Question

1 multiple choice 1 point what is the acceleration due to gravity? select the answer with the correct numerical value with the correct units. -4.9 m/s -4.9 m/s² -9.8 m/s -9.8 m/s² 2 multiple choice 1 point a student throws a ball straight up. as the ball travels upwards what happens to the balls speed? the speed increases by 4.9 m/s each second as the ball rises the speed decreases by 4.9 m/s each second as the ball rises the speed increases by 9.8 m/s each second as the ball rises the speed decreases by 9.8 m/s each second as the ball rises

Explanation:

Step1: Recall gravity - acceleration value

On Earth, the acceleration due to gravity near the surface is approximately $9.8\ m/s^{2}$. The negative sign is used when the upward - direction is considered positive (as gravity acts downwards). The unit of acceleration is $m/s^{2}$.

Step2: Analyze ball's upward motion

When a ball is thrown upwards, the acceleration due to gravity acts in the opposite direction of its motion. The acceleration due to gravity is $a=- 9.8\ m/s^{2}$. Using the kinematic equation $v = v_0+at$, where $a=-9.8\ m/s^{2}$, each second the velocity (speed in the non - vector sense here as we are just talking about magnitude change) decreases by $9.8\ m/s$.

Answer:

1. D. $-9.8\ m/s^{2}$
2. D. The speed decreases by 9.8 m/s each second as the ball rises