﻿ Conceptual Problems on Force| Class 9 physics notes| Class 9 Science notes

# Force Conceptual Problems and Solution

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Question 1
Which is true from Newton's Third law of motion?
a) For every action force there is a 50% reaction force in the opposite direction.
b) For every action force there is an equivalent reaction force in the opposite direction.
c) Both 1 and 2
d): None of the above

Question 2
According to the third law of motion when we push on an object, the object pushes back on us with an equal and opposite force. If the object is a massive truck parked along the roadside, it will probably not move. A student justifies this by answering that the two opposite and equal forces cancel each other. Comment on this logic and explain why the truck does not move?

Question 3
In the equation F = ma, what does m represent?
(a) Mass
(b) Meters
(c) Force
(d) Acceleration

Question 4
Arrange the items in order of increasing inertia?
Bicycle, bus, Train, car, Scooter

Question 5
What is the difference between balanced force and unbalanced force?

Question 6
Newton's First Law of Motion is also called:
a)Law of Friction
b) Law of Reaction
c) Law of Action
d) Law of Inertia

Question 7
State the various effects of force?

Question 8
True and False Statements
A) Momentum is a vector quantity
B) Rate of change of momentum is called Force
C) Inertia is that property of a body due to which it resists a change in its state of rest or of uniform motion
D) when a bullet is fired from the Gun and gun recoil. This is based on law of inertia
E) The unit of momentum is Kg-m
F) Force is a scalar quantity
G) Action –Reaction pair of force act on different body
I) A object can still run with non-zero velocity event the net force acting on the body is zero

Question 9
Give reason for each of these
S.No. Question Reason
1 Why can dust be removed by shaking it, or beating it by a carpet?
2 Why do passengers in the bus tend to fall back when it starts suddenly?
3 Why is it difficult for a fireman to hose, which ejects large amount of water at a high velocity?
4 Why is it advised to tie a rope on the luggage while you travel by the bus?
5 Why do passengers jumping out of a rapidly moving bus fall forward with his face downwards, if he does not run forward?
6 Why the cricket player moves his hand backwards on catching a fast cricket ball
7 What is the use of seat belt in Cars

Question 10
State the Law of Conservation of Momentum. Deduce this from Newton’s second law of motion?