Tag: physics

Quizzes (598) Questions (13441)

Questions Related to physics

Multiple choice physics force and types of force concept of force and its unit force - push or pull forces

Which of the following is/are contact forces

  1. Normal force

  2. Tension force

  3. Friction force

  4. All
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Contact forces are those types of forces which result when the two interacting objects are perceived to be physically contacting each other. Examples of contact forces include frictional forces, tensional forces, normal forces, air resistance forces, and applied forces.

Multiple choice physics forces - vectors and moments concept of force and its unit force - push or pull forces

Which of the following pairs of forces cannot be added to give a resultant force of $4N$?

  1. $2 N$ and $8 N$
  2. $2 N$ and $2 N$
  3. $2 N$ and $6 N$
  4. $2 N$ and $4 N$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Resultant force, 

$F=\sqrt{F _1^2+F _2^2+2F _1F _2cos\theta}$. . . . . . . . .(1)
Lets consider the option A,

$F _1=2N$
$F _2=8N$

For maximum resultant force, $cos\theta=1$
From equation (1),
$F _{max}=\sqrt{F _1^2+F _2^2+2F _1F _2}=\sqrt{(F _1+F _2)^2}$
$F _{max}=F _1+F _2$
$F _{max}=8+2=10N$
For minimum resultant force, $cos\theta=-1$
$F _{min}=\sqrt{F _1^2+F _2^2-2F1F _2}=\sqrt{(F _1-F _2)^2}$
$F _{min}=\sqrt{(2-8)^2}=6N$
So, the $4N$ does not lie within this range. Thus it is not possible to have it as resultant force.
The correct option is A.

Multiple choice physics forces - vectors and moments concept of force and its unit force - push or pull forces

Two forces 12 N and 5 N are acting perpendicular to each other. Then the net force acting is.

  1. 17 N

  2. 18 N

  3. 7 N

  4. zero

  5. 13 N
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

$ \vec F _{net} = \vec F _1 +\vec F _2$

$| \vec F _{net}| = \sqrt{F _1^2 +F _2^2 +2F _1F _2\cos\theta}$
$| \vec F _{net}| = \sqrt{12^2 +5^2 +2\times 12 \times 5\cos 90^0}$
$| \vec F _{net}| = \sqrt{12^2 +5^2 }$
$| \vec F _{net}| = 13N$
Therefore, E is correct option.

Multiple choice physics forces - vectors and moments concept of force and its unit force - push or pull forces

Two forces of $12 \mathrm { N } \text { and } 8 \mathrm { N }$ acts upon a body. The resultant force on the body has maximum value of

  1. $4 \mathrm { N }$
  2. $0 \mathrm { N }$
  3. $20 \mathrm { N }$
  4. $8 \mathrm { N }$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Given,

$|\vec F _1|=12N$
$|\vec F _2|=8N$

The resultant force on the body is 
$|\vec R|=\sqrt{F _1^2+F _2^2+2F _1F _2cos\theta}$

For maximum value, $cos\theta=1$
$|\vec R|=\sqrt{(12)^2+(8)^2+2\times 12\times 8\times 1}$

$|\vec R _{max}|=\sqrt{144+64+24\times 8}$

$|\vec R _{max}|=\sqrt{400}=20N$
The correct option is C.

Multiple choice physics force concept of force and its unit force - push or pull forces

Fill in the blanks:
The net force is ______ than the individual applied forces.

  1. either larger or smaller

  2. always smaller

  3. always greater

  4. always equal
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The net force is either sum or difference of individual applied forces. So, the force is either larger or smaller than individual forces.

Multiple choice physics force concept of force and its unit force - push or pull forces

In tug of war, if the two teams have equal strength then:

  1. the rope will break.

  2. the rope will stay at the same place.

  3. the rope will move towards one of the sides.

  4. the rope will move towards each end alternatively.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The rope breaks only if the force applied by both the teams is very large. It has nothing to do with the equality of the strength in the teams on the two sides of the rope.
In a tug of war, if the two teams are applying equal force on the rope then the net force acting on the rope is zero and hence the rope stays at the same place.