Explanation:
Whenever an object is at its highest point, the velocity and acceleration of the object is zero.
Weight equals mass times gravitational acceleration=400N, so mass=400/9.8=41kg approx.
Diffraction patterns are due to interference<span>. Diffraction is a phenomena which occurs when a wave encounters an obstacle. It is the bending of light around the corners if the obstacle.</span>
Acceleration is a derived unit because it is derived from two quantities : Velocity and time.
We know, acceleration = Change in velocity/Time