The kinetic energy of a man is half that of a boy whose mass is half that of the man. When the man speeds up by 5 m/s, his kinetic energy doubles that of the boy’s kinetic energy. What is the initial velocity of the man?
A. 5 m/s
B. 10 m/s
C. 15 m/s
D. 20 m/s
Answer:A
The kinetic energy of a man is half that of a boy whose mass is half that of the man. When the man speeds up by 5 m/s, his kinetic energy doubles that of the boy’s kinetic energy. What is the initial velocity of the man?
A. 5 m/s B. 10 m/s C. 15 m/s D. 20 m/s