NCERT Solutions For Class 11 Physics Chapter 3: Motion in a Straight Line

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NCERT Solutions for Class 11 Physics Chapter 3 Motion in a Straight Line deals with the concepts of Position, path length and displacement, acceleration, kinematic equations, and relative velocity. Motion is the change in the position of an object over a specific period of time with respect to its surroundings. According to Newton’s first law of motion, a body without any net force on it continues to move in a straight line with a permanent velocity until and unless the body is subjected to a net force.

Class 11 Physics Chapter 3 Motion in a Straight Line belongs to Unit 2 Kinematics. Unit 2 along with Unit 1 Physical World and Measurement and Unit 3 Laws of Motion has a weightage of 23 marks. Class 11 Physics Chapter 3 NCERT Solutions covers position-time graphs, calculation of velocity, acceleration, etc.

Download PDF: NCERT Solutions for Class 11 Physics Chapter 3

NCERT Solutions for Class 11 Physics Chapter 3

Read More: Motion in a Straight Line MCQ

Class 11 Physics Chapter 3 – Concepts Covered

An object is in motion if its position changes with time

Based on the position coordinates, motion can be classified as –

(i) One-dimensional motion: A particle in motion along a straight line or a path is said to be in one dimensional motion.
(ii) Two-dimensional motion: A particle in motion in a plane is said to be in two dimensional motion.
(iii) Three-dimensional motion: A particle that is moving in space is said to undergo three dimensional motion.

The total length of the actual path travelled by a particle between its initial and final positions is referred to as the distance travelled by the particle.
Displacement of a particle is the change in the position of a particle in a particular direction during a period of time.

- Displacement has direction while distance does not.

- The magnitude of displacement can be both negative and positive whereas distance is always positive.

Speed is the time rate at which a given object is moving along a path.

An object is said to move with a uniform speed if it covers equal distances in equal intervals of time, howsoever small these intervals may be.

Velocity is the rate and direction of the movement of an object.

An object is said to move with uniform velocity if it covers equal displacements in equal intervals of time, howsoever small these intervals may be.

Class 11 Physics Chapter 3 Related Guides:

Speed and Velocity	Derivation of equation of motion	Frames of Reference
Relative Speed	Uniform Acceleration	Difference between Kinetics and kinematics
Acceleration Time Graph	Path Length	Uniform motion
Average Acceleration Formula	Speed Distance Time Formula	Displacement Formula
Average velocity formula	Average Speed Formula	V-T graphs

Class 11 Physics Study Guides:

NCERT Solutions for Class 11 Physics	Physics Constants	Relation between articles in Physics
Difference between in Physics	Physics Study Notes	SI Units in Physics
Class 11 Physics Notes	Physics Formula	Derivations in Physics

CBSE CLASS XII Related Questions

1.
In a region, the electric potential varies as $V = 10 - 50x$, where $V$ is in volts and $x$ is in meters. The electric field in the region is
- $10\ \text{N/C}$ along $+x$
- $10\ \text{N/C}$ along $-x$
- $50\ \text{N/C}$ along $+x$
- $50\ \text{N/C}$ along $-x$
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2.
A rectangular loop of size 5 cm $\times$ 8 cm is lying in the $x$-$y$ plane in a uniform magnetic field $\vec{B} = (2.0\ \text{T})\hat{k}$. The total magnetic flux linked with the loop is:
- 80 Wb
- 16 Wb
- $8 \times 10^{-2}$ Wb
- $8 \times 10^{-3}$ Wb
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3.
Consider a cylindrical conductor of length $l$ and area of cross-section $A$. Current $I$ is maintained in the conductor and electrons drift with velocity $\vec{v}_d$ ($|\vec{v}_d| = \frac{e|\vec{E}|}{m}\tau$), (where symbols have their usual meanings). Show that the conductivity $\sigma$ of the material of the conductor is given by
$$\sigma = \frac{ne^2}{m}\tau.$$
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4.
A wire of length $L$ is bent round into (i) a square coil having $N$ turns and (ii) a circular coil having $N$ turns. The coil in both cases is free to turn about a vertical axis coinciding with the plane of the coil, in a uniform, horizontal magnetic field and carry the same currents. Find the ratio of the maximum value of the torque acting on the square coil to that on the circular coil.
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5.
(I) The real image of an object placed between $f$ and $2f$ from a convex lens can be seen on a screen placed at the image location. If the screen is removed, is the image still there? Explain.
(II) Plane and convex mirrors produce virtual images of objects. Can they produce real images under some circumstances? Explain.
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6.
Find the ratio $\dfrac{\lambda_\alpha}{\lambda_p}$ of the de Broglie wavelength $\lambda_\alpha$ associated with an alpha particle to the de Broglie wavelength $\lambda_p$ associated with a proton if both are moving with the same velocity.
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