Question

A ball is thrown with a speed of 10 m/s at an angle of 65. which of the following statement describes the motion of the ball at the top of its trajectory

a. the horizontal component of velocity is increasing
b. the horizontal component of velocity is zero
c. the vertical acceleration is zero
d. the vertical acceleration is constant

Answer 1

ans: D
In a projectile motion, horizontal velocity is constant, while the ball is travelling at a constant vertical acceleration due to the gravity (9.81 ms-2 on Earth).

Answer 2

d. the vertical acceleration is constant

Step-by-step explanation:

initial speed of the ball is

`v_i = 10 m/s`

angle of projection

`\theta = 65 degree`

now we will have

`v_x = 10 cos65`

`v_x = 4.23 m/s`

`v_y = 10 sin65`

`v_y = 9.06 m/s`

also we know that there is no external force on the ball in x direction so the speed in x direction will remain same always while in y direction its speed will change due to gravity

So its acceleration in y direction is constant due to gravity