# Physics: vertical motion and velocity/kinematics

## Homework Statement

In the attached file

## Homework Equations

Kinematics equations.

## The Attempt at a Solution

The question asks about vertical component. Isn’t this always 0? Like in C the intial velocity is the horizontal velocity but the vertical one is 0. Same applies to all. Am I correct?

#### Attachments

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## Answers and Replies

lewando
Homework Helper
Gold Member
The question asks about vertical component.
...at the point of impact with the ground.

Isn’t this always 0?
No.
in C the initial velocity is the horizontal velocity but the vertical one is 0.
Yes.
Same applies to all. Am I correct?
No.

...at the point of impact with the ground.

No.

Yes.

No.
Could not understand ‘ at the point of impact with the ground ‘

And why E is wrong?

lewando
Homework Helper
Gold Member
When you throw a ball off a tower it will eventually "hit the ground". The question is directly asking for the downward (vertical) component velocity at the moment the ball "strikes the ground". To be even more clear, this "moment" is actually the time right before the ball starts interacting with the ground.

When you throw a ball off a tower it will eventually "hit the ground". The question is directly asking for the downward (vertical) component velocity at the moment the ball "strikes the ground". To be even more clear, this "moment" is actually the time right before the ball starts interacting with the ground.
Final velocity, then?

lewando
Homework Helper
Gold Member
Yes final velocity--at the time right before the ball begins to interact with the ground.

Yes final velocity--at the time right before the ball begins to interact with the ground.

Should I use the equation Vf=Vi+gt? Where Vi is 0 in C, but how should I check the other choices

lewando
Homework Helper
Gold Member
Should I use the equation Vf=Vi+gt? Where Vi is 0 in C, but how should I check the other choices
This is more of a concept question, you should be able to arrive at an answer by thinking about it. So try thinking about it. And if you want to verify your thought process, go ahead and assign a tower height and specific values for initial velocity components see what results you get.

By the way, in post #5, that should be "final vertical velocity"

• YMMMA
This is more of a concept question, you should be able to arrive at an answer by thinking about it. So try thinking about it. And if you want to verify your thought process, go ahead and assign a tower height and specific values for initial velocity components see what results you get.

By the way, in post #5, that should be "final vertical velocity"
Okay, thank you!