The speed of sound in hydrogen is about 3.9 times its speed in air. If its speed in hydrogen is almost 1287 m/s, what is its speed in air?

What is the solution of log2  (3x  -  7)  =  3? 4 5

Ascientist wants to use a model to present the results of his detailed scientific investigation. why would a model be useful? a )because the model makes the concepts easier to understand b) because the model is easy to put together and to use c) because the model prevents other scientists from asking questions d) because the model requires the audience to pay full attention to it i don't know what to choose because between a and d a is much more likely than d because it only wants to get the attention of the audience. i'm confuse.

If you could answer these your a life saver