Solve Jumper Question Homework: Part A & B with Initial Speed & Force

  • Thread starter dkirov1
  • Start date
In summary, the person reaches a maximum height of 64 cm when jumping straight up from a crouched position. The body from the knees up rises a distance of 41 cm during the jump. To find the initial speed in Part A, the formula Egmax=Ekmax was used and the velocity was found to be 3.5. In Part B, the force exerted by the ground on the person was calculated using the formula F=ma, where F is the force, m is the person's weight, and a is the acceleration. The final velocity from Part A was used to solve for the acceleration, and the force was found to be Wg, where W is the person's weight and g is the acceleration
  • #1
dkirov1
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Homework Statement



A person reaches a maximum height of 64 cm when jumping straight up from a crouched position. During the jump itself, the person's body from the knees up rises a distance of around 41 cm. To keep the calculations simple and yet get a reasonable result, assume that the entire body rises this much during the jump.

Part A: With what initial speed does the person leave the ground to reach a height of 64 cm?
Part B: In terms of this jumper's weight W , what force does the ground exert on him or her during the jump?

I figured out the first part, but I can't figure out the second part. :(

Also the answer to part B has to be a number? This is online homework and the answer is in the format:

F=_____W


Homework Equations



F=ma


The Attempt at a Solution


The velocity for part A was 3.5
I tried to figure out the time by using v=d/t, and got t=.117 seconds which seems wrong.
I tried to figure out the a so I used vf-vo/t=29.91?
and using 29.91 as a tried to figure it out. But I'm just stuck. I have no idea.
 
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  • #2
The force the ground exerts on the person is going to last 41 cm, the initial velocity would be 0, the final velocity would be the answer to part a, from there you can solve for acceleration.
 
  • #3
A very simple way to solve this, assuming this is a closed system, would be to use the attached formula (Egmax=Ekmax); rearrange algebraically. I would assume the force the ground exerts on her would be gravity, so F is mg or F=Wg.

Hope this helps.
 

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What is the purpose of "Solve Jumper Question Homework: Part A & B with Initial Speed & Force"?

The purpose of this assignment is to apply the principles of physics, specifically Newton's laws of motion, to solve a real-world problem involving a jumping athlete. By determining the initial speed and force required for the athlete to successfully complete the jump, students will gain a deeper understanding of the concepts and equations involved in calculating motion.

What are the key concepts involved in solving this homework?

The key concepts involved in solving this homework include Newton's laws of motion, specifically the laws of inertia, acceleration, and action and reaction. Other important concepts include work, energy, and power, as well as equations such as the work-energy theorem and the kinematic equations.

What are the steps involved in solving this homework?

The first step is to clearly define the problem and identify the known and unknown variables. Then, students should apply the appropriate equations and principles to calculate the initial speed and force needed for the jump. Next, students should double check their calculations and make any necessary adjustments. Finally, the results should be presented clearly and explained in the context of the problem.

What are some common mistakes students make when solving this homework?

One common mistake is not properly identifying and labeling the known and unknown variables. Another mistake is not using the correct equations or applying them incorrectly. It is also important to pay attention to units and conversions. Finally, students may also make mistakes in their calculations or rounding errors.

How can this homework assignment be applied to real-world situations?

The concepts and skills used in this homework, such as calculating motion and forces, are applicable to many real-world situations. For example, understanding the initial speed and force required for a jump can be useful in sports training and performance. Additionally, the principles of motion and forces are essential in fields such as engineering, architecture, and transportation.

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