Answer:

Explanation:
Diffraction is observed when a wave is distorted by an obstacle whose dimensions are comparable to the wavelength. The simplest case corresponds to the Fraunhofer diffraction, in which the obstacle is a long, narrow slit, so we can ignore the effects of extremes.
This is a simple case, in which we can use the Fraunhofer single slit diffraction equation:

Where:

Solving for λ:

Replacing the data provided by the problem:

Answer:
120 N
Explanation:
F=ma therefore 60kg times 2m/s^2 is 120 N
The mass of an object always stays the same since it is really just the amount of matter in an object so no matter the force applied, as long as the object does not lose or gain matter, the object stays the same