Period = 6 seconds and 
.
<u>Explanation:</u>
We have , the motion of a swing that requires 6 seconds to complete one cycle. Period is the amount of time needed to complete one oscillation . And in question it's given that 6 seconds is needed to complete one cycle. Hence ,Period of the motion of a swing is 6 seconds . Frequency is the number of vibrations produced per second and is calculated with the formula of 
. SI unit of frequency is Hertz or Hz. We know that time period is 6 seconds so frequency =
⇒ 
⇒ 
⇒
Therefore , Period = 6 seconds and .
(a) The velocity of the object on the x-axis is 6 m/s, while on the y-axis is 2 m/s, so the magnitude of its velocity is the resultant of the velocities on the two axes:
And so, the kinetic energy of the object is
(b) The new velocity is 8.00 m/s on the x-axis and 4.00 m/s on the y-axis, so the magnitude of the new velocity is
And so the new kinetic energy is
So, the work done on the object is the variation of kinetic energy of the object:
Explanation:
The triple beam balance is used to measure masses very precisely; the reading error is 0.05g
Use of lubricant
Use of ball bearers
Use of streamlined body
Use of graphite
50km / 2.5 = 20 km per hour
