The equation v=rω says that the tangential speed v is proportional to the distance r from the center of rotation. ... This makes sense because a point farther out from the center has to cover a longer arc length in the same amount of time as a point closer to the center.
Imagine a ball is moving on the following horizontal line.
. . . . . . . . . . . . . . . . . . . O. . . . . . . . . . . . . . . . . .
Take right as positive. O is the starting point of the ball. Denote the ball by o.
. . . . . . . . . . . . . . . . . . . O. . . . . . . ... . . o . . . . . .
Assume the ball is moving to the right. It has positive displacement since it is on the right of O, and positive velocity since its positive displacement is increasing.
.ñ
. . . . . . . . . . . . . . . . . . . O. . . . o . . . . . . . . . . . . .
Now the ball is returning to O. It still has positive displacement since its current position is still on the right of O. However, its velocity is negative since its positive displacement is decreasing and the direction of the velocity vector points left, which is the negative side.
By now you should be able to come up with a scenario where the ball has negative displacement and positive velocity.
You can observe the same phenomenon in daily life. Say, as a stretched spring bounces to its starting position, if we let the returning direction be positive, the string has negative displacement since it is on the negative direction, but has positive velocity. Bungee jump can also used to illustrate the phenomenon.
It’s d because it’s useful output which would be light over total input
7.5/8
Answer:
-36.4 m/s
Explanation:
final velocity= initial velocity + acceleration x time
7 + (-9.8)(3)= -36.4 m/s
Answer:
388.5J
Explanation:
Given parameters:
Weight = 70N
Height = 5.55m
Unknown:
Gravitational potential energy at the top of the ladder = ?
Solution:
The gravitational potential energy is the energy due to the position of the body.
Gravitational potential energy = Weight x height
So;
Gravitational potential energy = 70 x 5.55 = 388.5J
