In the 18th Century some scientists thought that the energy produced by the Sun was the result of chemical reactions. Which discovery would make this hypothesis doubtful? A) The Sun is made of gas

B) Heat is absorbed or released in chemical reactions.

C) Chemical reactions can take place at very high temperatures.

D) Energy is released when hydrogen nuclei fuse into helium nuctel.

the minimum constant speed at which she can catch the train is 2.7 m/s

given:

acceleration = 0.6

time = 4.5 s

to find:

velocity = ?

formula used:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

solution:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

v = 0 + (0.6 × 4.5)

v = 2.7 m/s

the minimum constant speed at which she can catch the train is 2.7 m/s

i think it would be 5

a. vertically

explanation:

i tried it and took the test

if im wrong then we have different tests