The brightest, hottest, and most massive stars are the brilliant blue stars designated as spectral class O. If a class O star with a mass of 3.38 ´ 1031 kg has a kinetic energy of 1.30 ´ 1042 J, what is its speed?

2.77 * 10^5 m/s

Explanation:

Let us recall that kinetic energy is given by 1/2 mv^2

Where;

m = mass of the body

v = velocity of the body

In this case,

m = 3.38 * 10^31 kg

KE= 1.30 * 10^42 J

KE = 1/2 mv^2

v = √2KE/m

v = √2 * 1.30 * 10^42/3.38 * 10^31

v = √7.69 * 10^10

v = 2.77 * 10^5 m/s

28. evolution

29. environment, survive, offspring  

explanation:

5 w for 1hr = 5x60x60 joules=300x60=3000x6=18,000j as total energy conversion. efficiency of bulb needed for radiant to thermal within 18000