Physics · Science General

Newtonian Mechanics and Forces

1,605 Questions

Newtonian mechanics studies the motion of objects and the physical laws governing them. This hub covers friction, gravitational force, inertia, and vector quantities. Mastering these fundamental physics concepts is essential for various government competitive exams.

Laws of motionFriction and inertiaVector and scalar quantitiesGravitational accelerationArchimedes principle

Newtonian Mechanics and Forces Questions

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

A set of unequal and opposite forces is called:

  1. Balanced forces

  2. Unbalanced forces

  3. Equilibrium forces

  4. None
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Unequal and opposite forces do not cancel out each other completely and thus resulting in net force acting in a particular direction. A set of such forces is called a set of unbalanced forces.

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

A number of forces act on a body at the same point and the body does not move. What do you conclude from this?

  1. Body is acted upon by a set of balanced forces.

  2. Body is acted upon by a set of unbalanced forces.

  3. Body is acted upon by a set of unknown forces.

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

Balanced forces cancel out the effect of each other. Thus, no net external force acts on the body and hence a body at rest does not move.

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

If the forces on an object are balanced, then the net force is:

  1. Either positive or negative depending on the strength of forces.

  2. Negative

  3. Positive

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

If the forces on the object are balanced, this means that the individual force cancel out each other resulting in a zero net force acting on the object.

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

Mark the correct statement(s).

  1. When unbalanced forces act on an object at rest, the object will move.

  2. Unbalanced forces are necessary to cause a non-moving object to start moving.

  3. Unbalanced forces produces change in motion (acceleration).

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

Unbalanced forces result in a non-zero net external force acting on a body which produces an acceleration of the body in a particular direction and hence the body at rest starts to move in that direction. Thus unbalanced forces are necessary to cause a non moving object to start moving. Thus option D is correct.

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

You alone can push a roller. But when your friend joins you, the roller moves faster. This is because:

  1. forces in same direction add up.

  2. forces in same direction do not add up.

  3. forces in same direction get subtracted.

  4. forces in same direction remain same.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

When your friend joins you, both of you push the roller in same direction. So, your forces, being applied in same direction, add up to a larger value. Thus the roller moves faster.

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

If force is applied on the body in the direction of motion then

  1. Speed of the body will increase

  2. Speed of the body will decrease

  3. Speed of the body will not change at all

  4. All the options are possible
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

If applied force acts on a body in the direction of motion,the speed of the body will increase.

If the direction of force on the body is opposite to the direction of motion,the speed will decrease.

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

When you and your friend pushed heavy table in the same direction , it becomes easier to move. This is because:

  1. The net force is the sum of forces.

  2. The net force is the difference of force.

  3. The net force is division of forces.

  4. The net force is multiplication of forces.

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

If two forces act on an object in the same direction, the net force is equal to the sum of the two forces. This always results in a stronger force than either of the individual forces alone.

Hence, the net force is the sum of forces

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

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

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.

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

A $5N$ force is applied from one direction on a body and at the same time same force is applied on it from the other side.So,what wil be the result

  1. Body will move towards left

  2. Body will move towards right

  3. Body will not move at all

  4. Body will start rolling at its place
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In general, more than one force may be acting on an object.However,the effect on the object is due to the net force acting on it will be null.

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

If force acts at an angle to the direction of motion,it can

  1. Change the speed of motion

  2. Change the direction of motion

  3. Both

  4. Change the magnitude of the motion

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

If the force acts at an angle to the direction of motion,it can change the speed as well as the direction of motion.