A ball has been thrown upward. Which of the following is true while the ball is on the way up, after the ball has been released, assuming no air resistance?

a. The acceleration is upward.
b. The acceleration is zero.
c. The ball's speed increases by 9.81 m/s each second.
d. The ball's speed decreases by 9.81 m/s each second.

aaarrrggghhhh !!!!

g is g is g is g = -9.81 m/s^2

so
d

when you throw a ball up, its speed up decreases until it stops !

The acceleration is 9.81 down until it comes back down and hits the ground.

Isn't gravity going upward positive and if it's downward then it would be negative? That's what my teacher told me but I'm pretty sure he said the answer was D too.

our acceleration is 9.81 DOWN, negative

so our UP speed decreases

g = -9.81 m/s^2

gravity does not push UP no matter if you are going up or down

v = Vi + a t

here
v = Vi - 9.81 t

Ok thank you.

To determine the correct answer, let's break down the options and think about the motion of the ball when it is thrown upward without any air resistance:

a. The acceleration is upward.
Acceleration refers to the rate of change of velocity. If the ball is moving upward, then its velocity is also upward. Therefore, the acceleration must be downward to oppose the upward motion and eventually bring the ball to a stop.

b. The acceleration is zero.
If the acceleration were zero, the ball would continue moving at a constant velocity without any change. However, we know that when thrown upward, the ball slows down and eventually changes direction, implying that the acceleration cannot be zero.

c. The ball's speed increases by 9.81 m/s each second.
This statement is not correct. The acceleration due to gravity is always acting downward, regardless of the direction of the ball's motion. Therefore, as the ball moves upward, its speed decreases due to the opposing gravitational force.

d. The ball's speed decreases by 9.81 m/s each second.
This is the correct statement. The acceleration due to gravity is approximately 9.81 m/s², and it acts downward. As the ball moves upward, the force of gravity acts in the opposite direction to its motion, causing its speed to decrease at a constant rate of 9.81 m/s per second.

So, the correct answer is d. The ball's speed decreases by 9.81 m/s each second.