Skip to main content
M

One physics question about work/change in energy?

Harold the Hurler is a physics student who is renowned for his baseball pitching arm. In order to determine the amount of work he performs in throwing a baseball, Harold devises an experiment. He stands at the bottom of a deep pit and hurls a 147-g baseball through an open third-floor window in a nearby building. Harold’s aim is so accurate that the ball then smoothly enters the tube of the Baseball Absorber that Harold invented and patented. In this device the ball compresses a spring until it comes momentarily to rest, and this maximum amount of compression is recorded as 41.9 cm. The spring’s force constant is 837 N/m, and the position of the baseball’s momentary rest is 7.87 m above ground level. The point in the pit where the Hurler starts his pitch is 11.1 m below ground level. How much work does Harold perform on the baseball? Take g = 9.80 m/s2.
0
Save

2 Answers

E
Everardo Feil

Feb 20, 2025

There are two places where the energy (work) that has been imparted to the baseball has been stored – in gravitational potential energy (mgh) and in the potential energy of the spring (½kx²). gravitational potential energy:m = 0.147 kgg = 9.8 m/s²h = 7.87m + 11.1m = 18.97mmgh = 27.3 J potential energy of the spring:k = 837 N/mx = 0.419 m½kx² = 73.5 JTotal stored energy when ball comes to rest = 100.8 JTotal work performed on the baseball (assuming zero loss to atmospheric friction) =100.8 JAs a sanity check, the pitch speed is given here by the kinetic energy: 100.8 = ½mv², which rearranges to v = √(100.8 * 2 / m), where m = 0.147 kg. This gives v = 37 m/s, or 83 mph. That’s a long way from record-breaking, but better than I could do!... Show More
0

Want to answer this question?

Join our community to share your knowledge!

Log in Sign up

Categories

Tags

Related Questions

6
One possible reason that the revolutionary-era poets used the

One possible reason that the revolutionary-era poets used the a. trochaic b. spondaic c. iambic d. anapestic meter was t...

3
One potential drawback of using social media in the workplace is that social media

One potential drawback of using social media in the workplace is that social media

4
One process catalyzed by nadh dehydrogenase is nadh + h + + ubiquinone − ⇀ ↽ − nad + + ubiquinol

One process catalyzed by nadh dehydrogenase is nadh + h + + ubiquinone − ⇀ ↽ − nad + + ubiquinol

10
One way an author uses direct characterization is by telling the reader about the character through

ооo what the character says.what the narrator says.O what the character does.O what the narrator does.

6
One way to get consistent, valid data is to

One way to get consistent, valid data is to

8
Onida TV – how do I unlock child lock – Default password is not working?

I think by mistake by daughter has activated child lock – I now get a screen asking a password when I switch on the TV –...

4
Online German shoe store?

I recently visited a website that had some really cute shoes I was interested in but I totally forgot to write it down a...

10
Only one of my armpits have a bad odor, why is this?

I know it sounds crazy, but I never had a problem with body odor until now. Only one of my armpits has a bad odor and I...

4
Only six elements make up 99% of the human body’s mass. the six elements are a. carbon, oxygen, hydrogen, nitrogen, calcium, and sodium.

Only six elements make up 99% of the human body's mass. the six elements are a. carbon, oxygen, hydrogen, nitrogen, calc...

2
Only true historians can figure this out!?

1) The Wisconsin Idea refers to reforms that, among other things, A) called for direct ellections B) abolished convict l...