D = distance between th two trains at the start of the motion = 100 miles
V = speed of the faster train towards slower train = 60 mph
v = speed of the slower train towards faster train = 40 mph
t = time taken by the two trains to collide = ?
time taken by the two trains to collide is given as
t = D/(V + v)
t = 100/(60 + 40) = 1 h
v' = speed of the bird = 90 mph
d = distance traveled by the bird
distance traveled by the bird is given as
d = v' t
d = 90 x 1
d = 90 miles
It depends on how many hours!
1 hour = 40km
2 hours = 80km
Models help us to understand systems and their properties
Explanation:
SUPONIENDO QUE LA ACELERACIÓN DE LA GRAVEDAD ES 
USANDO LA SEGUNDA LEY DE NEWTON:
<em>m</em> = 80.0 N/ = 8.16 kg
<h3><u>Effects of the earths orbit around the sun:</u></h3>
The earth moves around the sun in an elliptical orbit, Johannes Kepler, a "German mathematician, and astronomer" described this elliptical orbit first. The orbit is close to being a circle but not a circle. Earth orbiting the sun mainly effects on seasons on earth.
Earth's four seasons are determined when Earth is tilted 23.4 degrees on the vertical axis, which is called as “axial tilt”. When a "southern hemisphere is tilted towards the sun", it experiences summer and northern hemisphere experiences winter, exactly opposite happens when northern hemisphere tilts towards Sun and this climate change goes on in all countries.
