+0

# If a ball is dropped, how long must it fall to attain a velocity of 12.55m/s?

0
370
4

If a ball is dropped, how long must it fall to attain a velocity of 12.55m/s?

Guest Mar 22, 2015

### Best Answer

#3
+94120
+10

I shall show you the calculus solution

$$\\\ddot{y}=9.8\\\\ \dot{y}=9.8t+c\\\\ when \;\;t=0\;\;\dot{y}=0\;\;so\;\;c=0\\\\ \dot{y}=9.8t\\\\ Find t when \;\dot{y}=12.55\\\\ 12.55=9.8t\\\\ t=\frac{12.55}{9.8}=1.28sec$$

There you go - that was pretty simple too.  :)

Melody  Mar 23, 2015
#1
+94120
+10

did you need to use physics formula or calculus?

If a ball is dropped, how long must it fall to attain a velocity of 12.55m/s?

I will assume that you are on Earth near seal level      gravity=9.8m/s^2

a=9.8,   u=0,   v=12.55,   t=?

v=u+at

12.55=0+9.8*t

12.55=9.8t

$${\frac{{\mathtt{12.55}}}{{\mathtt{9.8}}}} = {\frac{{\mathtt{251}}}{{\mathtt{196}}}} = {\mathtt{1.280\: \!612\: \!244\: \!897\: \!959\: \!2}}$$

1.28 seconds

If you need to use calc you can ask and it shall be done.

Melody  Mar 23, 2015
#2
+92808
+5

That linear formula looks pretty straight forward to me, Melody......

Is it more confusing with calculus???

CPhill  Mar 23, 2015
#3
+94120
+10
Best Answer

I shall show you the calculus solution

$$\\\ddot{y}=9.8\\\\ \dot{y}=9.8t+c\\\\ when \;\;t=0\;\;\dot{y}=0\;\;so\;\;c=0\\\\ \dot{y}=9.8t\\\\ Find t when \;\dot{y}=12.55\\\\ 12.55=9.8t\\\\ t=\frac{12.55}{9.8}=1.28sec$$

There you go - that was pretty simple too.  :)

Melody  Mar 23, 2015
#4
+92808
0

Yep...equally easy......

CPhill  Mar 23, 2015

### New Privacy Policy

We use cookies to personalise content and advertisements and to analyse access to our website. Furthermore, our partners for online advertising receive information about your use of our website.
For more information: our cookie policy and privacy policy.