Due to surface tension, every liquid drop tends to occupy the minimum surface area. For a given volume, the minimum surface area is of sphere. Hence, the liquid drops are spherical in .....

When detergents are mixed with water, the surface tension of the solution decreases. Due to very low surface tension, the detergent mixed water can spread all around and penetrate more between the fibers of material of the clothes, thus increasing .....

We know that Upthrust = Weight of water (Fluid) displaced or, U = Mass of water displaced (m) × g or, U = Volume of water displaced (V) × density of water (ρ) × g      .....

The law of flotation states that "a floating body displaces its weight of fluid." That is, the weight of the body is equal to the weight of the fluid displaced by it. The weight of the fluid displaced is equal to the upthrust (U) exerted .....

If a cork is released from the bottom of a jar filled with water, it comes to the surface of the water at first beacuse the net force acting on it is vertically upwards: it weight acts vertically downwards and upthrust due to water acts vertically .....

Suppose water is filled up mark A in a beaker. When an ice tube is put on the beaker, the cube floats in water raising the level of water in the beaker up to mark B. For the floating ice cube, we have Weight of ice cube = Weight of water .....

A helium-filled balloon rises becasue the weight of air displaced by the balloon is less than its weight that is greater upthrust (U). But, U = Vρg where ρ is the density of the fluid (here it is air) The density of air decreases with .....

The upthrust (U) acting on a body due to a liquid is given U = ρVg, where ρ is the density of the liquid, V is the volume of the liquid displaced and g is the acceleration due to gravity. When the floating body in the liquid .....

In hot air ballooning, a large balloon is filled with air heated by a gas burner at the bottom. Rising the air temperature inside the balloon makes it lighter than the surrounding air. The balloon floats beacuse of the buoyant force exerted on .....

According to Archimede's principle, upthrust ρvg. Since ρ and g are constant for a liquid and at a place, upthrust is directly proportional to the volume of the object inside the liquid. So, larger air bubbles have larger .....

Volume of iceberg = 2060 cm3 Volume of iceberg above sea water = 224 cm3 Density of sea water = 1030 kgm-3 Let ρ be the density of iceberg. The condition of floating is weight of iceberg = weight of water displaced by iceberg or, (2060 .....

Such a type of flow of liquid, in which particles of liquid at the same distance from the axis always have equal velocities directed parallel to the axis, is called laminar flow. For example, a consider a viscous fluid flowing in a pipe of uniform .....

For a smooth-flowing stream of water, the volume of water flowing per second at a point equals to that another point. Hence, from the equation of continuity, we know that the velocity of flow increaes with decreases of cross-section and vice-versa. .....

The antiseptics have low surface tension. Due to the antiseptics spread over the cuts and wounds easily. As a result, the cut or wound is healed .....

Due to the surface tension, every liquid drop occupies the minimum surface area. This is possible only when the liquid drops are spherical in shape. So that the soap bubbles are almost perfect .....

Following are the factors affecting the surface tension of a liquid. a. Contamination: The presence of impurities in a liquid changes its surface tension. b. Temperature: Surface tension of liquid decreases with the rise in temperature. c. .....

We know that the surface tension of a liquid decreases with the increase in temperature. So, the surface tension of hot soup is less than that of the cold one and hence the hot soup spreads over a larger area of the tongue of a person. That makes .....

The shape of a liquid surface in the capillary tube is determined by the relative strengths of cohesive and adhesive force acting on the molecules. If the adhesive force is more than the cohesive, the molecules in the contact with capillary are .....

Mass (m) = 2 kg Extension (x) = 0.1 m Force constant (k) = ? Time period (t) = ? We know, mg = kx \(∴k=\frac{mg}{x}=\frac{2×10}{0.1}=200 N/m\)    ANS \(Again, .....

Here, Mass (m) = 2 kg Force constant (K) = 5.00 N/m Radius (r) = 0.1 m Displacement (x) = 0.08 m We know, \(v=ω\sqrt{r^2-x^2} \) \(or, v = \sqrt{\frac{k}{m}}\sqrt{r^2=x^2} \)     .....

m = 0.1 kg r = 1 m T = 0.2 sec Fmax = ? k = ? \(Since, T=2π\sqrt{\frac{m}{k}} \) \(∴0.2=2π\sqrt{\frac{0.1}{k}} \) \(or, k= .....

Length of a simple pendulum (l) = 4m Amplitude (r) = 0.2m If T is the time period of the simple pendulum, then \(T=2π\sqrt{\frac{l}{g}}=2π\sqrt{\frac{4}{10}}=3.97 seconds \)   (Taking g = 10 .....

Consider a spring PA suspended form fixed point P as shown in the figure. Where a mass m is attached to the free end A of the spring, it stretches to the point O by a length e given by mg = ke ...............(1) where K is the constant of the .....

Characteristics of SHM: i. The displacement of a particle executing SHM at an instant of time represents the distance of the particle from the mean position: y = a sinωt ii. The rate of change of displacement of the particle executing SHM is .....

Let a small body of mass 'm' be suspended by a light helical spring whose one end is fixed to a rigid support as shown in the figure. Now, the mass 'm' is pulled vertically and then released. The mass begins to oscillate about its .....

First part: If a particle moves along a circular path with a constant angular velocity, the projection of the particle describes the circle. This circle is called circle of reference and the particle is called reference particle. When a particle .....

Followings are some drawbacks of a simple pendulum: i. The bob of the simple pendulum can't be a point mass as we assume. ii. The thread is not weightless and inextensible as we assume. iii. The amplitude of vibration of the bob may be .....

Given, y = asin(ωt-ϕ) \(∴v=\frac{dy}{dx}=aωcos(ωt-ϕ) \) acceleration \(a)=\frac{dy}{dx}= -aω^2sin(ωt-ϕ) =-ω^2y .....

The time period for the conical pendulum is \(T=2π\sqrt{\frac{lcosθ}{g}} \) When θ = 0, it gives the time period of a simple pendulum. Hence, in a simple pendulum, there is one less variable than in a .....

The time period of the simple pendulum is given by \(T=2π\sqrt{\frac{l}{g}} \) \(or, \frac{1}{f}=2π\sqrt{\frac{l}{g}} \)    \([∴T=\frac{1}{f}] .....

Here, y = asin(ωt+ϕ) Differentiating twice w.r.t. 't' \(\frac{dy}{dx}=aωcos(ωt+ϕ) \) \(and \frac{d^2y}{dt^2}=-aωsin(ωt+ϕ) \) \(or, a=-ω^2y .....

1st Part: A simple pendulum whose time period is two seconds is called a second's pendulum. From, \(T=2π\sqrt{\frac{l}{g}} \) or, \(2=2π\sqrt{9.8} \)      .....

The time period of the second's pendulum is 2 sec. \(∴2=2π\sqrt{\frac{l}{g}}........(i) \) If T' is the new time period then \(∴T'=2π\sqrt{\frac{l'}{g}} \) .....

We have given, x = 0.05cos(29.t+2.5) Comparing this equation with x= rcos(ωt+ϕ) We get, Amplitude (r) = 0.05 m     Ans ω = 290 or, 2πf = 290 or, \(\frac{2π}{T}=290 \) .....

Time period of a simple pendulum of length l is given by \(T=2π\sqrt{\frac{l}{g}}......(1) \) Let T1 be the time period of the pendulum when its length becomes 4l. .....

The time period of a simple pendulum is given by \(T=2π\sqrt{\frac{l}{g}} \) where l and g are effective lengths of the pendulum and acceleration due to gravity respectively. Thus, the time period (T) depends on the .....

Radius (r) = 1m Mass (m) = 5kg Moment of inertia (I) = 2.5 kgm2 Velocity (v) = 2ms-1 Angular velocity (ω) = ? Total Energy (E) = ? We know, i) v = ωr or, \(ω=\frac{v}{r}=\frac{1}{2}=2rads^{-1} .....

Torque (T) = 500 Nm Moment of inertia (I) = 20 kgm2 Time (t) = 2s We have, τ = Iα or, 500 = 20α or, α = 25 rad s-2 is the angular acceleration. Again, ω = 0 + 25 × 2 ∴ ω = 50 rad s-1 .....

Here, Initial rate of revolution (f1) = 500 rev/min \(=\frac{500}{60}=\frac{25}{3}rev/sec \) Final rate of revolution (f2) = 200 rev/min \(=\frac{200}{60}=\frac{10}{3}rev/sec .....

1st Part Physical meaning of moment of inetria: When a body is in rotational motion, there is a property associated with a body that tends to oppose any change in its state of rest or rotational motion. This property that opposes any change that is .....

First part: Moment of inertia of a rigid body about a particular axis is defined as the sum of the products of the masses of all particles constituting the body and squares of their respective distances from the axis of rotation. .....

We know, torque = force × perpendicular distance form the axis of rotation. A smaller force can produce the same torque if the wrench has a longer arm, we feel easier with a small force. Therefore, we prefer a wrench of a longer arm as .....

Hard (Boiled) egg acts as the rigid while rotating however, the raw egg does not do so beacause of liquid present inside it. As the liquid inside the egg tries to go away from the center which increases the moment of inertia. From the conservation .....

Work done by a force is the product of force and the displacement in the direction of the force applied. i.e. \(W=\overrightarrow{F}. \overrightarrow{r} \) It is scalar quantity. However, the torque is the tunning .....

The earth rotates about an axis passing through its geographic north and south poles with a period of one day. If it is struck by meteroites, then since action and reaction are equal, no external couple acts on the earth and meteorites. Their total .....

Yes. When a force is applied to a body such that the body rolls without slipping on a horizontal plane surface, it rotates about the horizontal axis through the centre of mass and undergoes displacement in the forward direction. In other words, the .....

When a handle or knob is fixed in the end of a door, then the torque produced due to the force about the axis of rotation at the other end becomes quite large as the radius becomes maximum. On the other hand, if the handle is set in other places .....

As the length of the string is increased to revolve a stone in its free end, the distance of the stone from the axis of rotation increases which increases the moment of inertia (I = mr2). As τ = Iα, the large turing force (torque) is .....

When two fingers are used, they exert two forces that are equal in magnitude but opposite in direction and act at different points, that is these two forces form a couple. If a single finger is used, the moment of the force is inadqueate to open the .....

If the ice on the polar caps of the earth melts, the water so formed will spread over the surface and hence the moemnt of inertia of the earth increases about its axis due to a change in the distribution of mass of the particles. According to the .....