# Physics problem help please!

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A rock is thrown upwards with a velocity of 6.0 m/s. What is the maximum height it will reach?

Please help, I have no idea how to do it! And its on earth.

Please help, I have no idea how to do it! And its on earth.

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#2

(Original post by

A rock is thrown upwards with a velocity of 6.0 m/s. What is the maximum height it will reach?

Please help, I have no idea how to do it! And its on earth.

**pheonixfeather**)A rock is thrown upwards with a velocity of 6.0 m/s. What is the maximum height it will reach?

Please help, I have no idea how to do it! And its on earth.

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(Original post by

Do you know the SUVAT equations?

**Benniboi1**)Do you know the SUVAT equations?

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#5

(Original post by

I dont think so...

**pheonixfeather**)I dont think so...

Use the fact that all the E

_{k}will be converted to gravitational potential.

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(Original post by

You know how much kinetic energy it has, right?

Use the fact that all the E

**alow**)You know how much kinetic energy it has, right?

Use the fact that all the E

_{k}will be converted to gravitational potential.Posted from TSR Mobile

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#7

**pheonixfeather**)

But the only numbers it gives you is the velocity and the gravity so how are you supposed to get the kinetic energy?

Posted from TSR Mobile

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#9

(Original post by

that doesn't help, I know those equations. Could you show me how you'd do it please?

**pheonixfeather**)that doesn't help, I know those equations. Could you show me how you'd do it please?

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#10

(Original post by

I dont think so...

**pheonixfeather**)I dont think so...

(1) v = u + at

(2) s = ut + 0.5at^2

(3) v^2 = u^2 +2as

(4) s = 0.5(u + v)t

(5) s= vt - 0.5at^2

You can use the SUVAT equations if you know 2/3 variables and need to find out the others. In your question, we know initial velocity is 6 m/s, we also know acceleration due to gravity on earth is -9.8m/s (the minus sign is important for this example!).

When you throw the rock up and it reaches it's max height before coming down, what is the velocity of the rock at that point?

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#11

(Original post by

So the SUVAT equations involve 5 variables: displacement (S), initial velocity (U), final velocity (V), acceleration (A) and time (T). They are:

(1) v = u + at

(2) s = ut + 0.5at^2

(3) v^2 = u^2 +2as

(4) s = 0.5(u + v)t

(5) s= vt - 0.5at^2

You can use the SUVAT equations if you know 2/3 variables and need to find out the others. In your question, we know initial velocity is 6 m/s, we also know acceleration due to gravity on earth is -9.8m/s (the minus sign is important for this example!).

When you throw the rock up and it reaches it's max height before coming down, what is the velocity of the rock at that point?

**Benniboi1**)So the SUVAT equations involve 5 variables: displacement (S), initial velocity (U), final velocity (V), acceleration (A) and time (T). They are:

(1) v = u + at

(2) s = ut + 0.5at^2

(3) v^2 = u^2 +2as

(4) s = 0.5(u + v)t

(5) s= vt - 0.5at^2

You can use the SUVAT equations if you know 2/3 variables and need to find out the others. In your question, we know initial velocity is 6 m/s, we also know acceleration due to gravity on earth is -9.8m/s (the minus sign is important for this example!).

When you throw the rock up and it reaches it's max height before coming down, what is the velocity of the rock at that point?

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#12

**pheonixfeather**)

that doesn't help, I know those equations. Could you show me how you'd do it please?

You've been given plenty of help but appear to want someone else to do this for you.

In that equation m cancels on both sides.

You have v and g in the question, so find h. (Or delta h as it appears in the one posted)

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#13

(Original post by

There's no need to use SUVATs, and just stating them without derivation isn't really giving any understanding.

**alow**)There's no need to use SUVATs, and just stating them without derivation isn't really giving any understanding.

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#14

You have two options. (1/2)mv^2 = mgh so (1/2)v^2 = gh

Rearranging, you get h = v^2/2g so you can work it out that way.

Using suvat, you want s, have u, v and a and don't need t. The equation is v^2 = u^2 + 2as.

Rearranging, you get s = (v^2 - u^2)/2a. As v^2 = 0 this simplifies to exactly what you have above, just with different letters.

Rearranging, you get h = v^2/2g so you can work it out that way.

Using suvat, you want s, have u, v and a and don't need t. The equation is v^2 = u^2 + 2as.

Rearranging, you get s = (v^2 - u^2)/2a. As v^2 = 0 this simplifies to exactly what you have above, just with different letters.

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(Original post by

You have two options. (1/2)mv^2 = mgh so (1/2)v^2 = gh

Rearranging, you get h = v^2/2g so you can work it out that way.

Using suvat, you want s, have u, v and a and don't need t. The equation is v^2 = u^2 + 2as.

Rearranging, you get s = (v^2 - u^2)/2a. As v^2 = 0 this simplifies to exactly what you have above, just with different letters.

**dangerworm**)You have two options. (1/2)mv^2 = mgh so (1/2)v^2 = gh

Rearranging, you get h = v^2/2g so you can work it out that way.

Using suvat, you want s, have u, v and a and don't need t. The equation is v^2 = u^2 + 2as.

Rearranging, you get s = (v^2 - u^2)/2a. As v^2 = 0 this simplifies to exactly what you have above, just with different letters.

Posted from TSR Mobile

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(Original post by

What do you mean, that doesn't help?

You've been given plenty of help but appear to want someone else to do this for you.

In that equation m cancels on both sides.

You have v and g in the question, so find h. (Or delta h as it appears in the one posted)

**Stonebridge**)What do you mean, that doesn't help?

You've been given plenty of help but appear to want someone else to do this for you.

In that equation m cancels on both sides.

You have v and g in the question, so find h. (Or delta h as it appears in the one posted)

Posted from TSR Mobile

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#17

(Original post by

You seem to misundersand, what I did want was someone to explain it in terms that I would understamd. You seem to be forgetting that not everybody is a genius and can figure out how to do something by information they already know when they were stuck with that knowledge in the first place.

Posted from TSR Mobile

**pheonixfeather**)You seem to misundersand, what I did want was someone to explain it in terms that I would understamd. You seem to be forgetting that not everybody is a genius and can figure out how to do something by information they already know when they were stuck with that knowledge in the first place.

Posted from TSR Mobile

You implied this in one of your answers.

If that is the case then you needed to do this via energy considerations.

Your first post stated that you had "no idea" how to start.

So by the time I posted you had been given the energy formula to use, which you then said didn't help.

In what sense did it not help?

I told you to cancel the m and find h from the values left.

What more did you need?

You only needed to rearrange the formula and plug in the numbers.

To claim that we are expecting you to be a genius to do this is to miss the point of this forum and to turn your nose up at the help that

**was**offered.

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#18

Maybe watching a video with some examples may help

https://www.youtube.com/watch?v=JIUmt7Z_7p4

There are a few to watch and helped me a lot

https://www.youtube.com/watch?v=JIUmt7Z_7p4

There are a few to watch and helped me a lot

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(Original post by

So are you saying you haven't studied the so called SUVAT equations?

You implied this in one of your answers.

If that is the case then you needed to do this via energy considerations.

Your first post stated that you had "no idea" how to start.

So by the time I posted you had been given the energy formula to use, which you then said didn't help.

In what sense did it not help?

I told you to cancel the m and find h from the values left.

What more did you need?

You only needed to rearrange the formula and plug in the numbers.

To claim that we are expecting you to be a genius to do this is to miss the point of this forum and to turn your nose up at the help that

**Stonebridge**)So are you saying you haven't studied the so called SUVAT equations?

You implied this in one of your answers.

If that is the case then you needed to do this via energy considerations.

Your first post stated that you had "no idea" how to start.

So by the time I posted you had been given the energy formula to use, which you then said didn't help.

In what sense did it not help?

I told you to cancel the m and find h from the values left.

What more did you need?

You only needed to rearrange the formula and plug in the numbers.

To claim that we are expecting you to be a genius to do this is to miss the point of this forum and to turn your nose up at the help that

**was**offered.
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#20

**pheonixfeather**)

A rock is thrown upwards with a velocity of 6.0 m/s. What is the maximum height it will reach?

Please help, I have no idea how to do it! And its on earth.

u= -6 m/s ( taking upward motion as negative)

v= 0 m/s (as the rock's velocity becomes zero after reaching full height)

g= 9.81 m/s^2

h=?

Using equation,

v^2 = u^2 + 2gh

0 = (-6)^2 + (2 x 9.81) h

19.62 h = -36

so, h = - 1.83 m

As this is a negative value and height or distance simply can't be negative on their own, this means the maximum distance or height reached upward is 1.83m.

I hoe this helps a bit!

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