What is the frequency of an electromagnetic wave that has a wavelength of 8.5 x 102 m in a vacuum? (The speed of light in a vacuum is 3.00 x 108 m/s.)

A. 1.2 x 10-3 Hz
B. 2.8 x 10-6 Hz
C. 3.5 105 Hz
D. 2.6 x 1011 Hz

➡ ANSWER

☑ C. 3.5 105 Hz

(newtons first law)

conservation of momentum law states :

momentum before collision = momentum after collision

momentum p (kg-m/s)= mass * velocity

say moving car=1 000 kg, velocity = 10 m/s then p = 1 000*10= 10 000 kg-m/s

say still car = 2 000 kg, velocity = 0 m/s then p = 2 000* 0 = 0 kg-m/s

total momentum prior to collision = 10 000 + 0 = 10 000 kg-m/s

momentum after collision = 10 000 kg-m/s

mass now = 1 000 kg+2 000 kg = 3 000 kg

10 000 = 3 000 kg* velocity m/s

10 000/3 000 = velocity

3.33 m/s = velocity after collision

an impulse is a force applied over time , momentum is exclusive of external forces and a perfect collision is implied