A 8000 kg engine pulls a train of 5 wagons, each of 2000 kg, along a horizontal track. If the engine exerts a force of 40000 N and the track offers a friction force of 5000 N, then calculate: (a) the net accelerating force and (b) the acceleration of the train.
Solution and Explanation
(a) Net accelerating force = Force exerted by engine–Friction force (Here frictional force is subtracted because it opposes the motion) = 40000 –5000 = 35000 N = 3.5 × 104N
(b) From Newton's second law of motion, Accelerating force = Mass of the train × Acceleration of train a = F ---- m Mass of train = Mass of engine + Mass of all wagons = 8000 + 5 × 2000 = 8000 + 10000 = 18000 kg Acceleration = 35000 = 35 = 1.95ms-2
Top Questions on Inertia and Mass
- What will be the expression for moment of inertia of a rectangular lamina (ABCD having length \(l\) and breadth b) about an axis passing through one of its corners and perpendicular to its plane?
- CUET (PG) - 2023
- Physics
- Inertia and Mass
- Match List I with List II
LIST-I LIST-II A. Green's theorem I. Moment of inertia B. Kepler's laws II. Vectors C. Theorem of parallel and
perpendicular axesIII. Inertia D. Newton's law IV. Motion of planets Choose the correct answer from the options given below:- CUET (PG) - 2023
- Physics
- Inertia and Mass
- Two bodies of different masses are moving with the same kinetic energy. Which one has a greater momentum?
- CUET (PG) - 2023
- Physics
- Inertia and Mass
- An object of mass 1 kg travelling in a straight line with a velocity of 10 m s–1 collides with, and sticks to, a stationary wooden block of mass 5 kg. Then they both move off together in the same straight line. Calculate the total momentum just before the impact and just after the impact. Also, calculate the velocity of the combined object.
- CBSE Class IX
- Science
- Inertia and Mass
- A bullet of mass 10 g traveling horizontally with a velocity of 150 m s–1 strikes a stationary wooden block and comes to rest in 0.03 s. Calculate the distance of penetration of the bullet into the block. Also, calculate the magnitude of the force exerted by the wooden block on the bullet.
- CBSE Class IX
- Science
- Inertia and Mass
Questions Asked in CBSE Class IX exam
Use these adverbs to fill in the blanks in the sentences below.
awfully sorrowfully completely loftily carefully differently quickly nonchalantly(i) The report must be read ________ so that performance can be improved.
(ii) At the interview, Sameer answered our questions _________, shrugging his shoulders.
(iii) We all behave _________ when we are tired or hungry.
(iv) The teacher shook her head ________ when Ravi lied to her.
(v) I ________ forgot about it.
(vi) When I complimented Revathi on her success, she just smiled ________ and turned away.
(vii) The President of the Company is ________ busy and will not be able to meet you.
(viii) I finished my work ________ so that I could go out to play
- CBSE Class IX
- The fun they had
1. ______the firefighters finally put out the fire. (They worked round the clock.)
2. She watched the sunset above the mountain,_____ (She noticed the colours blending softly into one another.)
3. The excited horse pawed the ground rapidly, _____(While it neighed continually.)
4. _____, I found myself in Bangalore, instead of Benaras. (I had taken the wrong train.)
5. _____, I was desperate to get to the bathroom. (I had not bathed for two days)
6. The stone steps,______ needed to be replaced. (They were worn down).
7. The actor received hundreds of letters from his fans, _______(They asked him to send them his photograph.)
- CBSE Class IX
- A truly beautiful mind
- Explain what the reasons for the following are.
(i) Einstein leaving the school in Munich for good.
(ii) Einstein wanting to study in Switzerland rather than in Munich.
(iii) Einstein seeing in Mileva an ally.
(iv) What do these tell you about Einstein?- CBSE Class IX
- A truly beautiful mind
- Were they aware only of their differences or did they also naturally share friendships and experiences? (Think of the bedtime stories in Kalam’s house; of who his friends were; and of what used to take place in the pond near his house.)
- CBSE Class IX
- My childhood
- Why does the world remember Einstein as a “world citizen”?
- CBSE Class IX
- A truly beautiful mind
Concepts Used:
Laws of Motion
The laws of motion, which are the keystone of classical mechanics, are three statements that defined the relationships between the forces acting on a body and its motion. They were first disclosed by English physicist and mathematician Isaac Newton.
Newton’s First Law of Motion
Newton’s 1st law states that a body at rest or uniform motion will continue to be at rest or uniform motion until and unless a net external force acts on it.
Newton’s Second Law of Motion
Newton's 2nd law of motion deals with the relation between force and acceleration. According to the second law of motion, the acceleration of an object as built by a net force is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of the object.
Newton’s Third Law of Motion
Newton's 3rd law of motion states when a body applies a force on another body that there is an equal and opposite reaction for every action.