a vertical circle, the equation of motion for a mass m is:

T - mg = m r ω²

Rearranging to solve for tension T:

T = mg + m r ω²
Core Logic

Given data:

  • Mass, m = 900 g = 0.9 kg
  • Radius, r = 1 m
  • Frequency, N = 10 rpm = (10)/(60) rps = (1)/(6) rps
  • Angular velocity, ω = 2π N = 2π ((1)/(6)) = (π)/(3) rad/s
Step 1: Calculate Force Values

Now we substitute our parameters into the tension equation:

T = (0.9)(9.8) + (0.9)(1)((π)/(3))² T = 8.82 + 0.9 × (π²)/(9)

Since π² = 9.8:

T = 8.82 + 0.1 × 9.8 T = 8.82 + 0.98 = 9.80 N

Free-body diagram of stone at lowest point in vertical circle for Q36
Free-body diagram of stone at lowest point in vertical circle for Q36

Pattern Recognition

Always convert Mass to kg and rotational speed to rad/s first. Using the prompt constraint π² = 9.8 yields a perfect decimal addition match.

Chapter Mix

Class 11 Physics: Laws of Motion

Q59 jee_main_2024_29_january_evening Non-uniform Circular Motion
A particle is moving in a circle of radius 50 cm in such a way that at any instant the normal and tangential components of its acceleration are equal. If its speed at t = 0 is 4 m/s, the time taken to complete the first revolution will be (1)/(α)[ 1 - e-2π ] s, where α = ________.
Numerical Answer. Answer: 8 to 8

Solution

Related Formula

For a particle in circular motion:

  • Normal (centripetal) acceleration: ac = (v²)/(r)
  • Tangential acceleration: aₜ = (dv)/(dt)
Core Logic

Given ac = aₜ:

(v²)/(r) = (dv)/(dt) ∫v₀v (dv)/(v²) = ∫₀t (dt)/(r) [ -(1)/(v) ]v₀v = (t)/(r) -(1)/(v) + (1)/(v₀) = (t)/(r) (1)/(v) = (1)/(v₀) - (t)/(r) v = (v₀)/(1 - (v₀ t)/(r))
Step 1: Relate Velocity to Position and Integrate

Substitute the parameters v₀ = 4 m/s and r = 50 cm = 0.5 m:

v = (4)/(1 - 8t) = (ds)/(dt)

Integrating this to find the position s(t):

∫₀s ds = ∫₀t (4)/(1 - 8t) dt s = 4 [ (ln(1 - 8t))/(-8) ]₀^t = -(1)/(2) ln(1 - 8t)
Step 2: Solve for Time of First Revolution

To complete the first revolution, the distance covered is:

s = 2π r = 2π (0.5) = π m

Equating the distance:

π = -(1)/(2) ln(1 - 8t) -2π = ln(1 - 8t) 1 - 8t = e-2π 8t = 1 - e-2π t = (1)/(8) [ 1 - e-2π ] s

Comparing this to (1)/(α)[ 1 - e-2π ] s, we get:

α = 8

Pattern Recognition

The condition aₜ = ac v (dv)/(ds) = (v²)/(r) (dv)/(v) = (ds)/(r). Integrating directly gives v = v₀ es/r. Substituting this back into v = ds/dt makes the final time integral much more intuitive.

Chapter Mix

Class 11 Physics: Laws of Motion

Q36 jee_main_2024_27_jan_morning Banking of Tracks
A train is moving with a speed of 12 m/s on rails which are 1.5 m apart. To negotiate a curve of radius 400 m, the height by which the outer rail should be raised with respect to the inner rail is (Given, g = 10 m/s²):
  • A. 6.0 cm
  • B. 5.4 cm
  • C. 4.8 cm
  • D. 4.2 cm

Solution

Related Formula
θ = (v²)/(Rg)

For small angles, θ ≈ θ = (h)/(d), where h is the raised height and d is the separation between the tracks.

Core Logic

Equating the two relationships:

(h)/(d) = (v²)/(Rg) (h)/(1.5) = (12 × 12)/(400 × 10)
Step 1: Compute height value
h = 1.5 × (144)/(4000) = 1.5 × 0.036 = 0.054 m

Converting to centimeters:

h = 0.054 × 100 = 5.4 cm
Pattern Recognition

Whenever θ is small, geometry permits approximating θ with hwidth, vastly reducing computational transcendental overhead.

Chapter Mix

Class 11 Physics: Laws of Motion

Q45 jee_main_2024_27_jan_morning Conservation of Linear Momentum
A body of mass 1000 kg is moving horizontally with a velocity 6 m/s. If 200 kg extra mass is added, the final velocity (in m/s) is:
  • A. 6
  • B. 2
  • C. 3
  • D. 5

Solution

Related Formula
m₁ v₁ = m₂ v₂
Core Logic

Since there is no external horizontal force acting on the body, linear momentum along the horizontal axis is conserved.

Initial mass m₁ = 1000 kg, initial velocity v₁ = 6 m/s. Final mass m₂ = 1000 + 200 = 1200 kg.

Step 1: Balance conservation equation
1000 × 6 = 1200 × v₂ 6000 = 1200 v₂ v₂ = (6000)/(1200) = 5 m/s
Pattern Recognition

Inelastic mass addition transitions are classic momentum-balance equations, scaling velocity inversely with total expanded mass profiles.

Chapter Mix

Class 11 Physics: Laws of Motion

More Laws of Motion Questions — jee_main_2026_23_january_evening

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