A book is resting on a table. The table is raised on one end to an angle of 15° to the floor. If the book remains at rest, what keeps the book from sliding

Answer

1.2245 s

Explanation

Using the Newton's law of linear motion,

v = u + gt

where v ⇒ Final velocity

            u ⇒ initial velocity,

             t ⇒ time to reach maximum height.

             g ⇒ acceleration due to gravity.

v = u + at

v = 0 m/s

g = -9.8 m/s²  (negative because the velocity is decreasing)

0 = 6 + -9.8t

9.8t = 6

t = 0.612244898 s

This is the time to reach maximum height. It will take the same time to come back to the hand.

so total time = 0.612244898 × 2

                      = 1.2245 s

Answer;

= 4,320,000 joules

Explanation;

Power is the ratio of Work per unit time. When work is done in a given span of time, the ratio of work performed with respect to time is called Power.

Therefore;

Power = Work done/time

Power = 1200 Watts and t = 1 hour or 3600 seconds

Thus;

Work done = Power × time

                   = 1200 ×  3600

                   = 4,320,000 joules or 4320 kJ

Answer:

It can be concluded that groombrige 34 b is more luminous than centauri c since they have the same apparent magnitude.

Explanation:

The apparent magnitude is the brightness that a star appears to have as seen from the earth.

This can variate as a consequence of the distance or radius of the star.

for example, if one of two stars has a bigger radius that a second one, the free mean path of the photons will be higher than in the smaller one, so the bigger one will be more luminous.

In the case of the distance, if for example, two motorbikes with its lights on are approaching an observer, but one of the motorbikes is at a greater distance, it will appear that is light is dimmer compared to the one that is closer. Even if both emit the same amount of light per unit of time.  

Therefore, it can be concluded that groombrige 34 b is more luminous than centauri c since they have the same apparent magnitude.

At certain altitude, the temperature of air decrease, The air becomes saturated and water vapour molecules starts condensing.

As the altitude of air increase, the atmospheric pressure decrease due to which the temperature of the air decrease. The water molecules in the atmosphere start condensing, which saturate the air (that is air can no hold water molecules), due to which the water vapour molecules starts condensing and falls on the earth in the form of rain.