The ans is B) because gravity attracts and doesn't repel
Answer:
66 km
Explanation:
Given that:
The speed of the two trains = 33 km/h
The speed of the bird = 60 km/h
The distance apart between the two trains = 60 km
From the given information, we are being told that the two trains are going at the same speed. Therefore, they will definitely collide at 30 km
We know that:
speed of the train = distance traveled × time
Making the time t the subject of the formula:
time = speed of the train / distance traveled
time = 30 km / 33 km/h
time = 0.909 / hr
Thus, the bird flying at a given speed of 60 km/h in a time of 0.909 / hr will cover a total distance of :
distance (d) = speed of the bird/ time
distance (d) = 
distance (d) = 66 km
Answer:
23 cm
Explanation:
The formula for magnification is;
Magnification = image distance / object distance
use values as;
3.2 = v / 30 where v is image distance
v =30*3.2
v=96 cm
The relationship of the focal length with image distance and object distance is expressed as;

where f is the focal length and u is object distance
use values in the equation as;


f=160/7
f=22.86
f= 23 cm ----------nearest a cm
Answer:
The entropy change of the Universe that occurs is 19.346 J/K
Explanation:
Given;
temperature of the sun,
= 5,300 K
temperature of the Earth,
= 293 K
radiation energy transferred by the sun to the earth, E = 6000 J
The sun loses Q of heat and therefore decreases its entropy by the amount

The earth gains Q of heat and therefore increases its entropy by the amount

The total entropy change is:

Therefore, the entropy change of the Universe that occurs is 19.346 J/K