Answer:
T= 4.24sec
Explanation:
We are going to use the formula below to calculate.
Where T is period
L is length of rod
g is acceleration due to gravity = 
From the problem, the rod is pivoted at 1/4L which means that three quarter of the rod was used for the oscillation. lets call this 
= 4.4625m
thus 
T= 4.24sec
The answer is:
V = d/t d = 86 km t = 1.3 hrs
V = 86 km/ 1.3 hrs
V = 66.15 km/ hrs
I hope this helps!!
Although X-rays have many benefits, they can be dangerous to human health because they are short wavelength, high frequency, with photons sufficiently energetic to damage DNA molecules.
Hey again!
Ok..
Now... The melting Point of this solid is 90°C.
Meaning That as soon as it gets to this temp... It STARTS Melting.
So at that temp... It still has some solid parts in it.
You can say its a Solid Liquid Mixture.
Additional Heat being applied at that point is not raising the temperature;rather its used in breaking the bonds in the solid. This is the Fusion stage.
After Fusion...It'd then Be a Pure Liquid with no solids in it.
So
Q'=MC∆0----- This is the heat needed to take the solid's temp from 30°c - 90°c
Q"=ml ----- This is the heat used in breaking the bonds holding the solids in the solid-liquid phase.
So
Q= Q' + Q"
Q= mc∆0 + ml
∆0 = 90°c - 30°c = 60°c
Q= 2.5(390)(60) + (2.5)(4000)
Q=6.9 x 10⁴Joules
