Abaseball outfielder throws a baseball of mass 0.15 kg at a speed of 40 m/s and initial angle of 30 degrees. what is the kinetic energy of the baseball at the highest point of the trajectory? ignore air friction.
a. zero
b. 30 j
c. 90 j
d. 120

Kinetic energy, E = 90 J

Explanation:

It is given that,

Mass of the baseball, m = 0.15 kg

Speed of projection, v = 40 m/s

Initial angle with horizontal,

At the highest point, the vertical component of velocity is equal to 0. There is only horizontal component of velocity that is given by :

Kinetic energy at the highest point the kinetic energy of the baseball is given by :

E = 89.99 J

or

E = 90 J

So, the kinetic energy of the baseball at the highest point of the trajectory is 90 J. Hence, the correct option is (c).