As a car heads down a highway traveling at a speed v away from a ground observer, which of the following statements are true about the measured speed of the light beam from the car's headlights? (select all that apply.)

a. the ground observer measures the light speed to be c.
b. the driver measures the light speed to be c.
c. the driver measures the light speed to be c − v.
d. the ground observer measures the light speed to be c + v.
e. the ground observer measures the light speed to be c − v.

a and b

Explanation:

According to theory of relativity by great Scientist Albert Eintein the speed of light is independent of frame of reference that the speed of light shall remain constnat whether the frame is inertial or non-inertial.

Therefore, both the ground observer and the driver shall measure same speed of light that is C.

see the picture for the vector

the magnitude of the vector by pythagorean theorem

r = √( (-10)^2 + (3)^2 ) = √109

magnitude = √109 units

the direction angle between vector and x-axis is

tan^(-1)(3/10) = 16.699

so the direction is approximately 16.7 degrees north of west