Tag: concept of force and its unit

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

Which is correct for balanced and unbalanced forces?

  1. If set of forces acting on body results in change in state such forces are called unbalanced forces

  2. The vector sum of all forces is zero i.e. $\sum Fx = 0$

  3. The object is in non-equilibrium state and the resultant force is non-zero. i.e. $\sum Fx \neq 0$

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

If a set of forces acting on a body does not change the state of rest or of motion of an object such forces are called balanced forces. In this case object is said to be in equilibrium state. The vector sum of all forces is zero i.e. $\sum Fx = 0$.
Set of forces acting on body results in change in state i.e. either changes the speed or direction, such forces are called unbalanced forces.  In this case the object is in non-equilibrium state and the resultant force is non-zero. i.e. $\sum Fx \neq 0$.

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

The force acting on an object are balanced, then the object:

  1. must be at rest

  2. must be moving

  3. must not be accelerating

  4. must lose energy
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Balanced forces always result in a zero external force acting on an object  i.e  $F _{ext}  =0$

$\therefore$   Acceleration       $a  = \dfrac{F _{ext}}{m}  =  0$
Thus the object must not be accelerating or it must be moving with constant velocity or remain at rest (if it was at rest initially). Hence option C is correct.

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

In tug of war, there are teams A and B. A applies $200 N$ force and B applies $1000 N$ force. Choose the correct statement(s).

  1. The rope will stay at the same place.

  2. The rope will break.

  3. Rope will be drawn towards A.

  4. Rope will be drawn towards B.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Force applied by team A:        $F _A = 200\ N$           (towards A)

Force applied by team B:        $F _B = 1000\ N$         (towards B)

Net force, $F _{net} = F _B-F _A = 1000-200  =800\ N$        (towards B)

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

What kind of force is required to accelerate the motion of an object?

  1. Balanced force

  2. Unbalanced force

  3. Pressurized force

  4. Equal and opposite force
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Unbalanced forces produce a resultant force acting on the object in a particular direction which tends the object to accelerate in that particular direction.

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

On a body, a force of $5N$ is applied towards North and another force of $2N$ is applied towards South. Net force on the body is

  1. $3N$

  2. $7N$

  3. $5N$

  4. $2N$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

When forces are applied inn the opposite directions, the forces get subtracted.
So, net force on the body$=(5-2)N=3N$

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

To move a roller, a force of $300 N$ is required. You alone can produce a force of $30 N$. How many of your friends who are equally strong as you should join you to move the roller?

  1. 9

  2. 10

  3. 5

  4. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Force applied by you $= 30 N =$ force applied by any of your friends.
So, let there be $x$ people in total to push the roller.
When $x$ people, each giving a force of $30N$, give force in same direction, total force = $30xN$
To move the roller, $30x=300$
So, $x=\frac{300}{30}=10$
$\therefore$ number of friends to join you $=(10-1)=9$

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

You are pushing a ball. If your younger sister pushes it from the opposite side with lesser force, the ball will

  1. move slower

  2. move faster

  3. move at same speed

  4. move in another direction
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

When forces are applied from opposite directions, the forces get subtracted. So, the resultant or net force is less than the force which you were applying initially. As a result, the ball will move at a slower speed.