An instrument is thrown upward with a speed of 15 m/s on the surface of planet x where the acceleration due to gravity is 2.5 m/s2 and there is no atmosphere. how long does it take for the instrument to return to where it was thrown?

Explanation:

The situation described here is parabolic movement. However, as we are told the instrument is thrown upward from the surface, we will only use the equations related to the Y axis.

In this sense, the main movement equation in the Y axis is:

   (1)

Where:

 is the instrument's final position  

 is the instrument's initial position

is the instrument's initial velocity

is the time the parabolic movement lasts

 is the acceleration due to gravity at the surface of planet X.

As we know  and when the object hits the ground, equation (1) is rewritten as:

   (2)

Finding :

  (3)

  (4)

  (5)

Finally:

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