A child on a sled has a combined mass of 97 kg. At the top of a 3.1 meter hill, the sled has a velocity of 8 m/s. Assuming there is no friction, what would the velocity of the child and sled be when they reach the top of a different 1.2 meter hill?

Answers

Answer 1

Answer:

Explanation:

This is an energy conservation problem in that the total energy available to a system s constant trhoughout the whole problem. That is, in equation form:

TE = PE + KE. This is a bit of a problem due to sig figs here, but I will keep with the rules for them all the way up til the end of the problem (I'll tell you when I veer away from the rule and why I did when I get there).

We first need to find the total energy available to the system and then use that value throughout the rest of the problem.

TE = PE + KE where

PE = mgh (mass times gravity times height of the object) and

KE = [tex]\frac{1}{2}mv^2[/tex] (one-half times the mass of the object times the square of the velocity of the object). We solve for PE first, rounding to the correct number of sig figs:

PE = 97(9.8)(3.1) and

PE = 2900 J (2 sig figs here since all the numbers given have 2 sig figs in them). Now for KE

[tex]KE=\frac{1}{2}(97)(8.0)^2[/tex] which, to 2 sig figs (notice I added a .0 to the 8), is

KE = 2200. This means that the total energy available to the sled throughout the whole trip is

TE = 2900 + 2200 so

TE = 5100 J

Now for the second part of the problem, the sled is at a different height so the PE is different, and we are asked to find the velocity at the top of this second hill. The total energy equation then is

5100 = PE + KE. Solving for PE first:

PE = (97)(9.8)(1.2) and, to 2 sig figs:

PE = 82. Now for the KE:

[tex]KE=\frac{1}{2}(97)v^2[/tex]. Plugging all of that into the total energy equation gives us:

[tex]5100=82+\frac{1}{2}(97)v^2[/tex] and isolating the v:

[tex]v=\sqrt{\frac{2(5100-82)}{97} }[/tex] and this is where I veer away from the sig figs. Doing the subtracting first, as we should, means that we would round to the hundreds place. Since the least significant place in the number 82 is the tens place and the least significant place in the 5100 is in the hundreds place, we round to the hundreds place. But I didn't keep to this rule because I'm not sure how adamant your physics teacher is about sig figs. I'll give you the answer that I would expect from my students (the right one) after I give you this one. I just simply subtracted 5100 - 82 and used the answer the calculator gave me which was 5018:

[tex]v=\sqrt{\frac{2(5018)}{97} }[/tex] gives us that the velocity at the top of the 1.2 meter hill is

10.2 m/s.

Doing this the right way, using the rules for sig figs properly:

[tex]v=\sqrt{\frac{2(1500)}{97} }[/tex] gives us, to 2 sig figs,

v = 1.0 × 10¹ m/s


Related Questions

Why the impact of the loaded truck on a body coming it’s the way is very large even if the

truck is moving slowly​

Answers

Answer: due to large momentum

Explanation:

The impact of the loaded truck is very large on a body coming in its way because of the momentum associated with truck. Truck has a huge mass which is responsible for its large momentum.

Momentum is the product of mass and velocity. Even though the velocity of truck is low but it's mass compensates for it to give large momentum. This large momentum can overwhelm any small body at rest or coming in its way.

A table exerts a force on the ground. The ground exerts

A. no force on the table
B. a greater and opposite force on the table
C. an equal and opposite force on the table
D. a lesser an opposite force on the table

Answers

Answer:

hey from what I know the answer is C

Explanation:

When a book is kept on a table , weight (gravitational force) of book acts on table vertically downwards and as a reaction of weight , table also exerts an equal and opposite ( upward) force on book .

Un repartidor de comida rápida entrega una pizza a una casa que se encuentra a 20 km de distancia y se demora 20 minutos en llegar. De vuelta a la pizzería vuelve más relajado y se demora media hora. ¿Cuál fue su velocidad media en el trayecto completo?

Answers

Answer:

La velocidad media en el trayecto completo es 0.8 [tex]\frac{km}{minutos}[/tex].

Explanation:

La velocidad es una magnitud física que expresa la relación entre el espacio recorrido por un objeto y el tiempo empleado para ello.

En otras palabras, la velocidad es una magnitud que relaciona el cambio de posición (o desplazamiento) con el tiempo.

La velocidad media resulta del cociente entre el desplazamiento seguido por un móvil y el  tiempo transcurrido que se emplea  para realizar dicho desplazamiento:

[tex]velocidad=\frac{desplazamiento}{tiempo}[/tex]

En este caso, un repartidor de comida rápida entrega una pizza a una casa que se encuentra a 20 km de distancia y se demora 20 minutos en llegar. De vuelta a la pizzería vuelve más relajado y se demora media hora. Entonces, el desplazamiento total entre la pizzería y la casa será 40 km, considerando que se dirige a la casa y vuelve a la pizzería.

Por otro lado, el tiempo total será el tiempo en que se dirige a la casa y luego vuelve a la pizzería, es decir 20 minutos + 30 minutos= 50 minutos.

Entonces:

[tex]velocidad=\frac{40 km}{50 minutos}[/tex]

Resolviendo:

velocidad= 0.8 [tex]\frac{km}{minutos}[/tex]

La velocidad media en el trayecto completo es 0.8 [tex]\frac{km}{minutos}[/tex].

As you move from left to right across the electromagnetic spectrum in the image, the wavelength becomes?

A.) Longer
B.) Lower
C.) Shorter
D.) Taller

Answers

Answer:

It is A.) Longer

Explanation:

The shortest wavelength is on the (high energy)left side of the diagram with gamma rays. The longest wavelength waves are radio, around 3 meters. so, as you progress, the wavelengths get longer.

can someone please help me answer these questions

Answers

Answer:

the First one i think is D: it increases

The second i think it is B

i think

Explanation:

Match the items on the left with the best corresponding statement on the right. 1 . chromosomes contains tightly packaged DNA molecules 2 . Carl Correns the person who experimented with four o'clocks 3 . incomplete dominance a change in a gene that results from a reproductive mistake 4 . DNA cell division in which the new cells have the same number chromosomes of as the parent cell 5 . mitosis the person who discovered the principles of genetics 6 . Gregor Mendel the special molecule that is able to store and recover information about traits 7 . R.C. Punnett the person who devised a system of squares used to record genetic problems 8 . mutation a condition in which neither gene of a pair is dominant; instead, they show a blended effect 9 . meiosis cell division in which the new cells have one-half of the original number of chromosomes

Answers

Answer:

1 and 4, 2 and 3, 5 and 9, 6 and 8

Explanation:

7 would not have a pair because there is not enough statements

What must happen for salt and water to form a solution?
O A. The salt and the water must combine to form a new substance.
B. The salt and the water must combine chemically.
C. The water must displace the salt.
O D. The salt must dissolve in the water.

Answers

The answer would be D

a Esboza una gráfica desplazamiento-tiempo en la que se representen dos oscilaciones completas de un oscila
armónico simple, con un periodo de 2,0s y una amplitud de 5,0 cm
b Dibuja sobre los mismos ejes la forma de la onda de un oscilador cuya frecuencia es el doble de la anterior y co
misma amplitud
c Dibuja sobre los mismos ejes la forma de la onda de un oscilador con una amplitud de 2,5 cm y la misma
frecuencia del primer oscilador, pero que está desfasado un cuarto de fase respecto a este

Answers

I would say the answer is c

What is the density of a 2.5-cm3 glass
marble that has a mass of 7.5 g?

Answers

Explanation:

Density=mass/volume

Density=7.5/2.5

density=3g/cm^3

The density of a 2.5-cm3 glass marble that has a mass of 7.5 g is 3g/cm^3.

What do you mean by density ?

The density of a material is the measure of how tightly it is packed together. It is expressed as mass per unit volume.

Density Symbol: D or Density Formula: = m/V, where is the density, m is the object's mass, and V is the object's volume.

Density is the amount of "stuff" in a given amount of space. A block of the heavier element lead (Pb), for example, will be denser than a block of the softer, lighter element gold (Au). A Styrofoam block is less dense than a brick. It is expressed in terms of mass per unit volume.

Density = mass / volume

Density = 7.5 / 2.5

density = 3g/cm^3

Thus, The density of a 2.5-cm3 glass marble that has a mass of 7.5 g is 3g/cm^3.

To learn more about the density, follow the link;

https://brainly.com/question/29775886

#SPJ2

Which one of these are considered as mechanical energy?
Chemical energy
Nuclear energy
Thermal energy
Radiant energy
Electrical energy
gravitational potential energy
rotational kinetic energy
translational kinetic energy
elastic potential energy

Answers

Answer:

gravitational potential energy

Explanation: Hope it helps you:)))

have a good day

What are the similarities and differences between hydraulic and pneumatic systems?

Answers

Answer:

Pneumatics use easily compressible gas like air or pure gas. Meanwhile, hydraulics utilize relatively-incompressible liquid media like mineral oil, ethylene glycol, water, synthetic types, or high-temperature fire-resistant fluids to make power transmission possible.

Explanation:

hope this helps

Why is the sky blue in colour?​

Answers

[tex] \huge\mathrm{Answer࿐}[/tex]

Our Atmosphere is full of freely subtended particles, and when light from sun strikes the particles then scattering occurs, in which blue colour is most scattered and hence causing Sky to appear blue .

Hope it helps !!

_____________________________

[tex]\mathrm{ \#TeeNForeveR}[/tex]

Blue light is scattered in the air in all directions. The scattering is caused by electromagnetic radiation by particles of a smaller wavelength.

the diagram below represents the orbits of earth, comet temple-tuttle, and planet x, another planet in out solar system. arrows on each orbit represent the direction of movement. which objects orbit would have and eccentricity close to 1?


Answers

Answer:

the most elliptical orbit is that of COMETA

Explanation:

The eccentricity of a curve in defined as the ratio between lacia to the focus, called c and the value of the axis greater than

         ε = c / a

if we use Pythagoras' theorem

         c = [tex]\sqrt{a^2 - b^2}[/tex]

   substituting

           ε = [tex]\sqrt{1 - (b/a)^2 }[/tex]

if   ε = 0 we have a circumference

In the diagram presented the orbit of the comet is an ellipse a> b

          ε=[tex]\sqrt{1- x} \\ x = (\frac{b}{a} )^2[/tex]

if we expand in series

             ε = 1 - x/2  

             ε=  [tex]1 - \frac{1}{2} \ (\frac{ b}{a} )^2[/tex]

if we neglect the non-linear terms

            ε = 1

Earth's orbit is a small ellipse

             b / a = 149 10⁶ / 151 10⁶

             b / a = 0.98675

             ε = [tex]\sqrt{1- 0.98675^2}[/tex]

               ε = 0.16

a very small ellipse

Planet X, despite not having data, it seems that the sun is in the scepter of the orbit, so b = a

therefore  both the semi-axes of the curve

        e = a / b

Consequently, the most elliptical orbit is that of COMETA.

3. Identify which of the following probably would not have an effect on the climate of a region:

a. the region is next to a mountain range

b. the region is on the equator

c. a thunderstorm just blew through the region

d. the region is next to the Atlantic Ocean

Answers

C.) A thunderstorm
That’s the Answer

Question 33
Why can human ears hear dolphins' vocalizations while under the water but cannot hear them well on land?
A
The waves in the water travel faster and at a higher frequency than they travel on land.
B
The waves in the water travel faster and at a lower frequency than they travel on land.
C
The waves in the water travel slower and at a higher frequency than they travel on land.
D
The waves in the water travel slower and at a lower frequency than they travel on land.

Answers

Answer:

A. The waves in the water travel faster and at a higher frequency than they travel on land.

Explanation:

The main reason why human ears can hear dolphins' vocalizations while under the water but cannot hear them well on land is because water is denser than air and air particles travel faster in denser particles.

Denser particles also ensures that the frequency of the waves move faster which in turn produces a faster and louder result.

what is instanteanous velocity of the bat at t = 5 s

Answers

K=government that it has

what is mechanics inbranches of physics​

Answers

Answer:

Mechanics: A branch of physics in which we study about the object and properties of an object in form of a motion under the action of the force.

heyy! i’ll give brainliest please help

Answers

Tension force transmitted through the chains.

Answer:

Explanation:

tension beacuse the tension is travling to the up to the crane chane

Given the electron configuration for the following neutral atoms A and B below:

Which statement is false?

(a) energy is required to change I to II

(b) I and II represent different elements

(c) I is the electron configuration of sodium

(d) less energy is required
to remove one electron from II than from I

Answers

Pretty sure it’s b !!

diferencias que existen entre la marcha cuando caminamos, corremos sin balón y corremos con balón

Answers

Answer:

La principal diferencia que existe entre la marcha cuando caminamos y cuando corremos, sea con o sin el balón, es la velocidad: al caminar, la velocidad es mucho menor que al correr, y a su vez, correr sin el balón da la posibilidad de correr mucho más rápidamente, debido a que no se requiere una coordinación entre los pasos y el control del balón.

Por otra parte, además de la velocidad, el ritmo cardiaco que se adquiere al caminar es mucho mas bajo que al correr, donde por causa del esfuerzo se aceleran las pulsaciones, aumentando la frecuencia cardiaca y, por lo tanto, la exigencia cardiovascular.

What acts against the direction of motion and gets larger as an object moves faster

Answers

Answer:

Friction

Explanation:

In the event that the power is applied toward the path inverse to the bearing of movement, it goes against the movement of the item and henceforth the speed of the article diminishes.

Then, in the event that the thing continues to move one way, grinding will dominate and go about as the moving variable.

So, the moving factor would be friction.

A trumpet plays its 3rd harmonic at 510 Hz. It then opens a valve, which adds 0.110 m to its length. What is the new 3rd harmonic frequency? (Hint: Find the original length.) (Speed of sound = 343 m/s) (Unit = Hz)​

Answers

Answer:

f = 459.8 Hz

Explanation:

When a trumpet is playing it is an open tube at both ends, therefore there is a belly in each one, the resonance occurs to

           λ = 2L             1st harmonic

           λ = 2L /2        2nd harmonic

           λ = 2L /3       3rd harmonic

 

the speed of the wave is

           v = λ f

           λ = v / f

we substitute in the third harmonic

            [tex]\frac{v}{f} = \frac{2L}{3}[/tex]            (1)

            L = [tex]\frac{3}{2} \ \frac{v}{f}[/tex]

            L = [tex]\frac{3}{2} \ \frac{343}{ 510}[/tex]

            L = 1.009 m

indicates that to  add ΔL = 0.110 m, so the total length is

            L_total = L + ΔL

            L _total = 1.009 + 0.110

            L _total = 1,119 m

we use equation 1

            f =  [tex]\frac{3}{2} \ \frac{v}{L_{total}}[/tex]

            f = [tex]\frac{3}{2} \ \frac{343}{1.119}[/tex]

            f = 459.8 Hz

A 480 Ω resistor is connected in series to a 360 Ω resistor and a 120-V power supply.
a. Draw the circuit.

Answers

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How do astronomers describe the scale of the universe?

Answers

No one can know the size of the universe, it may in fact be infinitely large.

Explanation:

No one knows the size of the universe because we can't see the entire universe. We can only see the part that is close enough to us that there has been time for the light from it to arrive here. What that means is any part of the universe that it will take more than 14.5 billion years for light to travel to us can not bee seen. It is possible that the universe has no size, that is it is infinite.

We can measure what we call the "visible universe" and that is a sphere around us with a radius of about 50 billion light years, the reason it is more than the age of the universe (14.5 billion years) is because the universe is expanding more rapidly than the speed of light.

The way scientists measure the size of the visible universe is with what is called red shift. Similar to the way a car horn's pitch changes as it passes you due to doppler shift, light too has a shift in is frequency or color depending on if it is moving away or toward you. As light moves away from you it shifts for red and the faster it is moving away the more it shifts. We can estimate the distance objects are away by how much they are red shifted. When we look at the most distance objects we can see they are about 50 million light years away.

A classmate is working with a source that
is labelled 18 V. The classmate refers to
the source as a cell. Why might you think
that the term cell is incorrect? How is the
source most likely related to a cell?​

Answers

The term cell is incorrect because, the average voltage of a cell is 3.40 V and as already mentioned in question, the volt of source is 18 V, so cell couldn't be the appropriate word, actually the source is battery.

Now, the source is most likely related to cell because a battery which is the source here, is made up of a "group of cell".

La contaminación acústica de acuerdo a la organización mundial de la salud medido en decibeles corresponde

Answers

Answer: Si es mayor a 65 dB es considerado dañino.

Explanation: Se considera ruido a todo aquel que supera los 75 dB o torturante aquel mayor a 120 dB según la OMS.

An electric field of 6.1x 10^5 N/C is directed along a charge 2.9 x 10^-19 C. What
is the electric force on the charge?

Answers

Answer:

Electric field is a function 1/r^2

Explanation:

what is the definition of gravity in simple terms?

Answers

Answer:

Gravity, also called gravitation, in mechanics, the universal force of attraction acting between all matter. ... On Earth all bodies have a weight, or downward force of gravity, proportional to their mass, which Earth's mass exerts on them. Gravity is measured by the acceleration that it gives to freely falling objects

1 : A force of attraction that tends to draw particles or bodies together.

2 : The attraction of bodies by the force of gravity toward the center of the earth.

3 : Great seriousness.

can someone help please and thank you:)

Answers

Answer:

The answer is C.

Explanation:

PLEASE ASAP ILL GIVE BRAINLIEST.

Answers

The answer is D I’m very sure
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