Answer: 
Explanation:
We know that force acting on an object due to Earth's gravity on the surface is given by:
where g is the acceleration due to gravity, r would be radius of Earth, M is the mass of Earth and G is the gravitational constant.
It is given that at pole, g = 9.830 m/s² and r = 6371 km = 6371 × 10³ m
Hence, Earth's mass is 
Answer:
Lubrication is used to reduce friction. It is generally used for moving machine parts. The lubricants are the substances which are used to reduce the friction which acts between two surfaces in contact, between which relative motion can occur.
The thermal energy of an object is the energy contained in the motion and vibration of its molecules. Thermal energy is measured through temperature. The energy contained in the small motions of the object's molecules can be broken up into a combination of microscopic kinetic energy and potential energy.
The thermal energy was produced is 116J
<h3>What is the thermal energy produced?</h3>
Now we know that the frictional force produces the energy that is lost as heat as the body slides down the incline. The magnitude of the frictional force is obtained from;
Ff= μmgcosθ
Ff = 0.65 * 5.0 kg * 9.8 m/s^2 * cos 25
Ff = 29 N
Hence, the thermal energy is;
29 N * 4.0 m = 116J
Learn more about frictional force:brainly.com/question/1714663
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<span>Storm cells in a squall line typically move from the southwest to the northeast, and as the mature cells in the northeast begin to die off, new ones are formed at the opposite end to advance the line. The air in the southwest corner has strong vertical updrafts that allow new cells to grow and develop into thunderstorms.</span>
