Answer:
A. As the ropes are horizontal the child has travelled 2m of vertical displacement from his lowest position.
Gpe @ A=mgh=40*9.81*2=784.8J
B. At 30degree vertical angle the vertical displacement from lowest position is given by
2-2cos(30)=2-1.73=0.27m
Gpe @B= 40*9.81*0.27=106 J
C: at the bottom of circular arc it's Gpe is zero relative to lowest position as bottom of arc itself is lowest position.
Answer:
0.3659
Explanation:
The power (p) is given as:
P = AeσT⁴
where,
A =Area
e = transmittivity
σ = Stefan-boltzmann constant
T = Temperature
since both the bulbs radiate same power
P₁ = P₂
Where, 1 denotes the bulb 1
2 denotes the bulb 2
thus,
A₁e₁σT₁⁴ = A₂e₂σT₂⁴
Now e₁=e₂
⇒A₁T₁⁴ = A₂T₂⁴
or
![\frac{A_1}{A_2} =\frac{T_{2}^{4}}{T_{1}^{4}}](https://tex.z-dn.net/?f=%5Cfrac%7BA_1%7D%7BA_2%7D%20%3D%5Cfrac%7BT_%7B2%7D%5E%7B4%7D%7D%7BT_%7B1%7D%5E%7B4%7D%7D)
substituting the values in the above question we get
![\frac{A_1}{A_2} =\frac{2100_{2}^{4}}{2700_{1}^{4}}](https://tex.z-dn.net/?f=%5Cfrac%7BA_1%7D%7BA_2%7D%20%3D%5Cfrac%7B2100_%7B2%7D%5E%7B4%7D%7D%7B2700_%7B1%7D%5E%7B4%7D%7D)
or
=0.3659
Explanation:
Trees, because of their height, are natural lightning rods. Electricity seeks the path of least resistance, and the moisture inside a tree is a much better conductor than air. This means a tree provides the preferred path for lightning to reach the ground.
They have the most kinetic energy in the middle of the curve