Does every scientific investigation start with an observation

The isotope 23893Np has a half-life of 2.0 days. If 4.00 grams are produced at noon on Monday, what will be the mass of neptunium remaining at noon on Tuesday of the following week?

A right triangle with base labeled Vector J = 6, the height labeled Vector K = unknown and the hypotenuse labeled Vector L = 10 meters. What is the magnitude of vector K

A pulley stems has an efficiency of 65.1%. If you perform 350 J of work, how much useful work does the pulley perform? A. 350 J B. 301 J C. 228 J D. 122 J

In short-track speed skating, the track has straight sections and semicircles 16 m in diameter. assume that a 64 kg skater goes around the turn at a constant 13 m/s. what is the horizontal force on the skater?

Calculate the force of friction that keeps an 80-kg person sitting on the edge of a horizontal rotating platform when the person sits 2 m from the center of the platform and has a tangential speed of 3 m/s.

You are standing outside during the daytime. How can you see a blade of grass? A. Light is produced by your eyes and travels out to the grass. B. Light is produced by the grass and travels straight to your eyes. C.

Are cosmic rays and gamma rays invisible or do they have color?

What element has the lowest electronegavity?

Identify two different ways you can make a yellow spotlight for a theater stage

Ian walks 2 km to his best friend's house, then walks 0.5 km to the library. He then makes a 2.5 km walk home. The entire walk took him 3 hours. What is his average speed in km/h? SHOW YOUR WORK!