How High Does a Ball Go If Thrown Upwards at 40m/s?

  • Thread starter cyberhev
  • Start date
In summary, the height reached by a ball thrown vertically upwards with an initial velocity of 40m/s can be calculated by using the formula |V| = |g|*t, where V is the initial velocity and g is the acceleration due to gravity. By solving for time (t), one can then use the formula s = ut + 1/2at^2 to find the displacement (s) of the ball. It is important to note that in this equation, g should be written as -9.8 m/s^2, as it is an acceleration, not a velocity.
  • #1
cyberhev
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0

Homework Statement



Height reached by a ball if it is thrown vertically upwards with an initial velocity of 40m/s

Homework Equations



Using V^2=u^2+2as

The Attempt at a Solution

I have been told to ignore air resistance and let g =9.8 m/s. Any help anyone?
 
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  • #2
Well you have the correct equation. Just plug in all the variables and solve for the displacement s.
 
  • #3
Consider that the balls's velocity of 40 m/s is being sapped away by gravity at a rate of 9.8 m/s/s. How much time (t) will it take for v to be reduced to zero?

What will the ball's average velocity be over time period t? (Now you can solve for h.)

(Also: you probably just made a typo but note that g is an acceleration and as such takes the unit "m/s/s", normally written "m/s2". "m/s" is a unit of velocity, not acceleration.).
 
  • #4
Thank you! Yes it was a typo! I am right that even if this question states initial velocity is 40m/s the actual value of u in this question is zero? Also my transposition of this equation works out to be V^2-u^2 divided by 2a=s?
 
  • #5
Yes the final velocity is 0 for that equation.

So for your equation:

0 = 402 +2*(-g)*x

(if +X is up, then g carries a - sign.)

If time is all you want then you have an easier path with

|V| = |g|*t

t = V/g
 

1. What is the equation for transposing V^2=u^2+2as?

The equation for transposing V^2=u^2+2as is given by V = √(u^2+2as), where V is the final velocity, u is the initial velocity, a is the acceleration, and s is the displacement.

2. What does the equation V^2=u^2+2as represent?

The equation V^2=u^2+2as represents the relationship between velocity, acceleration, and displacement in a linear motion with constant acceleration. It is derived from the equations of motion and is commonly used in physics and engineering.

3. How do I use the equation V^2=u^2+2as to solve a problem?

To use the equation V^2=u^2+2as, you need to know the values of three variables: initial velocity (u), acceleration (a), and displacement (s). Plug in these values into the equation and solve for the final velocity (V). Make sure to use the appropriate units for each variable.

4. Can the equation V^2=u^2+2as be used for any type of motion?

No, the equation V^2=u^2+2as is only valid for linear motion with constant acceleration. It cannot be used for other types of motion, such as circular or projectile motion.

5. How does the equation V^2=u^2+2as relate to the concept of kinetic energy?

The equation V^2=u^2+2as can be derived from the equation for kinetic energy, which is given by K = ½mv^2, where m is the mass of the object and v is its final velocity. This shows that the final velocity (V) is directly related to the object's kinetic energy. Additionally, the term u^2 represents the initial kinetic energy, and 2as represents the work done by the acceleration on the object.

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