Knee sprains can be classified into three grades, depending on the amount of damage: Grade 1: a few fibres (less than 10%) are damaged/torn. Usually heals naturally. Grade 2: more fibres are torn but the ligament is still intact. Grade 3: the ligament is ruptured ie completely torn.
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Answer:
Answer in Explanation
Explanation:
Whenever we talk about the gravitational potential energy, it means the energy stored in a body due to its position in the gravitational field. Now, we know that in the gravitational field the work is only done when the body moves vertically. If the body moves horizontally on the same surface in the Earth's Gravitational Field, then the work done on the body is considered to be zero. Hence, the work done or the energy stored in the object while in the gravitational field is only possible if it moves vertically. This vertical distance is referred to as height. <u>This is the main reason why we require height in the P.E formula and calculations.</u>
The derivation of this formula is as follows:
Work = Force * Displacement
For gravitational potential energy:
Work = P.E
Force = Weight = mg
Displacement = Vertical Displacement = Height = h
Therefore,
P.E = mgh
Answer:
The height (in m) above the floor of the top and bottom of the smallest mirror in which he can see both the top of his head and his feet is;
1.835 m and 0.88 m.
Explanation:
Here we have the total height of the man as
1.76 + 0.15 = 1.91 m
The mirror is positioned such that the person can see both the top of his head and his feet
We have the eyes are 0.15 m below the top of the head, therefore by the law of reflection, the incident and reflected angle must be equal.
Hence, the light from the top of his head and then reflected to his eyes forms a isosceles triangle, with the base being the distance of the eye to the top of his head and the top of the triangle is on the mirror.
The height of the mirror is then
1.91 - 0.15/2 = 1.835 m
Similarly, the distance from the eye to the feet is 1.76, therefore, the base of the mirror is positioned at 1.76/2 or 0.88 m above the ground.
Answer:
a) 
, b) 
Explanation:
a) The final velocity of the 13.5 g coin is found by the Principle of Momentum Conservation:
The final velocity is:
b) The change in the kinetic energy of the 13.5 g coin is:
![\Delta K = \frac{1}{2}\cdot (13.5\times 10^{-3}\,kg)\cdot \left[(11.9\times 10^{-2}\,\frac{m}{s} )^{2}-(0\,\frac{m}{s} )^{2}\right]](https://tex.z-dn.net/?f=%5CDelta%20K%20%3D%20%5Cfrac%7B1%7D%7B2%7D%5Ccdot%20%2813.5%5Ctimes%2010%5E%7B-3%7D%5C%2Ckg%29%5Ccdot%20%5Cleft%5B%2811.9%5Ctimes%2010%5E%7B-2%7D%5C%2C%5Cfrac%7Bm%7D%7Bs%7D%20%29%5E%7B2%7D-%280%5C%2C%5Cfrac%7Bm%7D%7Bs%7D%20%29%5E%7B2%7D%5Cright%5D)
