To find out time, you put distance over speed. So you would have to put 150 over 50. You divide 150 by 50 and you would get 3. So your answer is 3 hours.
To do this we may use things that are good conductors - are painted dull black -
Have a air flow around them Maximised.
explanation
a=average velocity/average time
average velocity=0.0+1.2+2.4+3.6/4
average velocity=7.2/4
average velocity=1.8 m/s
average time=0.0+3.0+6.0+9.0/4
average time=18/4
average time=4.5 s
a= average velocity/average time
a=1.8/4.5
a=0.4 m/s²