Answer:
a) a = 2000 g , b) y = 4 cm
Explanation:
a) We can solve this part using the free fall relations
Let's start by finding the speed with which it reaches the ground, just before it starts to decelerate
v₁² = v₀² + 2 g y
as it comes out of rest the initial velocity is v₀ = 0
v₁ = √ 2g y
v₁ = √ (2 9.8 2)
v₁ = 6.26 m / s
in the braking part the distance is y₂ = 1 mm = 0.001 m
v² = v₁² - 2 a y₂
when stopping its velocity is zero v = 0
a = v₁² / 2y₂
a = 6.26² / (2 0.001)
a = 1.96 10⁴ m / s²
This is the braking acceleration.
Let's look for its relationship with the acceleration of gravity
a / g = 1.96 10⁴ / 9.8
a / g = 2000
a = 2000 g
b) to reduce the injury to less than 25%, the maximum acceleration that must be a = 50g = 490 m / s²
Let's find the distance it must travel to have this acceleration
v² = v₁² - 2 a y
y = (0 + v₁²) / 2a
y = 6.26² / (2 490)
y = 0.04 m
y = 4 cm
therefore we must have a helmet that deforms 4 cm before the head stops
Most bicycle helmets provide this protection since they are quite elongated
c) The main error in the calculations is not taking into account the
resistance with the air, in this sense the speed would be less than the calculated one and our calculations would be over estimated.
The second factor is that in a fall there may be an initial velocity different from zero, so the velocity would be higher and the acceleration as well, in this case our calculations are underestimated.
An object increases its velocity from 20 m/s to 63 m/s in 10 s. What is the acceleration of the object?
Answer:
An object increases its velocity from 20 m/s to 63 m/s in 10 s. What is the acceleration of the object?
Explanation:
As a fish jumps vertically out of the water, assume that only two significant forces act on it: an upward force F exerted by the tail fin and the downward force due to gravity. A record Chinook salmon has a length of 1.50 m and a mass of 46.0 kg. If this fish is moving upward at 3.00 m/s as its head first breaks the surface and has an upward speed of 5.80 m/s after two-thirds of its length has left the surface, assume constant acceleration and determine the following.
a. The salmon's acceleration
b. The magnitude of the force F during this interval N
Answer:
a
[tex]a = 12.32 \ m/s^2[/tex]
b
[tex]F = 1017.52 \ N[/tex]
Explanation:
From the question we are told that
The length of the Chinook salmon is [tex]l = 1.50 \ m[/tex]
The mass of the Chinook salmon is [tex]m = 46.0 \ kg[/tex]
The upward velocity in water is [tex]u = 3.00 \ m/s[/tex]
The upward velocity in air is [tex]v = 5.80 \ m/s[/tex]
Generally from kinematic equations
[tex]v^2 = u^2 + 2as[/tex]
=> [tex] 5.80^2 = 3.00^2 + 2 * a * [ [\frac{2}{3} * l ][/tex]
=> [tex] 5.80^2 = 3.00^2 + 2 * a * [ [\frac{2}{3} * 1.5 ][/tex]
=> [tex] 5.80^2 = 3.00^2 + 2 * a * [1 ][/tex]
=> [tex]a = 12.32 \ m/s^2[/tex]
Generally magnitude of the force F during this interval in N is mathematically represented as
[tex]F = m (a + g )[/tex]
=> [tex]F = 46.0 (12.32 + 9.8 )[/tex]
=> [tex]F = 1017.52 \ N[/tex]
In certain cases, using both the momentum principle and energy principle to analyze a system is useful, as they each can reveal different information. You will use the both momentum principle and the energy principle in this problem.A satellite of mass 7500 kg orbits the Earth in a circular orbit of radius of 8.7 106 m (this is above the Earth's atmosphere).The mass of the Earth is 6.0 1024 kg.What is the magnitude of the gravitational force on the satellite due to the earth
Explanation:
The gravitational force equation is the following:

Where:
G = Gravitational constant = 
m1 & m2 = the mass of two related objects
r = distance between the two related objects
The problem gives you everything you need to plug into the formula, except for the gravitational constant. Let me know if you need further clarification.
A bird uses 10 N of force to pull a worm out of the ground a distance of 3 inches. How much work did the bird do?
Answer:
The work done by the bird is 0.762 J
Explanation:
Given;
force applied by the bird, f = 10 N
distance the bird moved the worm, d = 3 inches = 0.0762 m
The work done by the bird is given by;
W = F x d
where;
W is the work done by the bird
d is the distance the bird moved the load
Substitute the given values and estimate the work done by the bird;
W = 10 x 0.0762
W = 0.762 J
Therefore, the work done by the bird is 0.762 J
What is the force with which a body
is attracted by the earth towards its centre?
| वह कौन सा बल है जिसके कारण कोई भी
व्तुपर्थृवी के केंद्र की ओर आक र्तष होती है?
A : Mass | द्रव्यमान
B : Weight | भार
C : Volume | आयतन
D : Density | घनत्व
Ans:
B : Weight | भार
Answer:
Explanation:
Gravity
Gravity is the force by which a planet or other body draws objects toward its center. The force of gravity keeps all of the planets in orbit around the sun.
A passenger plane is travelling down the runway with a speed of 20\,\dfrac{\text{km}}{\text{h}}20 h km 20, start fraction, start text, k, m, end text, divided by, start text, h, end text, end fraction, then speeds up with constant acceleration over 2.4\,\text{km}2.4km2, point, 4, start text, k, m, end text over 59\,\text{s}59s59, start text, s, end text. We want to find the final velocity of the plane at the moment of take-off. Which kinematic formula would be most useful to solve for the target unknown?
Given that,
Initial speed, u = 20 km/s
Acceleration of plane, a = 2.4 km/h²
Time, t = 59 s
We need to find the expression to find the final velocity of an object.Let the final velocity is v.
Using the second equation of kinematics:
[tex]\Delta s=ut+\dfrac{1}{2}at^2[/tex]
a is acceleration, [tex]a=\dfrac{v-u}{t}[/tex]
So,
[tex]\Delta s=ut+\dfrac{1}{2}\times \dfrac{v-u}{t}\times t^2\\\\\Delta s=ut+\dfrac{1}{2}(v-u)t\\\\\Delta s=\dfrac{2ut+vt-ut}{2}\\\\\Delta s=\dfrac{vt+ut}{2}\\\\\Delta s=(\dfrac{v-u}{2})t[/tex]
We can use the above formula to find the final velocity (v) of the plane.
What moves up and down in an antenna or transmitter to produce a radio wave?
Answer:
Radio waves move up and down in the antenna or transmister
Explanation:
who is the father of kinematics ?
explain +)
Answer:
FRANZ REULEAUX
Late 19th century kinematics and the theory of machines as seen through the contributions of the German engineering scientist, Franz Reuleaux (1829-1905), often called the "father of kinematics". Extremely famous in his time and one of the first honorary members of ASME, Reuleaux was largely forgotten in much of modern mechanics literature in English until the recent rediscovery of some of his work. In addition to his contributions to kinematics, we review Reuleaux's ideas about design synthesis, optimization and aesthetics in design, engineering education as well as his early contributions to biomechanics. A unique aspect of this review has been the use of Reuleaux's kinematic models at Cornell University and in the Deutsches Museum as a tool to rediscover lost engineering and kinematic knowledge of 19th century history of machine.
A box sits at the top of an incline that is 50.0 cm tall and that makes an angle of 25° with the ground. The box has a mass of 2.0 kg. It is given an initial speed of 3.0 m/s down the incline. If the coefficient of kinetic friction between the box and the incline is 0.10, how long does it take the box to reach the bottom of the incline?
As the box sits at the top of an incline that is 50.0 cm tall and makes an angle of 25° with the ground, The time it takes to reach the bottom of the incline is mathematically given as
t=0.148s
What is the time it takes the box to reach the bottom of the incline?Generally, the equation for the acceleration is mathematically given as
[tex]a=g(sin\theta-uscos\theta)[/tex]
Therefore
a=(9.8sin-(0.15cos35))
a=4.417
Thereofore
v^2=v0^2+2al
[tex]v^2=V0^2+2ahsin\theta\\\\V^2=(2.0+2(4.417))*60*0.01sin35[/tex]
v=2.6533
In conclusion, The time t is
t=v-v0/a
2.65-20/4.417
t=0.148s
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The period of a simple pendulum (T) is the time it takes for the pendulum to make one complete swing (a round trip). g is the acceleration due to gravity. You can do an experiment of measuring the period (T) as a function of string length (l). You linearize the equation so that you can plot your experimental data and and apply a linear trendline. The equation of the trendline has the form y = a x + b, where a is the slope and b is the y-intercept.
Required:
How do you use the slope to determine "little g" ?
Answer:
Please find the answer in the explanation
Explanation:
Given that an experiment of measuring the period (T) as a function of string length (l) is performed. To linearize the equation so that you can plot your experimental data and and apply a linear trendline,
The graph of length L will be plot against square of period T.
Given that the equation of the trendline has the form y = a x + b, where a is the slope which is equal to the acceleration due to gravity and b is the y-intercept.
When length L is plotted against square of period T, a linear graph will be achieved. The S.I unit of the slope will be m/s^2 which is acceleration g.
What are the functions of stems? (Select all that apply.)
Stems absorb water from the soil.
Stems transport water and minerals.
Stems produce additional plants.
Stems help turn the leaves toward sunlight.
Explanation:
A. Stems absorb water from the soil.
B. Stems transport water and minerals.
Hope this helps you
have a good day.
Answer : Stems produce water and soil
And Stems help turn the leaves towards sunlight.
Explanation:
Because of this picture, (if its not obvious), the 2 ones that i got wrong, are not the answer, and the 2 in the middle are is the answer.
A bullet is fired straight up with a muzzle velocity of 1200 ft/s. How high does the bullet go, neglecting any air resistance?
The height of the bullet as it travels is 72727.27 ft.
What is height?Height is the vertical distance between two points. The unit of height is meter (m).
To calculate the height the bullet will go, we use the formula below
Formula:
v² = u²+2gH.............. Equation 1Where:
v = Final velocity of the bulletu = initial velocity of the bulletg = acceleration due to gravityH = Height the bullet will go.Make H the subject of the equation
H = (v²-u²)/2g................ Equation 2From the question,
Given:
u = 1200 ft/sv = 0 m/s (at maximum height)g = -9.8 m/s² (against gravitational force)Substitute these values into equation 2
H = (0²-1200²)/2×(-9.8)H = -1440000/-19.8H = 72727.27 ft.Hence, The height of the bullet as it travels is 72727.27 ft.
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why should you have a good attitude School. 3 pages
Answer:
positive attitude lets you relax, remember, focus and absorb information as you learn. You're ready to welcome new experiences and recognize many different kinds of learning opportunities. And when you can see opportunities, hope increases.
A ball traveling at 15 m/s hits a bat with a force of 200N. How much force does the bat (moving at 20m/s)
hit the ball with?
O 200
O 15
O 20
O 20
Answer:
200 N
Explanation:
Given that,
A ball traveling at 15 m/s hits a bat with a force of 200 N.
We need to find the force that the bat moving at 20 m/s hit the ball with.
We know that, this probelm is based on Newton's third law of motion. The force that the ball exerting on bat should be equal to the force that the bat exerting in the ball but in opposite direction.
It would mean that the ball hits the ball with a force of 200 N. Hence, the correct option is (a).
Find the resistance at 100°C of a silver wire 1 mm in diameter and 1000 centimetre long ?
Answer:
Ro=19.350 & R¹⁰⁰=26.703
Explanation:
In which position is it most likely that the spring has lost its elastic potential energy?
A.W
B.X
C.Y
D.Z
Answer:
w
Explanation:
its not being streched lol hope dis help
Option A is correct. At position W the spring will lose its elastic potential energy. When spring is extended or shortened, work is done. In the spring, elastic potential energy is stored.
What is the elastic potential energy of spring?When a spring is stretched or compressed, work is done. In the spring, elastic potential energy is stored.
The work done is equal to the elastic potential energy stored, assuming no inelastic deformation has occurred.
The potential energy of the spring is equal to the work done on the spring;
Potential energy = Work done
The mechanical potential energy contained in the structure of a material or physical system as it is forced to elastic deformation by work done on it is referred to as elastic energy.
When things are impermanently crushed, extended, or distorted in any way, elastic energy is released.
The mechanical potential energy stored in the configuration of a material or physical system as it is subjected to elastic deformation by work done on it is referred to as elastic energy.
At position W, the spring has zero deformation. So there should be no stretching causes the potential energy of the system is zero.
Hence option A is correct. At position W the spring will lose its elastic potential energy.
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Select the correct answer.
In the "Describe the situation" step of the decision-making model, which of the following questions may be helpful to ask yourself?
А What decision needs to be made? OB. Why must this decision be made? OC. How will this decision affect me and others?
OD. All of the above
Answer:
d
Explanation:
Determine the equivalent capacitance of the combination shown when C = 12 n
Hi there!
Recall the following.
Capacitors in series:
[tex]C_T = \frac{1}{C_1} + \frac{1}{C_2} +...+ \frac{1}{C_n}[/tex]
Capacitors in parallel:
[tex]C_T = C_1 + C_2 + ... + C_n[/tex]
Begin by solving for the resulting capacitance of both paths.
Path on the left:
[tex]\frac{1}{C_T} = \frac{1}{2C} + \frac{1}{C} = \frac{3}{2C}\\C_T = \frac{2C}{3}[/tex]
Path on the right:
[tex]\frac{1}{C_T} = \frac{1}{C} + \frac{1}{3C} = \frac{4}{3C}\\\\C_T = \frac{3C}{4}[/tex]
Now, since we ADD capacitors in parallel, we can add the resulting capacitances together:
[tex]C_T = \frac{2C}{3} + \frac{3C}{4}[/tex]
Substitute in 12 F for C and solve.
[tex]C_T = \frac{2(12)}{3} + \frac{3(12)}{4} = \frac{24}{3} + \frac{36}{4} = 8 + 9 = \boxed{17F}[/tex]
Select the correct answer.
Good posture is only important when you are exercising.
A.
True
B.
False
what is the distance of sun from earth?
Explanation:
Scientists sometimes call our region of space the "Goldilocks Zone" because it appears to be just right for life. As noted earlier, Earth's average distance to the Sun is about 93 million miles (150 million kilometers) from the Sun.
anaerobic transmission is when you touch a contaminated surface true or false
Anaerobic transmission is when you touch a contaminated surface is a false statement.
What is anaerobic respiration?Anaerobic organisms are the living things that can survive and grow where there is no oxygen in the surrounding environment so we can conclude that Anaerobic transmission is when you touch a contaminated surface is a false statement.
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A certain spring stretches 15 cm when a load of 50.0 N is suspended from it. How much will the spring stretch if 78N is suspended from it
Answer:
23.4 cm
Explanation:
15 : 50 = x : 78
15*78 = 50x
x = 15*78/50 = 23.4 cm
The spring stretch is, 23.4 cm.
What is the stretch of the spring?Potential energy that is stored as a result of the deformation of an elastic item, such as the stretching of a spring, is known as elastic potential energy. It is equivalent to the work required to stretch the spring, which depends on both the length of the stretch and the spring constant, k.What happens to a spring when you stretch it?A spring exerts a force F = -kx in the direction of its equilibrium position when it is stretched or compressed to a length that differs by an amount x from its equilibrium length. A spring's force acts to return the spring to its equilibrium length; it is a restoring force.What causes a spring to stretch?A typical spring is a tightly wrapped metal coil or spiral that stretches when pulled (by applying force) and returns to its original shape when released (remove the force). A spring is elastic, in other words.
According to the question:
15 : 50 = x : 78.
15×78 = 50x.
x = 15×78/50.
= 23.4 cm.
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______________ is the length of the space between two points.
A.
Time
B.
Velocity
C.
Speed
D.
Distance
Answer:
Distance
Explanation:
When using the length of the space between two points, the distance measures the length
Answer:
D.Distance
Explanation:
What are the Economic importance of rusting of iron
Answer:
Rusting is the corrosion of iron which is the most widely used structural metal.
A car accelerates from rest. It reaches a velocity of 25m/s in 10 seconds. What was the cars acceleration?
Answer:
We are Given:
initial velocity (u) = 0m/s
final velocity (v) = 25 m/s
time (t) = 10 seconds
acceleration (a) = a m/s/s
From the first equation of motion, we know that:
v = u + at
solving for a, we get:
a = (v-u) / t
now, plugging the given values in this equation
a = (25 - 0) / 10
a = 25 / 10
a = 2.5 m/s/s
Therefore, the acceleration of the car is 2.5 m/s/s
A projectile in flight explodes into several fragments. The total momentum of the fragments immediately after this explosion: ___________
a. is the same as the momentum of the projectile immediately before the explosion
b. has been changed into kinetic energy of the fragments
c. is less than the momentum of the projectile immediately before the explosion
d. is more than the momentum of the projectile immediately before the explosion
e. has been changed into radiant energy
Answer:
answer is a.
Explanation:
Newton's first law: inertia
If you still can't get it, look at the book.
the conservation of momentum:
the total momentum of a system is conserved, provided that there is no external net force acting on the system.
The total momentum of a system is conserved. Therefore, the total initial momentum of a body after collision is equal to the total final momentum. Thus, option a is correct.
What is momentum ?Momentum of an object is the ability of an object to bring the force applied to make a maximum displacement. It is the product of its mass and velocity. Momentum is a vector quantity. It have both magnitude and direction.
The momentum in a collision is conserved. Thus total initial momentum is equal to the final momentum. Let m be the colliding mass and the u and v be the initial and final velocity.
Then, mu = m v after collision.
The initial momentum of the flight will be equal to the total momentum of the fragments immediately after the explosion. This is called conservation of momentum.
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19. Two objects of equal masses collide head-on while moving in the opposite directions and join together. Show that the fractional loss of original KE of the objects is given by the 1 expression.
E=(1/2)+(V1V2/V1²+V2²)
Answer:
Explanation:
mass of each object = m
momentum conservation: mv₁ + mv₂ = 2mv, so v = (v₁ + v₂)/2
Initial KE = mv₁²/2 + mv₂²/2 = m(v₁² + v₂²)/2
final KE = (2m)v²/2 = m(v₁ + v₂)²/4
Change in KE = m(v₁² + v₂²)/2 - m(v₁ + v₂)²/4 = m(v₁ + v₂)²/4
= m(v₁² + v₂² + 2v₁v₂)/4 = (1/2) m(v₁² + v₂²)/2 + mv₁v₂/2
Fraction loss = change in KE / initial KE = 1/2 + v₁v₂/(v₁² + v₂²)
Help please it’s urgent
Why do water wet glass ?
Answer:
Forces of attraction between a liquid and a solid surface are called adhesive forces. ... Water wets glass and spreads out on it because the adhesive forces between the liquid and the glass are stronger than the cohesive forces within the water.
A heat engine that propels a ship produces 660 Btu/lbm of work while rejecting 300 Btu/lbm of heat. What is its thermal efficiency
This question involves the concepts of thermal efficiency.
The thermal efficiency of the heat engine is "68.75 %".
Thermal EfficiencyThe thermal efficiency of the heat engine can be given by the following formula:
[tex]\eta=\frac{W}{Q}[/tex]
where,
η = thermal efficiency = ?W = Work output = 660 Btu/lbmQ = Heat Input = W + Rejected Heat = 660 Btu/lbm + 300 Btu/lbm Q = 960 Btu/lbmTherefore,
[tex]\eta=\frac{660\ Btu/lbm}{960\ Btu/lbm}[/tex]
η = 0.6875 = 68.75 %
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