Speed time graph of a ball thrown in the air

Q: What is the acceleration when a ball is thrown in the air?

The cause of the balls acceleration is gravity. The entire time the ball is in the air, its acceleration is 9.8 m/s2 down provided this occurs on the surface of the Earth. Note that the acceleration can be either 9.8 m/s2 or -9.8 m/s2.

1) When a ball is thrown up and it comes downWhen the ball leaves the hand, there is no upward force acting on the ball. The only force acting on the ball is its weight. This net force is opposite to the motion of the ball, hence causing the ball to decelerates. Refer to this post for the explanation (comics)

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There is a new updated post on this concept. Refer to the link below
https://evantoh23.wordpress.com/2020/04/13/displacement-time-and-velocity-time-graph-of-ball-thrown-up-and-comes-down/
What happens to speed when a ball is thrown up?
Which of the following shows speed time graph of a ball thrown upwards?
What is the acceleration when a ball is thrown in the air?

2) When the ball is dropped and it re-bounces back (assume no energy lost)When the ball is released, the only force acting on the ball is its own weight. This net force on the ball is in the direction of the motion, hence causing the ball to accelerate as it falls. Note that the acceleration due to gravity is assumed to be 10 ms-2, where air resistance is negligible.

3) When the ball is dropped and it re-bounces back (in reality with energy lost)

In reality, when the ball hits the ground, there will be some energy converted to heat and sound. So the ball will never return to its original height that it was released. So how will the graphs look like?

There is a new updated post on this concept. Refer to the link below

https://evantoh23.wordpress.com/2020/04/13/displacement-time-and-velocity-time-graph-of-ball-thrown-up-and-comes-down/

A ball is thrown vertically upwards from the hand and lands back onto the hand. It is important to note that once the ball leaves the hand, the resultant force acting on the ball is only its weight! And it is acting downwards throughout the motion.

Click here for a physics comic on this concept
Click here for velocity-time and displacement-time for ball dropping

Velocity-Time Graph

Displacement-Time Graph

Key points to note when sketching the v-t graph:
1) Fixing the direction up to be positive (can be down as positive if you want)
2) At t = 0s, the initial velocity of the ball is maximum.
3) As it goes up vertically, due to the weight acting downwards, the ball decreases in speed (decelerates)
4) At the highest point, the ball is momentarily at rest (v =0m/s)
5) On the way down, due to the weight of the ball acting downward, the ball accelerates downwards.

What happens to speed when a ball is thrown up?

As you throw the ball up into the air, its direction is up, but the speed decreases due to the pull of gravity. The ball slows down, and at the very top of its flight, its velocity at that instant is zero.

Which of the following shows speed time graph of a ball thrown upwards?

In the positive region the velocity decreases linearly (during rise) and in the negative region velocity increases linearly(during fall) and the direction is opposite to each other during rise and fall, hence fall is shown in the negative region. Hence ,the correct option is (D) .

What is the acceleration when a ball is thrown in the air?

The cause of the ball's acceleration is gravity. The entire time the ball is in the air, its acceleration is 9.8 m/s² down provided this occurs on the surface of the Earth. Note that the acceleration can be either 9.8 m/s² or -9.8 m/s².