Solution1:
0.25 min = 15 secs
a = (v - ) / t
v = 0 (stops to rest), t = 15
⇒ a = -/15
x = t + a
⇒ 10.5 = * 15 + * * 225
10.5 = * 15 -
10.5 = * 7.5
= 1.4 (m/s)
⇒ a = - (m/s^2)
Solution2:
The displacement is a vector that is calculated by subtracting the final and initial positions of an object that has made a movement.
We know that initially the object was at the origin and moved to the -8m position.
Suppose that the movement was made on the x-axis. So:
d = [-8 - (0)]x
d = -8x
Regarding the second question.
When the acceleration is constant then the speed changes at a constant rate. Therefore the graph of velocity vs. time will look like a line with a negative slope (if the acceleration is negative) or a line with a positive slope (if the acceleration is positive)
For example. Suppose that the acceleration of gravity is 10
Now suppose you drop an object from a building.
At the initial moment (second 0) the speed is 0 m/s.
After 1 second the speed of the object will be 10 m/s.
After 2 seconds the speed of the object will be 20 m/s.
After 4 seconds the speed will be 40 m/s.
The graph of this example is shown in the attached figure. Note that it is a straight line.
The second statement is the correct choice. Don't make me type it out.
Mechanical energy is the sum of E potensial and E kinetical
Answer:
(B) Energy cannot be destroyed.
Explanation:
The total amount of energy within a system cannot change. Energy in one form can only be transformed into another form. This implies energy cannot be "destroyed." (neither can it be created from nothing).