Question

Two particles approach each other with a speed 0.8 c with respect to the laboratory. Their relative speed is ___________

(a) 0.912 c

(b) 0.95 c

(c) 0.975 c

(d) 0.85 c

I got this question by my school principal while I was bunking the class.

Question is taken from Law of Addition of Velocities topic in portion Ultrasonics & Relativity of Engineering Physics I

Answer 1

Correct choice is (c) 0.975 c

The best I can explain: ux = \(\frac{u^{‘}+v}{1+\frac{u^{‘}v}{c^2}}\)

= 0.6c/1.64

= 0.975 c.