Class 9 NCERT Solutions Work and Energy

Scroll down for PDF

Class 9 NCERT Solutions Work and Energy - NCERT Solutions prepared for CBSE students by the best teachers in Delhi. 

Class IX  Science

Chapter 11 – Work and Energy

Question 1:

A force of 7 N acts on an object. The displacement is, say 8 m, in the direction of the force (Fig. 11.3). Let us take it that the force acts on the object through the displacement. What is the work done in this case?

Answer:

When a force F acts on an object to displace it through a distance S in its direction, then the work done W on the body by the force is given by:

Work done = Force × Displacement

W = F × S

Where,

F = 7 N

S = 8 m

Therefore, work done, W = 7 × 8

= 56 Nm

= 56 J

Question 1:

When do we say that work is done?

Answer:

Work is done whenever the given conditions are satisfied:

(i) A force acts on the body.

(ii) There is a displacement of the body caused by the applied force along the direction of the applied force.

Question 2:

Write an expression for the work done when a force is acting on an object in the direction of its displacement.

Answer:

When a force F displaces a body through a distance S in the direction of the applied force, then the work done W on the body is given by the expression:

Work done = Force × Displacement

W = F × s

Question 3:

Define 1 J of work.

Answer:

1 J is the amount of work done by a force of 1 N on an object that displaces it through a distance of 1 m in the direction of the applied force.

Question 4:

A pair of bullocks exerts a force of 140 N on a plough. The field being ploughed is 15 m long. How much work is done in ploughing the length of the field?

Answer:

Work done by the bullocks is given by the expression:

Work done = Force × Displacement

W = F × d

Where,

Applied force, F = 140 N

Displacement, d = 15 m

 

Students should free download the NCERT solutions and get better marks in exams. Studiestoday.com panel of teachers recommend students to practice questions in NCERT books and download NCERT solutions.

Tags: 


Click on the text For more study material for Science please click here - Science

Latest NCERT & CBSE News

Read the latest news and announcements from NCERT and CBSE below. Important updates relating to your studies which will help you to keep yourself updated with latest happenings in school level education. Keep yourself updated with all latest news and also read articles from teachers which will help you to improve your studies, increase motivation level and promote faster learning

Simple tips to Excel in Examinations

We are entering the last quarter of the Academic Session. With examinations just around the corner, I am sure all of us are carrying a mixed bag of Stress, Excitement, and Anxieties!! So, first and foremost- Let’s be Positive and Futuristic! It’s most important to...

CBSE Counseling for Board exam 2020 starts today

The 23rd psychological Counseling starts 1st February (today) for The Class10 and Class12 CBSE students and their parents, by the Central Board of Secondary Education (CBSE).    This Counseling service is cost-free and this counseling service will be available every...

CBSE Board Exam Date Sheet of class 10th and 12th

The Central Board of Secondary Education (CBSE) released the Date sheet of Class 10 and Class 12th 2020 examination on the official website cbse.nic.in. The board examination of Class 12 will be conducted from 15 February to 30 March 2020, while the board examination...

×
Studies Today