an object 5cm in size is placed at 25cm in front of a concave mirror of a focal length 15cm. at what distance from a mirror should a screen be placed inorder to obtain a sharp image?find the nature of size of the image?​

Answer: it will take   4.36 seconds to reach her average velocity 10.69 miles/hour.explanation:   we have equation of motion ,where s is the displacement, a is the acceleration, u is the initial velocity and t is the time taken.average velocity = displacement/ time taken.average velocity = 10.69 miles/hr = 10.69*1.6*1000/(60*60) = 4.75 m/s4.75 = s/ts = 4. 1we also have acceleration = 2.18 m/s², initial velocity = 0 m/sso it will take   4.36 seconds to reach her average velocity 10.69 miles/hour.

Ithink it is a. but i'm not 100 percent sure.

C. it comes from the core of the earth.

Mass and velocity are the 2 factors used to calculate kinetic energy. the equation for kinetic energy is (1/2)mv^2. hope this !