## De Broglie Problem

$\lambda=\frac{h}{p}$

Doreen Liu 4D
Posts: 54
Joined: Wed Sep 11, 2019 12:17 am

### De Broglie Problem

A baseball must weigh between 5 and 5.25 ounces. What is the wavelength of a 5.15 ounce ball thrown at 92mph.
Can someone help me with this problem? Also, would I have to turn both the ounces and the miles/hour into SI units before I can start solving it?

Mansi_1D
Posts: 50
Joined: Fri Aug 02, 2019 12:15 am

### Re: De Broglie Problem

To find the wavelength, you would use h/mv equation. The mass is 5.15 ounce and velocity is 92mph. However, the mass has to be in kg and the velocity in m/s when you plug it into the equation, so yes you would have to convert them first.

Ananta3G
Posts: 62
Joined: Wed Sep 18, 2019 12:19 am

### Re: De Broglie Problem

The equation gives you an answer in meters so you would need to convert the velocity from mph to m/s first. Then, in order for Planck's constant's units, J/Hz to cancel out the other units, you need to convert the mass to Kg, otherwise you would have one mass in ounce but a unit that uses Kg which would stop the equation from working.

Ryan Chang 1C
Posts: 105
Joined: Sat Aug 24, 2019 12:17 am

### Re: De Broglie Problem

After converting the values, plugging in each value would look like this:

(6.626x10^-34 kg ms^2 s^-1)/(1.675x10^-27kg x 100x10^-12m) = 3.96x10^3m/s

Megan Jung 3A
Posts: 50
Joined: Thu Jul 11, 2019 12:17 am

### Re: De Broglie Problem

For this problem, you would have to convert oz to kg and mph to km/h

The conversion for oz to kg :
5.15oz(28.3g/10oz)(1kg/1000g)

The conversion for mph to km/h:
92mi/hr(1hr/3600sec)(1.609344km/mi)

From there, use De Broglie's Equation to solve for the wavelength