Question

multiple answer 1 point
a ball is thrown upwards at an angle of 30 degrees from the horizontal. when the ball reaches the top of its path, what must be true? select all statements that are true for the ball at the top of its path.
□ ( v_y ) is equal to 0 m/s
□ ( v_x ) is equal to 0 m/s
□ ( a_y = 0 , \text{m/s}^2 )
□ ( a_y = -9.8 , \text{m/s}^2 )

Explanation:

Step1: Analyze vertical velocity ($v_y$)

At the top of the projectile's path, the vertical motion stops rising, so the vertical velocity component $v_y = 0\ \text{m/s}$.

Step2: Analyze horizontal velocity ($v_x$)

In projectile motion, horizontal velocity ($v_x$) is constant (no air resistance), so $v_x
eq0\ \text{m/s}$.

Step3: Analyze vertical acceleration ($a_y$)

The vertical acceleration is due to gravity, which is $a_y=- 9.8\ \text{m/s}^2$ (downward) throughout the motion, so $a_y
eq0\ \text{m/s}^2$.

Step4: Confirm true statements

From the analysis, $v_y = 0\ \text{m/s}$ and $a_y=-9.8\ \text{m/s}^2$ are true.

Answer:

• $\boldsymbol{v_y}$ is equal to $0\ \text{m/s}$
• $\boldsymbol{a_y}=-9.8\ \text{m/s}^2$