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
garik1379 [7]
3 years ago
13

A student (m = 68 kg) falls freely from rest and strikes the ground. During the collision with the ground, he comes to rest in a

time of 0.04 s. The average force exerted on him by the ground is +18000 N, where the upward direction is taken to be the positive direction. From what height did the student fall? Assume that the only force acting on him during the collision is that due to the ground.
Physics
1 answer:
Gnesinka [82]3 years ago
5 0

Answer:

5.7141 m

Explanation:

Here the potential and kinetic energy will balance each other

mgh=\frac{1}{2}mv^2\\\Rightarrow v=\sqrt{2gh}

This is the initial velocity of the system and the final velocity is 0

t = Time taken = 0.04 seconds

F = Force = 18000 N

a = Acceleration

g = Acceleration due to gravity = 9.81 m/s²

Equation of motion

v=u+at\\\Rightarrow a=\frac{v-u}{t}

From Newton's second law

F=ma\\\Rightarrow F=m\frac{v-u}{t}\\\Rightarrow 18000=68\frac{0-\sqrt{2gh}}{0.04}\\\Rightarrow \frac{18000}{68}\times 0.04=-\sqrt{2\times 9.81\times h}\\\Rightarrow 10.58823=-\sqrt{2\times 9.81\times h}

Squarring both sides

112.11061=2\times 9.81\times h\\\Rightarrow h=\frac{112.11061}{2\times 9.81}\\\Rightarrow h=5.7141\ m

The height from which the student fell is 5.7141 m

You might be interested in
What would you do to increase resistance
ratelena [41]

Answer:

If this is electrical currents , make the wire longer, smaller diameter wires, heat it up

6 0
3 years ago
Read 2 more answers
Please help me with this question :
aalyn [17]

Answer:

  • 514.27 ( wavelength )

the color is green

  • 602.93 nm  ( orange color )

the observation is that there is a change of visible color

Explanation:

A) wavelength of visible light that is most strongly reflected from a point on a soap

refraction n = 1.33

wall thickness (t) = 290 nm

2nt = (2m +1 ) ∝/2 -----equation 1

note when m = 0

therefore ∝ =  4nt/ 1 = 4 * 1.33 * 290 = 1542.8nm we will discard this

when m = 1

equation 1 becomes

∝ = 4nt/3 =( 4 * 1.33 * 290) /  3 = 1542.8 / 3 = 514.27 ( wavelength )

the color is green

B) the wavelength when the wall thickness is 340 nm

∝ = 4nt / 2m +1

where m = 1

∝ = (4 * 1.33 * 340 ) / 3  = 1808.8 / 3 = 602.93 nm  ( orange color )

the observation is that there is a change of visible color

7 0
3 years ago
Which best symbolizes the hydrogen bonding between two water molecules?
Artemon [7]

The best symbolizes the hydrogen bonding between two water molecules is given in the diagram.

<h3 /><h3>What is hydrogen bonding?</h3>

A hydrogen bond is an attraction between an electronegative atom carrying a single pair of electrons—the hydrogen bond acceptor—and a hydrogen atom that is covalently bonded to a more electronegative "donor" atom or group.

One definition of a polar covalent bond is one in which one atom has a stronger alternation for electron negativity difference between two bonds, the more polar the link.

Polar molecules like H2O have a mild partial negative charge in one area and a partial positive charge in another.

to learn more about hydrogen bond go to -

brainly.com/question/1426421

#SPJ4

4 0
2 years ago
Conservation equations are powerful equations, because of how versatile and flexible they are to different physical situations.
Temka [501]

Answer:

b) false

Explanation:

Since in the given situation it is mentioned that the mass conversation would be simple and same applied to the fluids with care also the conservation of momentum would be applied to any type of closed system like collisions

But as we know that

In the inelastic collisions, the total kinetic energy would not be remain conserved

So the given statement is false

8 0
3 years ago
A charge Q is uniformly spread over one surface of a very large nonconducting square elastic sheet having sides of length d. At
GuDViN [60]

Answer:

E/4

Explanation:

The formula for electric field of a very large (essentially infinitely large) plane of charge is given by:

E = σ/(2ε₀)

Where;

E is the electric field

σ is the surface charge density

ε₀ is the electric constant.

Formula to calculate σ is;

σ = Q/A

Where;

Q is the total charge of the sheet

A is the sheet's area.

We are told the elastic sheet is a square with a side length as d, thus ;

A = d²

So;

σ = Q/d²

Putting Q/d² for σ in the electric field equation to obtain;

E = Q/(2ε₀d²)

Now, we can see that E is inversely proportional to the square of d i.e.

E ∝ 1/d²

The electric field at P has some magnitude E. We now double the side length of the sheet to 2L while keeping the same amount of charge Q distributed over the sheet.

From the relationship of E with d, the magnitude of electric field at P will now have a quarter of its original magnitude which is;

E_new = E/4

3 0
3 years ago
Other questions:
  • What are 2 important statements about physical properties?
    9·1 answer
  • A 4-m long wire with a mass of 70 g is under tension. A transverse wave for which the frequency is 300 Hz, the wavelength is 0.6
    7·1 answer
  • A cyclist is traveling at 10m/s when he comes to a hill. He stops pedaling at the bottom of the hill and lets the bicycle coast
    11·1 answer
  • How much potential energy does a 20-kg barrel have when it is in the truck whose floor is 5.0 m above the ground? P.E. = J
    7·1 answer
  • A circuit with which components has a current with the greatest voltage?
    10·2 answers
  • How many cups are in 4 gallons
    9·1 answer
  • What is the mass of 2830 Newton's on Earth?
    6·1 answer
  • a car decelerates at a rate of 2.0 m/s^2 and comes to a complete stop after traveling 25 m. What was the speed of the car right
    6·1 answer
  • "Chief accelerator" is an American idiom. The term "communist virus" must also have come from the United States. Since the outbr
    9·1 answer
  • To perform a drug lookup to ensure that the new compound has been added to the computer system properly , select in the toolbar
    14·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!