D ....Do you remember your teacher going over different physical and chemical reactions....It is a chemical reaction because it will never go back to the previous state...therefore your correct and it is a chemical reaction.
Answer:
22.26 years
, 15.585 light years , 11.13 light years
Explanation:
a)
= 
= 22.26 years
b)
0.7*c*22.26 years
=15.585 light years
c)
0.7*c*15.9
=11.13 light years
Answer: 2.55meter
Explanation: Using the second equation of motion.
S{hieght} = U*t + {g*t²}/2
Where U is initial velocity =0m/s
g is acceleration due to gravity 10m/s²
t is time 1secs
So we have,
hieght = 0 + {g*t²}/2
hieght = {10*(1)²}/2
Total hieght travelled is 10/2
Which is 5 meter.
But we are asked to find the hieght above the window which as a hieght of 2.45meter.
So,
hieght above window would be
{5 - 2.45}meter
Which is 2.55 meter.
Answer: An object at rest has zero velocity - and (in the absence of an unbalanced force) will remain with a zero velocity. Such an object will not change its state of motion.
Explanation: I hoped that helped!!
To find the ratio of planetary speeds Va/Vb we need the orbital velocity formula:
V=√({G*M}/R), where G is the gravitational constant, M is the mass of the distant star and R is the distance of the planet from the star it is orbiting.
So Va/Vb=[√( {G*M}/Ra) ] / [√( {G*M}/Rb) ], in our case Ra = 7.8*Rb
Va/Vb=[ √( {G*M}/{7.8*Rb} ) ] / [√( {G*M}/Rb )], we put everything under one square root by the rule: (√a) / (√b) = √(a/b)
Va/Vb=√ [ { (G*M)/(7.8*Rb) } / { (G*M)/(Rb) } ], when we cancel out G, M and Rb we get:
Va/Vb=√(1/7.8)/(1/1)=√(1/7.8)=0.358 so the ratio of Va/Vb = 0.358.
