Question

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Answer 1

15. Stored energy or energy due to position is known as  gravitational potential energy . Gravitational potential energy is the energy due to the position of an object in a gravitational field.

16. The formula for calculating potential energy is

$U=mgh$

where m is the mass of the object, g is the gravitational acceleration and h the heigth of the object above the ground.

17. The three factors that determine the amount of potential energy in an object are :

- the mass

- the acceleration of gravity, g

- the height of the object relative to the ground

18. Potential energy is measured in units of  Joules. Potential energy is a form of energy, so it is measured in Joules (J), which is the SI unit of the energy.

19 Mass must be measured in units of  kilograms (kg). Mass is a scalar quantiy expressing the amount of matter in an object; the SI unit of the mass is the kilogram, kg.

20. Gravitational pull must be measured in units of  Newton (N). Gravitational pull is a force, therefore it is measured in Newtons.

21. The value of the g constant (the acceleration of all objects due to gravity) on earth is $9.8 m/s^2$. The acceleration of gravity is the acceleration due to the force of gravity, pulling all objects towards the Earth's centre. Its value is slightly different at different locations on Earth.

22. Height must be measured in units of  metres (m). Height is a length, and the SI unit of the length is the metre.

23. Kinetic energy is the energy matter has as a result of its mass

and  speed. In fact, the kinetic energy of an object is given by

$K=\frac{1}{2}mv^2$

where m is the mass of the object and v its speed.

24. The more mass an object has the more Kinetic energy it has. As we can see from the previous formula, kinetic energy is proportional to the mass, so the more mass an object has, the more kinetic energy it has.

25. The more speed an object has the more Kinetic energy it has.  As we can see from the previous formula, kinetic energy is proportional to the square of the speed, so the more speed an object has, the more kinetic energy it has.

26. The SI (metric) unit for energy is  Joule and the symbol is J.