Physics · Science General

Newtonian Mechanics and Forces

1,559 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 chemistry substances in the surroundings - their states and properties elastic behaviour of solids elastic and plastic substances properties of substances

Fill in the blank.
In a technical sense a substance with a ________ elasticity is one that requires a ______  force to produce a distortion-for example, a steel sphere. 

  1. high, small

  2. high, large

  3. low, large

  4. low , small
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

According to Hooke's law, within elastic limit,

    $E=\dfrac{stress}{strain}$$=\dfrac{deforming\ force}{(area\times strain)}$ 
It means higher the elasticity, larger will be the required deforming force.
Hence, in a technical sense a substance with a high elasticity is one that requires a high force to produce a distortion.

Multiple choice physics properties of material substances elastic behaviour of solids elastic and plastic substances properties of substances

At yield point, Hooke's law doesn't hold good

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The yield point is the point on a stressstrain curve that indicates the limit of elastic behavior and the beginning of plastic behavior. Yielding means the start of breaking of fibers.

Thus, Hooke's law dosent hold good in this region, as stress is not proportional to strain in this region

Multiple choice chemistry substances in the surroundings - their states and properties elastic behaviour of solids elastic and plastic substances properties of substances

An elastic metal rod will change its length when it

  1. falls vertically under its weight

  2. is pulled along its lengthy by a force acting at one end

  3. both

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

An elastic rod changes its length when subjected to a tensile force (being pulled). Falling vertically under its own weight also causes stress and potential elongation, but pulling is the standard demonstration of elastic deformation.

Multiple choice physics rotational motion of a rigid body and moment of inertia constant angular acceleration equation of motion of rotating body dynamics of rotational motion about a fixed axis

A body is given translational velocity and kept on a surface that has sufficient friction. Then:

  1. Body will move forward before pure rolling

  2. Body will move backward before pure rolling

  3. Body will start pure rolling immediately

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

since the body is given initial translational velocity so it will move forward while coming in pure rolling condition.

so the answer is A.

Multiple choice physics turning on a pivot the turning of couple couple turning effect of force the turning effect of a force moment of force or torque

 If principle of moments for any object holds, then object is in state of

  1. inertia

  2. equilibrium

  3. suspension

  4. motion
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

If principle of moments hold good, then the net torque about a given point is zero (usually CM or the pivoted point is zero). Hence the object does not rotate and is said to be in equilibrium

Multiple choice physics dynamics - explaining motion air resistance fluid friction moving through fluids

Fill in the blanks 
Dynamic Fluid friction is _______ the sliding friction of solids.

  1. heigher than

  2. lower than

  3. same as

  4. higher than or equal to
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Friction is the force that opposes motion between any surfaces that are in contact. There are four types of friction: static, sliding, rolling, and fluid friction. Static, sliding, and rolling friction occur between solid surfaces. Fluid friction occurs in liquids and gases.

The maximum limit of static friction is called limiting friction . So,the coefficient of static friction is usually more than that of sliding or kinetic friction. ... Static friction is greater because it works when two surfaces in contact are just to start a relative motion or are in rest.

Multiple choice physics dynamics - explaining motion air resistance fluid friction moving through fluids

The frictional force exerted by fluids is called:

  1. lift

  2. drag

  3. rolling friction

  4. dynamic friction
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Lift is the upward acting force which is against gravity. Drag is the resistance force or friction force in fluid. The rolling friction is a resistive friction when a body rolls on a surface. The dynamic friction is the friction that must be overcome to maintain steady motion of one object relative to another because they remain in contact.

Multiple choice physics dynamics - explaining motion air resistance fluid friction moving through fluids

Fluid friction depends on ______

  1. speed of the object

  2. shape of the object

  3. nature of fluid

  4. all of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The speed of the object moving through a fluid affects the amount of friction acting against the motion of the object. More the speed, more is the friction. If the object is broad, it gives more area for the friction to act on. Thus, a streamlined body structure helps to cut through the fluid and reduce friction. Also, the nature of the fluid affects friction.

Multiple choice physics dynamics - explaining motion air resistance fluid friction moving through fluids

While the arrow moves towards its target, the force acting on it are due to gravity and due to ____ of air.

  1. gravitational force

  2. muscular force

  3. magnetic force

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

When the arrow moves toward target, the force acting on it, is due to gravity and resistive force of air. The resistance force of air is also called as frictional force.