# Homework Help: Solve Physics & Math Problems with Answers

• Stephanie
In summary, the minimum height H from which the mass m must be released in order to remain on the track at the top of the circle is 2.5 times the radius of the circle.71. A paratrooper with a mass of 80kg fell 370m after jumping from an aircraft without his parachute opening. Upon landing, he created a crater 1.1m deep and survived with minor injuries. Assuming his terminal velocity was 30m/s, the work done on him by air resistance during the fall can be estimated as 88800 Joules.In summary, the work done on the paratrooper by air resistance during his fall was 88800 Joules.74. In a film of Jesse Owens
Stephanie
I've tried these problems but I need some help.

44. a small mass m slides without fritction around the looped apparatus show in the picture below. If the object is to remain on the track, even at the top of the circle (whose radius is r), from what minimum height H must it be released?

http://i75.photobucket.com/albums/i319/Thepalaceguild/draw.jpg

71. A paratrooper fell 370m after jumping from an aircraft without his parachute opening. He landed in a snowback, creating a crater 1.1m deep, but survived with only minor injuries. Assuming the paratroopers mass was 80kg and his terminal velocity was 30m/s, estimate the work done on him by air resistance as he fell.

74. In a film of Jesse Owens's famous long jump in the 1936 Olympics, it is observed that his center of mass rose 1.1m from launch point to the top of the arc. What minimum speed did he need at launch if he was also noted to be traveling at 6.5m/s at the top of the arc?

76. A ball is attached to a horizontal cord of length L, whose other end is fixed, (picture below). (a) If the ball is released, what will be its speed at the lowest point of its path?(b)A peg is located a distance H directly below the point of attachment of the cord. If H=.8L, what will be the speed of the ball when it reaches the top of its circular path about the peg?

http://i75.photobucket.com/albums/i319/Thepalaceguild/draw2.jpg

81. Water flows over a dam at the rate of 550 Kg/s and falls vertically 80m before striking the turbine blades. Calculate: the rate at which mechanical energy is transferred to the turbine blades, assuming 60% efficiency.

85. A 75Kg student runs at 5.0 m/s, grabs a rope, and swings out over a lake. He releases the rope when is velocity is zero. (a) What is the angle (-)(theta) when he releases the rope? (b) What is the tension in the rope just before he releases it? (c) What is the maximum tention in the rope?

Thanks to all who respond. ^_^

Last edited by a moderator:
Stephanie said:
I've tried these problems but I need some help.

Well, if you're stuck somewhere, you could perhaps point out where the problem is.

44.
N + mg = mv^2 /r -at the top of the loop
N goes to zero and
mg = (mv^2)/r

so v minimum = √rg

now use energy conservation
mgh + 0 = 0.5m(√rg)^2
h = 0.5r

and your H = 2r+ h = 2.5*r

## 1. What kind of physics and math problems can I get help with?

Our homework help service can assist with a wide range of physics and math problems, including algebra, calculus, mechanics, electricity and magnetism, thermodynamics, and more.

## 2. How do I submit my problem for help?

You can submit your problem by clicking on the "Submit a Problem" button on our website and filling out the form with your problem and any relevant information. You can also email us directly with your problem.

## 3. How long does it take to get an answer?

Our team of experts works diligently to provide quick and accurate solutions to all problems. Typically, you can expect to receive an answer within 24 hours.

## 4. Can I get step-by-step explanations for the solutions?

Yes, our experts not only provide the answer to your problem, but they also provide detailed step-by-step explanations to help you understand the solution and improve your understanding of the subject.

## 5. Is this service free?

No, our homework help service is not free. We have a team of experienced and qualified experts who work hard to provide high-quality solutions to your problems. However, we offer competitive and affordable pricing options for our services.

• Introductory Physics Homework Help
Replies
1
Views
5K
• Introductory Physics Homework Help
Replies
1
Views
1K
• Introductory Physics Homework Help
Replies
6
Views
3K
• Introductory Physics Homework Help
Replies
12
Views
2K
• Introductory Physics Homework Help
Replies
4
Views
3K
• Introductory Physics Homework Help
Replies
8
Views
4K
• Introductory Physics Homework Help
Replies
4
Views
2K
• Introductory Physics Homework Help
Replies
21
Views
9K
• Introductory Physics Homework Help
Replies
4
Views
4K
• Introductory Physics Homework Help
Replies
5
Views
1K