Question

an athlete throws a ball with a velocity of 40 m/s at an angle 20 degree above the horizontal. Which of the following statements is true in this case?A) a vertical component of the velocity remains constant B) the horizontal component of the velocity changes C)the vertical component of the velocity changes sign after the ball attains its maximum height D) the horizontal component of the velocity changes sign after the ball attains its maximum height

Answer 1

The answer is (C) option . As :-

1) There is gravitational force in vertical direction and hence there will be acceleration . So velocity in vertical direction changes and isn’t constant . Hence. (A) is wrong .

2)As there is no force in horizontal direction so velocity in horizontal direction won’t change and so option (B) and (D) are wrong .

3) As there is gravitational force in vertical direction so ball will have positive velocity ( where it overcome gravitational deceleration) and after reaching the highest point the velocity changes the sign as it falls back to ground.