 # CBSE Class 11 Physics NCERT Solutions: Chapter 5, Laws of Motion

NCERT questions are a perfect source for extensive practice and getting clear understanding of each topic. So to get the right approach to all NCERT questions read here the NCERT solutions provided for class 11 Physics. Laws of Motion: NCERT Solutions

The questions given in NCERT textbooks at the end of each chapter are not only important for examinations but also to get a clear understanding of the concepts in a better way. That is why students are recommended to read NCERT books thoroughly and practice the exercise questions. Students should try to answer all the NCERT questions to keep a track of their performance.

Consistent practice of solving the NCERT questions helps to break the complex problems in the most efficient way.

Here we are providing NCERT solutions for Class 11 Physics chapter 5, Laws of Motion. All these model solutions have been prepared by the subject experts. So, students who are having trouble finding the right approach to questions given in Class 11 Physics NCERT book, can see the answers given here for reference.

Students may download all the NCERT Solutions for CBSE Class 10 Science chapter – Carbon and its Compounds, in the form of PDF.

Main topics discussed in Class 11 Physics chapter- Laws of Motion are:

• Introduction to basic concepts related to motion of objects
• Aristotle’s fallacy
• The law of inertia
• Newton’s first law of motion
• Newton’s second law of motion
• Newton’s third law of motion
• Conservation of momentum
• Equilibrium of a particle
• Common forces in mechanics
• Circular motion
• Solving problems in mechanics.

CBSE Class 11 Physics Syllabus 2018 - 2019

Some of the questions and their solutions from NCERT Solutions for Class 11: Laws of Motion, are as follows:

Q. A bob of mass 0.1kg hung from the ceiling of a room by a string 2 m long is set into oscillation. The speed of the bob at its mean position is 1 ms-1 what is the trajectory of the bob if the string is cut when the bob is (a) at one of its extreme positions, (b) at its mean position.

Sol.

a) Vertically downward

b) Parabolic path

c) At the extreme position, the velocity of the bob becomes zero. If the string is cut at this moment, then the bob will fall vertically on the ground.

At the mean position, the velocity of the bob is 1m/s. The direction of this velocity is  tangential to the arc formed by the oscillating bob. If the bob is cut at the mean position, then it will trace a projectile path having the horizontal component of velociy only. Hence, it will follow a parabolic path.

Q. Explain why passengers are thrown forward from their seats when a speeding bus stops suddenly.

Sol. When a speeding bus stops suddenly, the lower portion of a passenger’s body, which is in contact with the seat, suddenly comes to rest. However, the upper portion tends to remain in motion (as per the first law of motion). As a result, the pasenger’s upper body is thrown forward in the direction in which the bus was moving.