Please. I need help. I tried solving it but it didn't worked.

We put a force of 50n on an object and the acceleration is 100 m/s². what is the mass of the object?

If a simple machine reduces the strength of a force, what must be increased?

Exercise 2. find the wavelength of a photon emitted when an electron jumps from the n = 3 energy level down to the n = 2 energy level. where is this photon in the electromagnetic spectrum?