Answer:
O B. when the angle between the force and displacement is 90°
Explanation:
<h3>work defined as
. </h3><h3>work can only be done if object moves(displacement) in the direction of force. now a quick one. if you since the varrious angles into the cosine, you would see that Cos 90 will give zero which implies that no work is done. Again, angle means it is perpendicular and so it is not in the direction of force.</h3>
Solve for the linear/tangential speed:
<em>a</em> = <em>v</em>²/<em>r</em>
where <em>a</em> = centripetal acceleration, <em>v</em> = speed, and <em>r</em> = radius.
4.7 m/s² = <em>v</em>²/(0.3 m)
<em>v</em>² = (0.3 m) (4.7 m/s²)
<em>v</em> ≈ 3.96 m/s
For every time the record completes one revolution, a fixed point on the edge of the record travels a distance equal to its circumference, which is 2<em>π</em> (0.3 m) ≈ 1.88 m. So if 1 rev ≈ 1.88 m, then the angular speed of the record is
(3.96 m/s) (1/1.88 rev/m) ≈ 7.46 rev/s
Take the reciprocal of this to get the period:
1 / (7.46 rev/s) ≈ 0.134 s/rev
So it takes the record about 0.134 seconds to complete one revolution.
the answer would be the last one because kinetic energy is something in motion.
hope it helps.
Can be numbered in 2 different ways, one box represents one element, and organized by atomic number
