D) blue
(about 400 nanometers)
Answer:
keep adding to on each term its quit simple
Answer : The correct answer is 74.83 m/s .
The kinetic energy is energy possessed by any mass which is moving or have some speed . It is product of mass and velocity . It is expressed as :

Where KE = kinetic energy in J or
m = mass in Kg v = speed in m/s²
Unit of KE is Joules (J) .
Givne : KE = 2100 J mass = 0.75 kg v = ?
Plugging value in KE formula =>


Dividing both side by 0.375 kg =>


