Mechanical Properties of Fluids: Class 11 Physics Q&A
13 free answers on Mechanical Properties of Fluids (Physics) for Class 11 students, across CBSE, ICSE and State boards. Includes questions such as “What is relative density?”, “What is the formula for terminal velocity?”, “How do you convert angular velocity to linear velocity?”
Question & Answer
Questions
- PhysicsClass 11All
What is relative density?
Relative density, also known as specific gravity, is a dimensionless quantity that compares the density of a substance to the density of a reference substance. It is often used in the fields of physics, materials science, and engineering to characterize the density of a material relative to that of another substance, typically water. The relative density (RD) is calculated using the following formula: Relative Density (RD)=Density of the substanceDensi
- PhysicsClass 11All
Why hydrostatic pressure is a scalar quantity even though pressure is force divided by area, and force is a vector?
Since hydrostatic pressure is transmitted equally in all directions therefore we cannot associate direction with pressure. So, hydrostatic pressure is a scalar quantity.
- PhysicsClass 11All
What is the formula for terminal velocity?
Terminal velocity is: v_t = √(2mg/ρAC_d) where m is mass, g is gravity, ρ (rho) is air density, A is cross-sectional area, and C_d is the drag coefficient. Why area matters: Larger area = more air resistance = lower terminal velocity This is why skydivers spread out to slow down and tuck in to speed up Terminal velocity for humans: ~53 m/s (190 km/h) belly-down, ~90 m/s (320 km/h) head-down
- PhysicsClass 11All
How do you convert angular velocity to linear velocity?
Use the formula: v = rω where v is linear velocity, r is the radius from the rotation axis, and ω (omega) is angular velocity in radians per second. Key conversions: If angular velocity is in RPM: ω (rad/s) = RPM × 2π / 60 If angular velocity is in degrees/s: ω (rad/s) = degrees/s × π / 180 Points farther from the axis move fa
- PhysicsClass 11All
What is the formula for finding the velocity of water?
For fluid flow through pipes or channels, use the continuity equation: v = Q/A where Q is volumetric flow rate and A is cross-sectional area. For water exiting from a tank at height h (Torricelli's theorem): v = √(2gh) Example: Water in a tank 5 meters above the outlet exits at v = √(2 × 9.8 × 5) = √98 ≈ 9.9 m/s.
- PhysicsClass 11All
What is linear momentum?
Linear momentum is a fundamental property of a moving object, defined as the product of its mass and velocity. It represents the uantity of motion an object possesses and is a vector uantity, meaning it has both magnitude and direction. The greater an object's mass or velocity, the more momentum it carries. This concept is crucial in understanding collisions, explosions, and the motion of objects in physics.
- PhysicsClass 11All
What is the formula for linear momentum (P)?
The formula for linear momentum is P = mv, where P represents momentum, m is the object's mass (in kilograms), and v is its velocity (in meters per second). For example, a 2 kg ball moving at 5 m/s has a momentum of 10 kg·m/s. This simple yet powerful formula helps predict how objects will behave when forces act upon them.
- PhysicsClass 11All
How do you calculate linear momentum?
To calculate linear momentum, multiply the object's mass by its velocity using the formula P = mv. First, ensure your mass is in kilograms and velocity in meters per second for SI units. Then perform the multiplication. For instance, a 1500 kg car traveling at 20 m/s has momentum of 30,000 kg·m/s. Remember that velocity includes direction, so momentum is also directional.
- PhysicsClass 11All
What is the unit and dimension of linear momentum?
The SI unit of linear momentum is kilogram meter per second (kg·m/s) or euivalently, newton-second (N·s). The dimensional formula is [MLT⁻¹], where M represents mass, L represents length, and T represents time. In the CGS system, the unit is gram centimeter per second (g·cm/s). Understanding these units is essential for solving physics problems correctly.
- PhysicsClass 11All
What is the dimensional formula for linear momentum in Class 11?
The dimensional formula for linear momentum is [M¹L¹T⁻¹] or simply [MLT⁻¹]. This is derived from the formula P = mv, where mass has dimension [M], and velocity has dimension [LT⁻¹]. When multiplied together, they give [MLT⁻¹]. This dimensional analysis helps verify euations and convert between different unit systems in physics problems.
- PhysicsClass 11All
What is the law of linear momentum?
The law of linear momentum, also known as Newton's Second Law, states that the rate of change of momentum of an object euals the net force applied to it. Mathematically: F = ΔP/Δt or F = (mv - mu)/t. Additionally, the Law of Conservation of Linear Momentum states that in a closed system with no external forces, total momentum remains constant before and after any interaction.
- PhysicsClass 11All
What is 70 dyne per cm?
70 dyne/cm is a measurement of surface tension, representing the force per unit length acting along the surface of a liuid. This value is typical for water at room temperature (water's surface tension is approximately 72 dyne/cm). Surface tension measured in dyne/cm indicates how much force is needed to break the surface or how strongly molecules at the surface attract each other.
- PhysicsClass 11All
What is dyne used for?
Dyne is primarily used for measuring small forces in scientific applications, particularly in surface chemistry and biology. It's commonly used to express surface tension (dynes per centimeter), interfacial tension, and other phenomena involving small force measurements. Medical euipment calibration and microfluidics research also freuently employ dynes due to the small forces involved.