Answer:
It would eventually crash into the Sun
Explanation:
If the mars is orbiting around the sun, the gravitational force of attraction is between the sun and mars supply the necessary force required for the centripetal motion.
If a planet is in centripetal motion, it is constantly falling towards the sun with the acceleration equal to the gravitational strength at that point.
If the centripetal acceleration of the planet is removed, still the planet would accelerate linearly falling towards the sun.
Hence, if the planets tangential velocity was reduced to zero, It would eventually crash into the Sun