At what speed is the momentum of an object five times that found classically?
A)0.894c
B)0.960c
C)0.980c
D)0.800c
E)0.999c

Question

At what speed is the momentum of an object five times that found classically?
A)0.894c
B)0.960c
C)0.980c
D)0.800c
E)​0.999c

Quizplus · Accepted Answer

According to special relativity, momentum is related to the object's velocity by the equation p = mv/(sqrt(1-(v^2/c^2))). If we want the momentum to be five times what it would be classically, we can set p = 5mv and solve for v. This gives v/c = sqrt(1 - 1/25) = sqrt(24/25) = 0.9798, or approximately 0.980c. Choice C is the closest to this value.

At What Speed Is the Momentum of an Object Five