A big lump of meat of mass 5kg is hung from a spring balance in an elevator, find the reading of the balance (I)the elevator is moving with a steady speed.(ii)the elevator is moving upwards with acceleration of 0.2m/s(g=10m/s)

Light from a sodium lamp passes through a diffraction grating that has 1000 slits per millimeter. the interference pattern is viewed on a screen 1.000 m behind the grating. the first (m = 1) two bright yellow fringes that are visible are 0.7288 m and 0.7300 m from the central maximum. what are the wavelengths of these two fringes?

Engineers find a new metal that is stronger than steel but much lighter. this material is also significantly cheaper than what is currently used for most aircraft, available in large quantities, and easy to manufacture. the engineers are excited because this new material will lower the costs of buying and operating airplanes for companies. what is probably the best step for the engineers to make next?

Write down two additional questions about earth's magnetic field that will make your presentation more informative.