General Q&A for Class 12 · Page 199
5,215 free answers in General for Class 12 students, across CBSE, ICSE and State boards.
Question & Answer
Questions
- GeneralClass 12All
What is the euation for linear momentum and impulse?
The impulse-momentum euation is Impulse = ΔP or F·Δt = mv - mu. Impulse is the change in momentum caused by a force acting over a time interval. This euation shows that applying a force F for time Δt changes an object's momentum from its initial value (mu) to its final value (mv). This principle explains why airbags and crumple zones in cars reduce injury during collisions.
- GeneralClass 12All
How do you derive linear momentum?
Linear momentum is derived from Newton's Second Law. Starting with F = ma (force euals mass times acceleration), and knowing that acceleration a = (v - u)/t (change in velocity over time), we can write F = m(v - u)/t. Rearranging gives Ft = mv - mu, where mv and mu represent final and initial momentum respectively. This derivation shows that force applied over time changes an object's momentum.
- GeneralClass 12All
How is gravity 9.8 calculated?
The value 9.8 m/s² is calculated using Newton's law of universal gravitation. When you apply the formula F = G(m₁m₂)/r² to Earth's mass (5.972 × 10²⁴ kg) and radius (approximately 6.371 × 10⁶ meters), then divide by the mass of the object (since F = mg), you get g = GM/r². Plugging in Earth's mass and radius gives approximately 9.8 m/s². This value represents how uickly objects accelerate toward Earth when falling freely, increasing their velocity by 9.8 m
- GeneralClass 12All
What is Newton's 3rd law of gravity?
Newton's third law (often called the law of action and reaction) states: For every action, there is an eual and opposite reaction. Applied to gravity, this means that if Earth pulls on you with a certain force, you pull on Earth with exactly the same force in the opposite direction. When you stand on the ground, Earth's gravity pulls you downward with your weight, and simultaneously, you pull Earth upward with an eual force. We don't notice Earth moving because its enormous mass makes the acc
- GeneralClass 12All
What are Newton's 1st, 2nd, and 3rd laws?
Newton's First Law (Law of Inertia): An object at rest stays at rest, and an object in motion stays in motion at constant velocity, unless acted upon by an external force. Newton's Second Law (F = ma): The force acting on an object euals its mass multiplied by its acceleration. This law explains how the velocity of an object changes when it's subjected to an external force. Newton's Third Law (Action-Reaction): For every actio
- GeneralClass 12All
What is the basic law of gravity?
The basic law of gravity, formulated by Isaac Newton, states that every particle of matter in the universe attracts every other particle with a force that is directly proportional to the product of their masses and inversely proportional to the suare of the distance between them. In simpler terms: the more massive objects are, the stronger their gravitational attraction, and the farther apart they are, the weaker the attraction becomes (following an inverse-suare relationship). This law expla
- GeneralClass 12All
How to calculate mass using gravity?
To calculate mass using gravity, rearrange the weight formula F = mg to get: m = F/g or m = W/g Where: m = mass (in kilograms) F or W = weight/force (in Newtons) g = acceleration due to gravity (9.8 m/s² on Earth) For example, if an object weighs 98 Newtons on Earth, its mass would be 98 ÷ 9.8 = 10 kg. Remember that mass is constant regardless of location, while weight changes depending on the gravitational field strength.
- GeneralClass 12All
Is gravity 9.8 or 32?
Both values are correct they just use different unit systems. Gravity is 9.8 m/s² in the metric system (meters per second suared) and 32 ft/s² (more precisely 32.2 ft/s²) in the imperial system (feet per second suared). Scientists and most countries use the metric value of 9.8 m/s², while the imperial measurement is sometimes used in the United States. Both describe the same physical phenomenon: how uickly objects accelerate when falling toward Earth.
- GeneralClass 12All
How much Newton is gravity?
Gravity itself isn't measured in Newtons Newtons measure force. The force of gravity (weight) depends on mass. Using the formula F = mg, a 1 kg mass experiences 9.8 Newtons of gravitational force on Earth's surface. A 10 kg object experiences 98 N, a 70 kg person experiences about 686 N, and so on. The acceleration due to gravity (g) is 9.8 m/s², which can also be expressed as 9.8 N/kg, meaning each kilogram of mass experiences 9.8 Newtons of gravitational force.
- GeneralClass 12All
What is the normal gravity number?
The normal or standard gravity value is 9.80665 m/s² (often rounded to 9.8 m/s²), also denoted as 1 g. This represents Earth's average gravitational acceleration at sea level. It serves as the reference point for measuring other gravitational environments. For example, the Moon's surface gravity is about 0.16 g (1/6th of Earth's), Mars has about 0.38 g, and Jupiter's surface gravity is approximately 2.5 g. This standard value is used worldwide in physics calculations and engineering
- GeneralClass 12All
What is 1 gravity?
"1 gravity" (written as 1 g) refers to Earth's standard gravitational acceleration of 9.8 m/s². It's used as a reference unit to describe gravitational or acceleration forces relative to what we experience on Earth's surface. When astronauts experience "0 g" in orbit, they're in freefall. Fighter pilots might experience "5 g" during sharp maneuvers, meaning they feel five times their normal weight. "1 g" is also used to describe the comfort level for humans our bodies ev
- GeneralClass 12All
What does 9.8 mean in gravity?
The number 9.8 represents the rate of acceleration (in meters per second suared) that gravity causes on objects near Earth's surface. It means that for every second an object falls (ignoring air resistance), its velocity increases by 9.8 meters per second. After 1 second of falling, an object reaches 9.8 m/s; after 2 seconds, it's moving at 19.6 m/s; after 3 seconds, 29.4 m/s, and so on. This constant acceleration is why falling objects speed up continuously rather than falling at a steady sp
- GeneralClass 12All
What is the gravity of 9.8 kg?
This uestion contains a common misconception. "9.8 kg" doesn't describe gravity—it mixes units incorrectly. Gravity's acceleration is 9.8 m/s² (not kg). If you have a 9.8 kg mass, its weight (gravitational force) on Earth would be: F = mg = 9.8 kg × 9.8 m/s² = 96.04 Newtons. Kilograms measure mass (the amount of matter), while gravity is measured as acceleration (m/s²) or force (Newtons).
- GeneralClass 12All
Could a human survive 2x gravity?
Humans could survive 2 g (double Earth's gravity) for extended periods, but it would be extremely challenging and potentially harmful long-term. At 2 g, everything would weigh twice as much, including your body. Standing and walking would reuire enormous effort, your cardiovascular system would strain to pump blood against increased weight, and prolonged exposure could lead to bone stress, joint problems, and organ compression. Fighter pilots and astronauts sometimes experience 2-3 g during t
- GeneralClass 12All
What is uantum gravity?
uantum gravity is a theoretical framework that attempts to describe gravity according to the principles of uantum mechanics. Currently, gravity is explained by Einstein's general relativity (which works beautifully at large scales), while uantum mechanics governs the atomic and subatomic world. However, these two theories are fundamentally incompatible. uantum gravity seeks to unify them into a single consistent theory that works at all scales, especially at the extremely sma
- GeneralClass 12All
Is gravity a force?
This uestion has two answers depending on your physics framework. In Newtonian physics, yes gravity is absolutely a force that attracts objects with mass. In Einstein's general relativity, no gravity isn't a force but rather the curvature of spacetime caused by mass and energy. Objects follow the straightest possible paths through this curved spacetime, creating what we perceive as gravitational attraction. For everyday applications and most calculations, treating gravity as a force (F = mg)
- GeneralClass 12All
What if gravity is zero?
If gravity suddenly became zero, the conseuences would be catastrophic. Earth's atmosphere would immediately disperse into space since nothing would hold it down. Oceans, lakes, and all water would float away. People, animals, buildings, and objects not anchored down would drift into space. Earth itself would disintegrate since gravity holds the planet together. The Moon would fly off on a tangent rather than orbiting. The Sun would explode without gravity compressing its core to sustain nucl
- GeneralClass 12All
What is gravity force?
Gravity force (also called weight) is the attractive force that gravity exerts on an object with mass. It's calculated using F = mg, where m is the object's mass and g is gravitational acceleration. On Earth's surface, gravity force euals an object's weight in Newtons. For example, a 10 kg bowling ball experiences a gravity force of 98 N downward. This force is what you feel when you hold something you're resisting its weight. Gravity force varies depending on location: the same object weighs
- GeneralClass 12All
How much is gravity?
Earth's gravity is 9.8 m/s² or 9.8 N/kg at sea level. This means each kilogram of mass experiences 9.8 Newtons of gravitational force. The strength varies slightly by location—it's about 0.5% stronger at the poles than the euator, and decreases with altitude (about 0.03% less per kilometer above sea level). Other celestial bodies have different gravitational strengths: the Moon has 1.63 m/s², Mars has 3.71 m/s², and Jupiter has 24.79 m/s². In terms of gravitational c
- GeneralClass 12All
What is electric current?
Electric current is the flow of electric charge through a conductor, such as a wire. It occurs when electrons move from one point to another, creating a continuous stream of electrical energy. Current flows from a region of higher potential (positive terminal) to lower potential (negative terminal) in a circuit. The movement of these charged particles is what powers electrical devices, from light bulbs to smartphones. Current can only flow in a complete circuit, which is why switches work by