Forces MCQ - Practice Questions & Answers

Solve by difficulty

There are two forces; their magnitude’s summation is 40 N and the resultant of them is 20N; The resultant force is perpendicular to the smaller force; The magnitudes of their forces are :

30 and 10

28 and 12

25 and 15

21 and 19

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Assertion: When two perpendicular forces are there and the sum of their magnitude is 20N; Then the resultant of these forces is 14.42 N

Reason: Value of two forces 12 and 8

The assertion is true; the Reason is False

The reason is true; the Assertion is False

Reason and Assertion both are true; Reason is the correct explanation for assertion

Reason and Assertion both are false

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Concepts Covered - 1

Forces

Definition- Force is defined as an effect which causes a body to change its state.

Force on 1 kg mass in the presence of gravity ( $g=9.8 m/s^2$ ) is 1 kg-f=9.8 N
Unit of force-

In SI unit- Newton(N)
In CGS- 1 dyne (1 newton = 100000 dyne)

1 Newton(N) is the force needed to accelerate an object with a mass of 1 kg at a rate of 1 m/s² (1 N = 1 kg · m/s²)

2. Types of forces-

a) Contact forces-

Contact forces are due to direct physical contact between objects.

Types of contact forces-

Tension
Normal reaction
Spring force
Friction

b) Non-contact forces-

These forces act without the necessity of physical contact between objects.
They depend on the presence of a “field” in the region of space surrounding the body under consideration.

Types of non-contact forces-