CBSE Class 9 - Science - Work, Energy and Power - Numerical Problems

Work, Energy and Power

Numerical Problems based on Class 9 Physics NCERT Chapter

Q1(CBSE 2012): State the relation between the commercial unit of energy and joules.

Answer: Kilowatt hour (kWh)
        1 kwh - 3.6 x 10⁶ joules


Q2: How much work is done on a body of mass 1kg whirling on a circular path of radius 5m?

Answer: Zero


Q3: A body of mass 15 kg undergoes downward displacement of 40m under the effect of gravitational force. How much work is done? (take g = 10 m/s²)

Answer:
Given
acceleration (a) = g = 10 m/s²
mass (m) = 15 kg
displacement (s) = 40 m

Work W = F × s
  = m × a × s = 15 × 10 × 40 = 6000 J
Since gravitational force and displacement are in the same direction, work is said to be positive and done on the body.



Q4: A body of mass 120 g is taken vertically upwards to reach the height of 5m.  Calculate work done. (Take g = 10 m/s²)

Answer: Given,
      a = g = - 10 m/s²
      m = 120g = 0.120 kg
      s = 5m
      Work W = F × s
 = m × g × s = 0.12 × -10 × 5 = -6 J

       Since Force and displacement act in opposite directions, work is negative. Here work is considered to be done by the body against the applied force.

Q5: A momentum of the body is increased by 20%. What is the percentage increase in its kinetic energy?

CBSE Class 9/10 - Hindi (B) - संधि-विच्छेद

संधि-विच्छेद

दिए गए विकल्पों में से उचित संधि-विच्छेद छांटकर लिखो-

१. प्रत्येक
क. प्रत्य + एक
ख. प्रति + अक
ग. प्रत + एक
घ. प्रति + एक



२. यथेष्ट
क. यथा + इष्ट
ख. यथे + इष्ट
ग. यथे + ष्ट
घ. यथ + इष्ट



३. स्वागत 
क. स्व + आगत
ख. स्वा + गत
ग. सु + आगत
घ. सु + वागत



४. सर्वोत्तम 
क. सर्वो + उत्तम
ख. सर्व + उत्तम
ग. सर्वो + त्तम
घ. सर्वोत्त + म


५. गुरूपदेश 
क. गुरु + उपदेश
ख. गुरू + उपदेश
ग. गुरू + पदेश
घ. गुरूप + देश

CBSE Class 12 - Business Studies - Sample Question Paper (2015)

CBSE Class 12 - Business Studies- Sample Question Paper (2015) 

CBSE Class 6 - Science - CH 8 - Body Movements (Worksheet)

Body Movements

Worksheet based on NCERT Chapter

Types of Joints in Human Skeleton
credits: By OpenStax College
[CC BY 3.0 (http://creativecommons.org/licenses/by/3.0)], via Wikimedia Commons

Fill in the blanks with suitable words.


1. The bony framework which gives shape to the body is called ___________.


2. The skeletal system is comprised of __________, ___________ and _____________.


3. Small bones that make up the back bone are known as _____________.


4. Give an example of pivot joint.

   ____________________________________________________.


5. Movement is brought about by the contraction and relaxation of ____________.

CBSE Class 6 - Social And Political Life- Chapter 4 - Key Elements Of A Democratic Government (Short Q and A)

Key Elements Of A Democratic Government

Short Q & A based on NCERT Chapter

Q.1 What is apartheid?

Answer:  Apartheid means separation or discrimination on the basis of race. South African people were divided into white, black, Indian and coloured races.


Q.2 Which languages were spoken in South Africa?

Answer:  Zulu and Afrikaans were spoken in South Africa.


Q.3 What is the full form of ANC?

Answer: African National Congress. This party led the struggle against Apartheid or racism.


Q.4 Name a famous leader of ANC.

Answer:  Nelson Mandela


Q.5 How often elections are held in India?

Answer:  Elections are held after every five years.

CBSE Class 9 Maths - SA2 - Sample Question Paper (2012)

CBSE Class IX - Maths- SA2- Sample Question Paper (2012) 
The sample paper is based on old pattern, still it is good for practice.

CBSE Class 12 - Business Studies - Marketing vs Selling

Marketing Management

Marketing vs Selling

credits: Wasi at Wikimedia

Q: Distinguish between Marketing and Selling on the basis of

(a) Meaning
(b) Objective
(c) Scope
(d) Importance
(e) Orientation
(f) Point of Start
(g) Approach
(h) Control
(i) Price
(j) Technology Focus

Answer: