I am so sorry, but I do not know what section you are talking about. I hope you find the answer.
Answer:
The angle between the two vectors is 60°
Explanation:
Let A and B represent the two vectors, we have;
Let = a, = b, and = c
We have by cosine rule
c² = a² + b² - 2 × a × b × cos(C)
Where, the angle "C", is the angle between the resultant of the two vectors, a and b and facing the resultant
Given that, a = b = c, we have;
a² = a² + a² - 2 × a × a × cos(C)
a² = 2·a² - 2 × a² × cos(C)
2 × a² × cos(C) = 2·a² - a²
cos(C) = a²/(2·a²) = 1/2
Therefore, angle ∠C = arccosine(1/2) = 60°
The angle between the two vectors = ∠C = 60°.
Answer:
227 m/s
Explanation:
Kinetic energy formula:
- where m = mass of the object (kg)
- and v = speed of the object (m/s)
Let's find the kinetic energy of the 145-g baseball moving at 31.0 m/s.
First convert the mass to kilograms:
Plug known values into the KE formula.
Now we want to find how fast a 2.70-g ping pong ball must move in order to achieve a kinetic energy of 69.6725 J.
First convert the mass to kilograms:
Plug known values into the KE formula.
The ping-pong ball must move at a speed of 227 m/s to achieve the same kinetic energy as the baseball.