1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Scorpion4ik [409]
3 years ago
6

In the vertical jump, an athlete starts from a crouch and jumps upward as high as possible. Even the best athletes spend little

more than 1.00 s in the air (their "hang time"). Treat the athlete as a particle and let ymax be his maximum height above the floor. To explain why he seems to hang in the air, calculate the ratio of the time he is above ymax/2 to the time it takes him to go from the floor to that height. Ignore air resistance.
Physics
1 answer:
horrorfan [7]3 years ago
8 0

Answer:

t_up / t_down = 6.83

Explanation:

Find:

Calculate the ratio of the time he is above y_max/2 to the time it takes him to go from the floor to that height.

Solution:

- Compute the velocity v_o at y_max:

                             v_i^2 = v_f^2 - 2*g*y_max

                             0 = v_o^2 - 2*g*y_max

                             v_o = sqrt (2*g*y_max)

- The total time spend by athlete above height y_max / 2 is:

                             y - y_o = v_o*t_up - 0.5*g*t^2_up

                             v_o = 0.5*g*t_up

- Equate two equations:

                             sqrt (2*g*y_max) = 0.5*g*t_up

                             t_up = 2*sqrt(2*g*y_max) / g

- The total time taken by athlete to reach height y_max / 2 from ground is:

                            y - y_o = v_o*t_down - 0.5*g*t^2_down

                            g*t_^2down - 2*v_o*t_down + y_max = 0

- Solve the quadratic and evaluate t_down:

                            t_down = (v_o +/- sqrt (v^2_o - g*y_max)) / g

Substitute for v_o =  sqrt (2*g*y_max)

                            t_down = (sqrt(2g*y_max) +/- sqrt(g*y_max)) / g

- We will use the minus quantity, because we need the first part of the journey from ground from the two times he passes the height of y_max/2.

Hence,

                             t_down = (sqrt(2g*y_max) - sqrt(g*y_max)) / g

                             t_down = (sqrt(g*y_max) / g) * (sqrt(2) - 1)

- Compute the ratio t_up to t_down:

         t_up / t_down = 2*sqrt(2*g*y_max) / g * g / (sqrt(g*y_max)*(sqrt(2) - 1)

                                  = 2*sqrt(2) / (sqrt(2) - 1)

                                  = 6.83

You might be interested in
The second-order decomposition of hi has a rate constant of 1.80 x 10−3 m−1 s−1. How much hi remains after 45.6 s if the initial
zlopas [31]

Answer:

2.9 M

Explanation:

The concentration-time equation for a second order reaction is:

1/[A] = kt + 1/[A°]

Where,

A = concentration remaining at time, t

A° = initial concentration

k = rate constant

1/[A] = (1.80 x 10^-3) * (45.6) + 1/3.81

1/[A] = 0.345

= 1/0.345

= 2.9 M.

6 0
3 years ago
True or false, both mass spectrometry and infrared spectroscopy involve the interaction of molecules with electromagnetic energy
zavuch27 [327]
Yes, it is true, both mass spectrometry and infrared spectroscopy involve interaction of molecules with electromagnetic waves. ;Mass spectrometry method is used to determine the mass of a substance while infrared spectroscopy is used to determine the functional groups in molecules. Both methods involve the analysis of electromagnetic light interaction with molecules. 
7 0
3 years ago
Is an example of a physical process that a physical geographer would study.
diamong [38]
D. The environment
Is the right answer
8 0
3 years ago
What is the name of the person that help people at the gym?
frozen [14]

That is called a physical trainer or a fitness coach. Hope I helped!

5 0
3 years ago
Read 2 more answers
What is the distance a truck can travel if it moves 7 m/s for 20 seconds?
artcher [175]

if it moves 7m/s, that means every second it goes 7m.  Now we just multiply by the time (20 seconds) and end up with 140m.

6 0
3 years ago
Read 2 more answers
Other questions:
  • In a stadium, fans stand up and sit down to produce a wave across the stadium. This type of wave where the material travels perp
    5·2 answers
  • Is Newton's third law of motion relevant to dropping an egg
    13·1 answer
  • A substance that does not react with metal, has a bitter taste, and turns litmus paper blue is a(n) ___.
    9·1 answer
  • A relief airplane is delivering a food package to a group of people stranded on a very small island. The island is too small for
    10·1 answer
  • An electron is moving east in a uniform electric field of 1.55 N/C directed to the west. At point A, the velocity of the electro
    11·1 answer
  • A factory worker pushes a 31.0 kg crate a distance of 4.20 m along a level floor by pushing downward at an angle of 32.0 ∘ below
    15·1 answer
  • ფიზიკაში მჭირდება დახმარება ნაგლმა მასწავლებელმა მთელი თვე გააცდინა და როცა დაბრუნდა ეგრევე საკონტროლო ისეთი საკითხებით რომელიც
    6·1 answer
  • A student lists a set of materials
    7·1 answer
  • What is the velocity of a group of explorers traveling from Antarctica to Australia, traveling 1500 miles in 48 hours?31.25 mph
    15·1 answer
  • What are some common positive and negative attitudes toward physical activities? What
    11·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!