Explanation:The side view mirror of a car is a convex lens, so the image distance and focal length are negative. We need to INVESTIGATE the change in distance after one second as seen in the mirror.FORMULA used: In this solution we will be using the following formula; 1f=1v+1u where f is the focal length, v is the image distance in the mirror, u is the object distance. f=R2 where R is the RADIUS of curvature. s=dt where s is the speed of an object, d is the distance covered by the object, and t is the time taken to cover the distance.A man is said to be moving at 5 m/s in real life, we are to calculate his speed as observed in the mirror at a distance of 9m from the mirror.The mirror equation GIVEN by ; 1f=1v+1u where f is the focal length, v is the image distance in the mirror, u is the object distance. First the focal length is f=R2 where R is the radius of curvature. Then, f=22=1mAt the object distance of 9m, the mirror equation can be written as, −11=−1v+19 (because the image distance and focal length can be considered negative for a convex mirror which is the mirror used as side view mirror).Hence, by MAKING 1v subject and calculating, we have 1v=11+19=109Inverting, we have v=910=0.9mNow since speed is given by s=dt where d is the distance covered by the object, and t is the time taken to cover the distance.Hence, after 1 second, the distance covered would be d=5×1=5mThen the new object distance would be u=9−5=4mThen the image distance at this point would be 1v=11+14=54 ⇒v=45=0.8mHence, in the mirror the distance travelled in one second is di=0.9−0.8=0.1m which means speed is 0.1m/s