How many neutrons does element X if it's atomic number is 28 and its mass number is 87

Kilogram and second are called fundamental units why

How many of Jupiter's 67 satellites did Galileo discover?

Applying the Law of Conservation of Momentum Train car A is at rest when it is hit by train car B. The two cars, which have the same mass, are stuck together and move off after the collision.

What is meant by the phrase "color by subtraction of light?"

Under the Doppler effect, an observer behind a moving wave source observes A) increased wave frequency B) no wave frequency C) decreased wave frequency D) unchanging wave frequency

Who first described the double-helix structure of DNA?

Suppose you are holding a basketball while standing still on a skateboard you are and the skateboard have a mass of 50 kg you throw the basketball with a force of 10 N what is your acceleration before and after you throw the ball

Which nitrogen base sequence is the partner of C-A-T-C-G-A? O C-A-T-C-G-A O G-T-A-G-C-T OT-G-C-T-A-G O G-C-A-T-G-T TI

What is the kind of energy that comes from movement?

The average kinetic energy of 1 mole of a gas at 273 degrees Celsius is: 6.81 x 103 J 3.40 x 103 J 1.51 x 103 J 6.72 x 101 J