When a body falls freely towards the earth then its total energy

Learning Objectives By the end of this section, you will be able to: • Explain the connection between the constants G G and g g • Determine the mass of an astronomical body from free-fall acceleration at its surface • Describe how the value of g g varies due to location and Earth’s rotation In this section, we observe how Newton’s law of gravitation applies at the surface of a planet and how it connects with what we learned earlier about free fall. We also examine the gravitational effects within spherical bodies. Weight Recall that the acceleration of a free-falling object near Earth’s surface is approximately g = 9.80 m/s 2 g = 9.80 m/s 2. The force causing this acceleration is called the weight of the object, and from Newton’s second law, it has the value mg. This weight is present regardless of whether the object is in free fall. We now know that this force is the gravitational force between the object and Earth. If we substitute mg for the magnitude of F → 12 F → 12 in Newton’s law of universal gravitation, m for m 1 m 1, and M E M E for m 2 m 2, we obtain the scalar equation Masses of Earth and Moon Have you ever wondered how we know the mass of Earth? We certainly can’t place it on a scale. The values of g and the radius of Earth were measured with reasonable accuracy centuries ago. • Use the standard values of g, R E R E, and • Estimate the value of g on the Moon. Use the fact that the Moon has a radius of about 1700 km (a value of this accuracy was determined many...

The correct option is C Remains constant It may be possible that one form of energy will transform into another form of energy viz. Potential energy transforms into the kinetic energy when a body starts to fall from a certain height. But, the total energy (mechanical energy) of the body will always remain constant.

learning objectives • Solve basic problems concerning free fall and distinguish it from other kinds of motion The motion of falling objects is the simplest and most common example of motion with changing velocity. If a coin and a piece of paper are simultaneously dropped side by side, the paper takes much longer to hit the ground. However, if you crumple the paper into a compact ball and drop the items again, it will look like both the coin and the paper hit the floor simultaneously. This is because the amount of force acting on an object is a function of not only its mass, but also area. Free fall is the motion of a body where its weight is the only force acting on an object. Free Fall: This clip shows an object in free fall. Galileo also observed this phenomena and realized that it disagreed with the Aristotle principle that heavier items fall more quickly. Galileo then hypothesized that there is an upward force exerted by air in addition to the downward force of gravity. If air resistance and friction are negligible, then in a given location (because gravity changes with location), all objects fall toward the center of Earth with the same constant acceleration, independent of their mass, that constant acceleration is gravity. Air resistance opposes the motion of an object through the air, while friction opposes motion between objects and the medium through which they are traveling. The acceleration of free-falling objects is referred to as the acceleration due to gravit...

This article needs additional citations for Please help Find sources: · · · · ( October 2017) ( A set of equations describing the g due to Earth’s gravity, F = mg, where F is the force exerted on a mass m by the Earth’s gravitational field of strength g. Assuming constant g is reasonable for objects falling to Earth over the relatively short vertical distances of our everyday experience, but is not valid for greater distances involved in calculating more distant effects, such as spacecraft trajectories. History [ ] The equations ignore air resistance, which has a dramatic effect on objects falling an appreciable distance in air, causing them to quickly approach a The equations also ignore the rotation of the Earth, failing to describe the Overview [ ] Near the surface of the Earth, the g=9.807m/s 2 ( 2 as "feet per second per second") approximately. A coherent set of units for g, d, t and v is essential. Assuming g is measured in meters per second squared, so d must be measured in meters, t in seconds and v in meters per second. In all cases, the body is assumed to start from rest, and air resistance is neglected. Generally, in Earth's atmosphere, all results below will therefore be quite inaccurate after only 5 seconds of fall (at which time an object's velocity will be a little less than the vacuum value of 49m/s(9.8m/s 2×5s) due to air resistance). Air resistance induces a drag force on any body that falls through any atmosphere other than a perfect vacuum, and this dra...

Calculate Potential Energy (PE) for the given mass (m), acceleration of gravity (g) and height (h) through gravitational Question 2. A car is accelerated on a levelled road and attains a velocity 4 times of its initial velocity. In this process the potential energy of the car (a) does not change (b) becomes twice to that of initial (c) becomes 4 times that of initial (d) becomes 16 times that of initial Answer Answer: (a) does not change Question 3. In case of negative work the angle between the force and displacement is (NCERT Exemplar) (a) 0° (b) 45° (c) 90° (d) 180° Answer Answer: (d) 180° Question 4. An iron sphere of mass 10 kg has the same diameter as an aluminium sphere of mass is 3.5 kg. Both spheres are dropped simultaneously from a tower. When they are lo m above the ground, they have the same. (a) acceleration (b) momenta (c) potential energy (d) kinetic energy Answer Answer: (a) acceleration Question 5. A girl is carrying a school bag of 3 kg mass on her back and moves 200 m on a levelled road. The work done against the gravitational force will be (g = 10 ms²) (a) 6 × 10³ J (b) 6 J (c) 0.6 J (d) zero Answer Answer: (d) zero Question 6. Which one of the following is not the unit of energy? (a) joule (b) newton metre (c) kilowatt (d) kilowatt hour Answer Answer: (c) kilowatt Question 7. The work done on an object does not depend upon the (a) displacement (b) force applied (c) angle between force and displacement (d) initial velocity of the object Answer Answer: (...