# What happens when a ball is thrown vertically in the air?

• stephi
In summary, the conversation discusses the question of which quantities are zero when a ball reaches maximum height after being thrown vertically in the air. The answer is that both speed and velocity are zero at the top, as velocity is the vector quantity and speed is its magnitude. The conversation also mentions the possibility of asking for help with a difficult math problem.

## Homework Statement

A ball is thrown vertically in the air, upward from the surface of the Earth. Which of the following quantities are zero when the ball reaches maximum height?
a)speed b)velocity c)acceleration

## The Attempt at a Solution

i answered just b, but i got it marked wrong so i am unsure. any thoughts?

because when the ball reached maximum height, the ball stops and then changes direction, so then it would have v=0 and the top. but would the speed be 0 as well?

You tell me. What's the relationship between speed and velocity?

velocity has to have direction while speed does not.

stephi said:
velocity has to have direction while speed does not.
Good. Speed is just the magnitude of the velocity. So how would you revise your first answer?

both speed and velocity will be zero?! :)

stephi said:
both speed and velocity will be zero?! :)
Of course.

thank you so much!
is there any chance you could also help me with a math problem that is giving me lots of trouble?

stephi said:
is there any chance you could also help me with a math problem that is giving me lots of trouble?
Did you post it?

yes but no replies yet,.

## 1. What is the initial velocity of the ball when thrown vertically in the air?

The initial velocity of the ball when thrown vertically in the air is the speed at which it is thrown upwards. This velocity is dependent on the force applied by the person throwing the ball and the mass of the ball itself.

## 2. What is the maximum height the ball can reach when thrown vertically in the air?

The maximum height the ball can reach when thrown vertically in the air is determined by the initial velocity and acceleration due to gravity. At the highest point, the velocity of the ball will be zero before it starts to fall back down.

## 3. How long does it take for the ball to reach its maximum height when thrown vertically in the air?

The time it takes for the ball to reach its maximum height when thrown vertically in the air is dependent on the initial velocity and acceleration due to gravity. It can be calculated using the formula t = v/g, where t is time, v is initial velocity, and g is the acceleration due to gravity.

## 4. What is the acceleration of the ball when thrown vertically in the air?

The acceleration of the ball when thrown vertically in the air is due to the force of gravity pulling it downwards. This acceleration is constant and is equal to 9.8 m/s^2 on Earth.

## 5. What is the final velocity of the ball when it hits the ground after being thrown vertically in the air?

The final velocity of the ball when it hits the ground after being thrown vertically in the air is dependent on the initial velocity and the distance it has fallen. It can be calculated using the formula v^2 = u^2 + 2as, where v is final velocity, u is initial velocity, a is acceleration due to gravity, and s is the distance fallen.