## Exercise 1.39 [ENDORSED]

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

Jacinda Wollenweber 1D
Posts: 22
Joined: Wed Nov 16, 2016 3:02 am

### Exercise 1.39

A baseball must weigh between 5.00 and 5.25 ounces (1 ounce = 28.3g). What is the wavelength of a 5.15-ounce baseball thrown at 92mph?
Can someone walk me through the steps please? Thanks!

Stephanie H
Posts: 20
Joined: Fri Jun 23, 2017 11:39 am

### Re: Exercise 1.39

1) convert 5.15 oz to grams, and 92mph to meters per second

2) once converted, use the De Broglie equation: wavelength=(h)/(mass*velocity)

3) then you will get your answer in meters, convert to nanometers just in case

CameronJohari1J
Posts: 66
Joined: Fri Sep 29, 2017 7:06 am
Been upvoted: 1 time

### Re: Exercise 1.39  [ENDORSED]

Quick reminder that once you convert ounces to grams, then grams must then be converted to kg, as SI units must be used to solve debroglie equation problems. The other SI unit in the problem is meters per second for velocity.

Michelle Nwufo 2G
Posts: 61
Joined: Fri May 18, 2018 3:00 am

### Re: Exercise 1.39

So, mass is always represented in kilograms and velocity in meters per second?

Bita Ghanei 1F
Posts: 60
Joined: Thu Feb 28, 2019 12:15 am

### Re: Exercise 1.39

Michelle Nwufo 2G wrote:So, mass is always represented in kilograms and velocity in meters per second?

I believe this only holds true for the De Broglie Equation

wavelength in meters,
h in Js,
mass in kg
velocity in m/s

Please correct me if I am wrong.