Newton's Laws of Motion (59 Videos) | Visual Physics

In this video we discuss the difference between the kinematics and kinetics.

First Law - I

In this video we discuss the meaning of force. And understand that the object can not change its state of motion either at rest or motion. And explanation of first law of motion.

First Law - II

In this video we will understand the meaning of net force. And dealing with force in individual direction using vector notation.


A body is acted by three forces as shown. If the body is at rest, find the force F?


If the velocity of an object at given instance is 0, it means that Fnet on that body is zero. (a) True
(b) False


Figure shows the displacement of a particle going along the x axis as a function of time. The force acting on the particle is zero in the region?

Second Law

In this video we understand about the newton second law. And visualizing the relation between the force applied and the acceleration attain by a given mass.


Figure gives four situations in which an object is pulled by several force. In which situations does the objects acceleration a have.
a) an x component and
b) a y component ?
c) In each situation, give the direction of a by naming either a quadrant or a direction along an axis.

Third Law

In this video we understand the meaning of action and reaction. And meaning of free body diagram and the method of drawing free body diagram. Meaning of external and internal forces.


In this video we understand the phenomenon of gravitation. And force of gravity. Meaning of weight of object and mass of object.

Normal Reaction

In this video we deal with the meaning of normal force and contacting force. And different situations for knowing the normal contacting force direction.


In this video we learn what do we mean by tension force. Is there any direction of tension in string? What do we mean by pulling or pushing force. Knowing the variation of tension that can be in string when the string having mass or around a pulley.


Find as many action reaction pairs of forces in this system.


Find normal reaction on the sphere in the following case :


A solid sphere of mass 10 kg is placed over two smooth inclined planes as shown in figure. Normal reaction from the surfaces will be ? (Take g = 10 m/s2)


A sphere of mass m is held between two smooth inclined walls. For sin 370 = 3/5, the normal reaction of the wall (2) is equal to


In figure the value of W is 180 N. Find the tensions in rope A and B.


The weight W1 in Figure is 300 N.
Find T1, T2, T3 and W2.

Spring - I

In this video we will discuss about spring force and its dependency on the change of its length. What is hooks law? Meaning of spring constant. Meaning of ideal spring.

Spring - II

In this video we we will learn how to deal with the cases when the springs are in series, parallel or combination of both. What do we mean by equivalent spring constant?


A mass of 10 kg is suspended from two ideal springs as shown. First spring stretches by 2cms and second by 5cms. Find the spring constant of both the springs.


All surfaces shown in the figure are smooth. System is released with the spring unstretched. In equilibrium, what will be the compression in the spring.


Find the tension in the spring in the given cases. Consider springs, cords and pulleys to be ideal.


Two blocks A and B of masses m and 2m respectively, are held at rest such that the spring is in natural length. Find out the acceleration of both the blocks just after release.

Pseudo Forces 1

In this video we will discuss does Newton?s first law valid in all frames of reference? What are Pseudo Forces?

Pseudo Forces 2

In this video we differentiate the inertial and non inertial frame. and we further discuss about the validation of first and second law in different frame of references.

Pseudo Forces 3

In this video we will learn how to deal with the non inertial frames. And how and in which direction we will apply the pseudo force. And when newtons law can be valid in non inertial frame.


Frame A is accelerating with respect to a point P 1 in the universe Frame B is accelerating with respect to a point P 2 in the universe Frame C is moving with constant velocity with respect to Frame A Frame D is moving with constant velocity with respect to Frame BWe do not know if the reference frame of P 1 or P 2 is inertial or not.
a) Which of the reference frames A, B, C, D are inertial.
b) If Newtons first law is found to be valid in B. Which frames are inertial.
c) If Newtons first law is found to be valid in both Frame A and Frame B what can we say about their relative velocity.


A particle is observed from two frames S 1 and S 2 . The frame S 2 moves with respect to S 1 with an acceleration a. Let F 1 and F 2 be the pseudo forces on the particle when seen from S 1 and S 2 respectively. Which of the following are not possible?
(a) F 1 = 0, F 2 = 0
(b) F 1 = 0, F 2 = 0
(c) F 1 = 0, F 2 = 0
(d) F 1 = 0, F 2 = 0


Statement 1: Newtons first law is merely a special case (a = 0) of the second law.
Statement 2: Newtons first law define the frame from where Newtons second law; F = ma, F representing the net real force acting on a body; is applicable


A particle is found to be at rest when seen from a frame S 1 and moving with a constant velocity when seen from another frame S 2 . Mark out the possible options.
(a) Both the frames are inertial.
(b) Both the frames are noninertial
(c) S 1 is inertial and S 2 is non inertial.
(d) S 1 is non inertial and S 2 is inertial.


Statement 1: A particle is found to be at rest when seen from a frame S 1 and moving with a constant velocity when seen from another frame S 2 . We can say both the frames are inertial.
Statement 2: All frames moving uniformly with respect to an inertial frame are themselves inertial.


A block of mass m is lying on a frictionless surface. It is acted upon by a force F towards right.Find acceleration of the block.


Two blocks connected through a massless in-elastic string are pulled by a force F.
the Tension in the string.


A train of four blocks is being pulled across a frictionless floor by force F. What total mass is accelerated to the right by
a) force F,
b ) cord 3, and
c) cord 1?
d) Rank the blocks according to their acceleration, greatest first.
e) Rank the cords according to their tension, greatest first.


A constant horizontal force F of magnitude 20 N is applied to a block A of mass m 1 = 4.0 kg,which pushes against block B of mass m 2 = 6.0 kg, The blocks slide over a frictionless surface, along an x axis
(a) What is the acceleration of the blocks ?
(b) What is the force exerted by m 1 on m 2 ?


A force F is applied to the system as shown in the figure.Resulting acceleration a of the rope and blocks across the frictionless surface has constant magnitude 2 m/s2. Mass of both the blocks is 5 kgs and mass of the rope is 1 kg. Find


Figure shows a block m 1 lying on a frictionless horizontal surface. The block is connected by a cord that wraps over a frictionless pulley to a second block m 2 . The cord and pulley are massless as compared to the two blocks.
a) Find the acceleration of m 1 and m 2 .
b) Find the tension in the cord.


In Figure three boxes are connected by cords, one of which warps over a pulley having negligible friction on its axle and negligible mass. The three masses are m A = 30.0 kg, m B = 40.0 kg, and m c = 10.0 kg.When the assembly is released from rest, What is the tension in the cord connecting B and C.


A monkey of mass m is climbing on a rope passing over a light frictionless pulley. The opposite end of the rope is tied to a weight of mass M lying on a smooth horizontal plane (see figure). Find the acceleration of both bodies (relative to the plane) and the tension in the rope (neglect mass of pulley and rope), given that the monkey moves upward with an acceleration b relative to the rope.


When two objects are attached by an ideal string passing over an ideal pulley, the arrangement is called an Atwood machine. Determine the magnitude of the acceleration of the blocks and tension in the string.


A 10kg monkey climbs up a massless rope that runs over a frictionless tree limb and back down to a 15kg package on the ground .


Figure shows a man sitting in a chair that dangles from a mass less rope, which runs over a mass less, frictionless pulley and back down to the mans hand. The combined mass of man and chair is M. With what force must the man pull on the rope if he is to rise:
a) with constant velocity and
b) with an upward acceleration of 1.20 m/s2 ?


Figure shows three blocks attached by cords that loop over frictionless pulleys. Block B lies on a frictionless table; the masses are mA = 6.00 kg, mB = 8.00 kg, and mC = 10.0 kg.
When the blocks are released, what is tension in the cord at the right?


In figure a cord pulls on a box up along a frictionless plane inclined at q =300. The box has mass m = 5.00 kg, and the force from the cord has magnitude T = 25.0 N.What is the boxs acceleration component a along the inclined plane?


In Figure a box of mass m = 100kg is pushed at constant speed up a frictionless ramp ( q = 30.0 0 ) by horizontal force F .
What are the magnitudes of
(a) F and
(b) the force on the crate from the ramp?


A sphere of mass m 1 and a block of m 2 are attached by a lightweight cord that passes over a ideal pulley. The block lies on a frictionless incline of angle q as shown in figure.Find the acceleration of the two objects.


In Figure a force F is applied to a mass m2 = 1.0 kg. The force is directed up a plane tilted by q = 37 0 .m2 is connected by a cord to mass m 1 = 3.0 kg on the floor. The floor, plane, and pulley are frictionless, and the masses of the pulley and cord are negligible. What is the tension in the cord? For 1) F = 10 N.2) F = 4 N.


A block A of mass m is tied to a fixed point C on a horizontal table through a string passing round a mass less smooth pulley B. A force F is applied by the experimenter to the pulley. Show that if the pulley is displaced x, the block will be displaced by 2x. Find the acceleration of the block and the pulley.


Consider the situations show in figure. Both the pulleys and the string are light and all the surfaces are frictionless.
a) Find the acceleration of the mass m1 .
b) Find the tension in the string connected to m2 .


There are two objects 1 and 2 placed on smooth horizontal surface. Given that length of the thread is constant. Also that, object 1and 2 move towards right along x- axis. Find out the relation between acceleration of object 1 and 2?


Find the tension in the string ?


Figure shows Atwoods machine, in which two containers are connected by a cord (of negligible mass) passing over a frictionless pulley (also of negligible mass). At time t = 0, container 1 has mass 1.3 kg and container 2 has mass 2.8 kg, but container 1 is losing mass (through a leak) at the constant rate of 0.2 kg/s.
At what rate is the acceleration magnitude of the containers changing at
a) t = 0 and
b) t = 3.00 s?
c) When does the acceleration reach its maximum value?


A ball of mass m is hanging through a string inside a car. The car is moving with an acceleration a towards right.
a) Find the angle q and tension T in the string ?


A bob is hanging over a pulley inside a car through a string. The second end of the string is in the hand of person standing in the car. The car is moving with constant acceleration a directed horizontally. Other end of the string is pulled with constant acceleration a vertically.Find the tension of the string?


Find the mass M of the hanging block in figure, which will prevent the smaller block from slipping over the triangular block? All the surfaces are frictionless and the strings and the pulleys are light.


All the surface shown in Figure are assumed to be frictionless. The block of mass m slides on the prism which in turn slides backward on the horizontal surface. Find the acceleration of the smaller block with respect to the prism.


Three blocks of masses m 1 , m 2 and m 3 are connected as shown in figure. All the surfaces are frictionless and the string and the pulleys are light. Find the acceleration of m 1


What horizontal force must be applied to the cart shown in figure so that the blocks remain stationary relative to the cart? Assume all surfaces and pulleys are frictionless.

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