A woman skis from rest down a hill 20 m high. If friction is negligible, what is her speed at the bottom of the slope? Select one: O a. 20 m/s O b. 12 m/s O c. 400 m/s O d. 6 m/s​

Answers

Answer 1

Hi there!

We can use the work-energy theorem to solve.

Recall:

[tex]\large\boxed{E_i = E_f}}[/tex]

Initial energy = final energy

The initial energy is purely potential (she starts from rest), and, if we assign the bottom of the slope as the 0 line, her energy at the bottom is purely kinetic.

PE = mgh

KE = 1/2mv²

We can begin by setting the two equal:

mgh = 1/2mv²

Cancel out the mass and rearrange to solve for velocity:

2gh = v²

v = √2gh

Plug in given values and use g ≈ 10 m/s²:

v = √2(10)(20) = 20 m/s


Related Questions


The spring constant of Spring A is twice as great as the spring constant of Spring B. Both springs are stretched the same amount. How does the
force the Spring A applies compare to the force Spring B applies?

Answers

Answer:

FA = 2FB

Force on spring A is twice the Force on spring B

Explanation:

F = kx

FB = (kB)x

FA = (kA)x

FA= (2kB)x

FA = 2(kB)x

FA = 2FB

The force [tex]F_A[/tex] needed to stretch spring A is going to be twice as much as the force [tex]F_B[/tex] needed to stretch spring B.

Explanation:

We know that the spring constants are related as

[tex]k_A = 2k_B[/tex]

The force [tex]F_A[/tex] needed to stretch spring A is given by

[tex]F_A = -k_Ax[/tex]

Also, the force [tex]F_B[/tex] needed to stretch spring is

[tex]F_B = -k_Bx[/tex]

Taking the ratio of the forces, we get

[tex]\dfrac{F_A}{F_B} = \dfrac{-k_Ax}{-k_Bx} = \dfrac{k_A}{k_B}[/tex]

Since [tex]k_A = 2k_B,[/tex] the equation above becomes

[tex]\dfrac{F_A}{F_B} = \dfrac{2k_B}{k_B} = 2[/tex]

or

[tex]F_A = 2F_B[/tex]

This shows that since the spring constant of spring A is twice as large as that of spring B, the force needed is going to be twice as large.

A 2.40 kg ball is attached to an unknown spring and allowed to oscillate. The figure below shows a graph of the ball’s position �� as a function of time . What are the oscillation’s: a. period; b. frequency; c. angular frequency; d. amplitude; and e. What is the force constant of the spring?

Answers

(a) The period of the oscillation is 0.8 s.

(b) The frequency of the oscillation is 1.25 Hz.

(c) The angular frequency of the oscillation is 7.885 rad/s.

(d) The amplitude of the oscillation is 3 cm.

(e) The force constant of the spring is 148.1 N/m.

The given parameters:

Mass of the ball, m = 2.4 kg

From the given graph, we can determine the missing parameters.

The amplitude of the wave is the maximum displacement, A = 3 cm

The period of the oscillation is the time taken to make one complete cycle.

T = 0.8 s

The frequency of the oscillation is calculated as follows;

[tex]f = \frac{1}{T} \\\\f = \frac{1 }{0.8} \\\\f = 1.25 \ Hz[/tex]

The angular frequency of the oscillation is calculated as follows;

[tex]\omega = 2\pi f\\\\\omega = 2\pi \times 1.25\\\\\omega = 7.855 \ rad/s[/tex]

The force constant of the spring is calculated as follows;

[tex]\omega = \sqrt{\frac{k}{m} } \\\\\omega ^2 = \frac{k}{m} \\\\ k = \omega ^2 m\\\\k = (7.855)^2 \times 2.4\\\\k = 148.1 \ N/m[/tex]

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Need quite a bit of help

Answers

When the cart was at Table

Normal reaction (N)=mg

Now acceleration due to gravity acting on the gravity.

When the air comes out of straw it tries to take the cart upwards.But the force is equal to that of acceleration due to gravity but in opposite direction.

Hence.

[tex]\\ \sf\Rrightarrow F_{net}=0N[/tex]

So the cart doesn't move

A textbook weighs 34 N on the surface of the Earth. What is the book’s mass on Earth’s surface?

Answers

Answer:

About 3.47kg

Explanation:

Recall that weight is equal to mass times acceleration.

In this case, our acceleration is due to gravity which on earth is about 9.8m/s/s

So we have 34N=9.8 *mass, divide both sides by 9.8 we get mass is equal to about 3.47kg.

A garden hose shoots water horizontally from the top of a tall building toward the wall of a second building 20 meters away. If the speed with which the water leaves the hose is 5 m/sec, how long does it take the water to reach the second building, and what distance does the water fall in this time?​

Answers

Answer:

Explanation:

If air resistance is ignored, the water travels for a time of

t = d/v = 20 m / 5 m/s = 4 s

falling from vertical rest, the water strikes the wall a distance below the hose

d = ½gt² = ½(10)4² = 80 m

Yeah, I think ignoring air resistance is wishful thinking considering the time and distances involved.

what is the speed of a boy moving around a circular park of radius 6m if he goes around the park in 20s

Answers

Answer:

1.884 meters per second

Explanation:

s = d/t

d = C = 2πr = 2π(6) = 37.68 m

t = 20 s

s = (37.68 m)/(20 s)

s = 1.884 m/s

The speed of the boy is 1.88 m/s while he is moving around a circular park of radius 6m and taking time 20 seconds.

What is speed?

Speed can be defined as a measurement of how quickly the distance an object traveled changes with time. Speed is a scalar quantity as it has magnitude but no direction as a unit of measurement.

An object that moves quickly and with high speed, traveling a lot of ground in a lesser time.

Given, the radius of the circular park, r = 6m,

The time taken to cover one round of the park, t = 20 s

The total distance traveled by the boy is equal to the circumference of the circular park, so

Circumference of park, C = d = 2πr = 2× 3.14 × 6 =37.68 m

The speed of the boy, S = d/t

S = 37.68 /20

S = 1.88 m/s

Therefore, the speed of the boy is equal to 1.88 m/s.

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PLEASE HELPASP WILLGIVE 50 POINT AND BRAINLIEST!!!!!!!!!!!!!!!

A satellite moves in a circular orbit around the Earth at a speed of 5.2 km/s. Determine the satellite’s altitude above the surface of the Earth. Assume the Earth is a homogeneous sphere of radius 6370 km and mass 5.98 × 1024 kg.
The value of the universal gravitational constant is 6.67259 × 10−11 N · m2/kg2

Answers

Answer:

The altitude of the satellite above the surface of the Earth is 1,528.48 km.

F=rmv2=R2GmMrv2=R2GMr=GMv2R2r=(6.67259×10−11)×(5.98×1024)(6900)2×(6,370,000)2r=4,841,516.6 mr=4,841.52 km

A rock sinks straight down the surface of a pond, starting from rest and accelerating at an average rate of 2m/s^2 for the first 3 seconds of its motion. At the 3-second mark, the rock reaches its terminal speed and continues at that speed for the remaining 30 meters of motion. What is the total time it takes for the rock to sink from the surface to the bottom of the lake?

Answers

Answer:

Explanation:

Terminal speed is

2 m/s²(3 s) = 6 m/s

30 m / 6 m/s = 5 s

total sink time is

3 + 5 = 8 s

The total time taken by the rock to sink would be 8 seconds

What is Velocity?

The total displacement covered by any object per unit of time is known as velocity. It depends on the magnitude as well as the direction of the moving object.

The acceleration of the rock for the first three seconds = 2 meters/second²

The time taken to reach the terminal velocity = 3 seconds

terminal velocity = 2 ×3

                           = 6 meters/second²

The time for which the rock sink at terminal velocity = 30 /6

                                                                                       = 5 seconds

total time is taken by the rock to sink = 3 + 5

                                                           =8 seconds

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A train travels at 40m/s. Calculate the time it takes to travel:
A) 30,000 m
B) 50 km

Answers

Answer:

a is 750 second

b is 2 hour

The time it takes for the train to travel 30,000m and 50,000m is 750seconds and 1250 seconds, respectively.

What is speed?

The speed is the distance covered by an object at a particular time. Therefore, it is the ratio of distance and time.

[tex]\rm{Speed = \dfrac{Distance}{Time}[/tex]

A train travels at 40m/s. Now, the time it takes to travel the given distance is,

A.) 30,000m

Speed = Distance / Time

Time = Distance / Speed

Time = 30,000m / 40m/s

Time = 750 seconds

B.) 50 km

1 km = 1000m

50 km = 50 × 1000m = 50,000 m

Speed = Distance / Time

Time = Distance / Speed

Time = 50,000m / 40m/s

Time = 1250 seconds

Hence, the time it takes for the train to travel 30,000m and 50,000m is 750seconds and 1250 seconds, respectively.

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13. In which of the following climates does chemical weathering generally occur most
rapidly?
A. Canda
B. Greenland
C. Brazil
D. Algeria

Answers

Brazil would be the correct answer I believe


Which is the answer

Answers

Answer:

no idea thanks you veryuch

What is the name of Fe(NO3)3

Answers

Answer:

Iron(III) nitrate

Explanation:

What are the two types of force

Answers

Answer:

Forces can be divided into primarily into two types of forces:

Contact Forces. Non-contact Forces.

Explanation:

Where is a divergent boundary most likely to be found?

Answers

Answer:

mid-ocean oceanic ridges

Explanation:

Answer:

mid-ocean oceanic ridges

Explanation:

Divergent boundaries are most likely to be found at mid-oceean oceanic ridges.

The 0.01 kg marble is dropped from rest at A through the smooth glass tube and accumulate in the basket at C as shown in Figure Q2(b). Determine: i) the velocity of the marble at B ii) the horizontal distance R of the basket from the end of the tube, and iii) the speed at which the marble falls into the basket.​

Answers

Crazy Wally Ok Ok ok hhahahaha

The following is an example of what type of reaction?

Answers

Answer:

Single Displacement Reaction

Explanation:

Here, only one element is getting replaced during the reaction, that is, silver gets replaced by copper, hence, single displacement reaction.

Hope it helps :)

According to Hebrews 11, what did Abraham believe God would do if Isaac was slain as a sacrifice?

Answers

Answer:

That he would be happy,for he had ordered him to be sacrificed

identify the origins of breakdown when using a spectrum analyzer

Answers

Four regions of the electromagnetic spectrum that astronomers use when observing objects in the space are the following enumerated answers.

1. First is Ultraviolet

2. Next is Infrared

3. Then the radio

4. Lastly the Visible lights.

These are the answers to the problem.

Một chất điểm khối lượng m=200g chuyển
động chậm dần với vận tốc biến đổi theo qui luật
v=30 – 0,4t2 (SI). Lực hãm tác dụng vào chất điểm
lúc t = 5 giây là
A. 8 N B. 0,8 N C. 4 N D. 0,4 N

Answers

Can you please translate to English?

C. Answer the following questions.
1. Define Earthquake. Write any 3 precautions during earthquake

Answers

Answer:

1. An earthquake is a sudden violent shaking of the ground, typically causing great destruction, as a result of movements within the earth's crust or volcanic action. 2. (3 precautions during an earthquake are)... If you are indoors take cover under a desk, Stay away for glass doors, windows or outside doors and finally drop down or hold on to something until the shaking stops.

Hope that helped?

Explanation:

8.
When minerals seep into and replace the organic cells of a dead organism, creating a
mineral replica of the organism is called ...
Petrification
b. Tar Seeps
C. Amber
d. Mummification

Answers

Answer:

a. petrification

Explanation:

tar seeps = natural trade that, because of its close proximity to the ground surface, seeps from the cracks in the Earth or between rocks forming pits or pools (tar pits)

amber = fossilized resin produced by extinct coniferous trees, typically yellow in color

mummification = a process in which the skin and flesh of a corpse can be preserved by embalming and drying

the conduction of heat from hot body to cold body is an example of what thermodynamics process?

Answers

Answer:

Heat flow

Explanation:

8th grade science !
can someone help me with trying to understand this question for my homework especially how to understand the graph and use that for my evidence and help me give an idea of how should I write the evidence and reasoning?​

Answers

Answer:

for reasoning you could put -> the line is at the top at the left handed sided of the chart (also the beginning) slopes down towards the very bottom right handed side of the chart, symbolising less force as distance goes.

Ben (55kg) is standing on very slippery ice when Junior (25kg) bumps into him. Junior was moving at a speed of 8m/s before the collision. Find the speed of ben and junior as they move across the ice after the collision. Give the answer in m/s. Describe the work you did to get the answer

Answers

Answer:

2.5m/s

Explanation:

m1=55kg

m2=25kg

Ben's velocity before collision=0m/s

Junior's velocity before collision= 8m/s

P1=m1v1+m2v2

P1=55kg(0m/s)+25kg(8m/s)

P1=200kg(m/s)

Know that the momentum before the collision = momentum after the collision

P2=(55kg+25kg)V

200kg(m/s)=(75kg)V

200kg(m/s)/75kg=V

V=2.5m/s.

It makes sense bc after they collide, their speed would slow down, and it wouldn't make sense if the momentum would be greater or less after they collide.

I'm reasking this because I keep getting links not a real answer and I need a proper answer soon please

Answers

Answer:

Adding salt to the water increases the density of the solution because the salt increases the mass without changing the volume very much.

Explanation: the explanation is in a file

i need some help getting started on an essay for physics. i decided on the topic of roller costers and dont know how to start it. see the image on my requirements.​

Answers

Explanation:

force , motion , electric current

Question: Self-test 3.12 Calculate the change in G for ice at -10°C, with density 917 kg mº, when the pressure is increased from 1.0 bar to 2.0 bar.​

Answers

The change in the Gibb's free energy per mole (G) is 1.96 J.

The given parameters:

Density of the ice, ρ = 917 kg/m³Initial pressure, P₁ = 1.0 barFinal pressure, P₂ = 2.0 barTemperature, T = - 10 CMass of water = 18 g

The change in the Gibb's free energy per mole (G) is calculated as follows;

[tex]\Delta G = V(P_2-P_1) \\\\[/tex]

where;

V is the volume of the ice

[tex]Density = \frac{Mass}{Volume} \\\\Volume = \frac{Mass}{Density} \\\\Volume = \frac{18 \times 10^{-3} \ kg}{917 \ m^3} \\\\Volume = 1.96 \times 10^{-5} \ m^3\\\\Volume = 1.96 \times 10^{-5} \ m^3 \times \frac{1000 \ L}{m^3} \\\\Volume = 0.0196 \ L[/tex]

Change in pressure;

[tex]P_2 - P_1 = 2.0 \ bar \ - \ 1.0 \ bar = 1.0 \ bar = 0.987 \ atm[/tex]

The change in the Gibb's free energy per mole (G);

[tex]\Delta G= V(P_2-P_1)\\\\\Delta G = 0.0196\ L \times 0.987\ atm \\\\\Delta G = 0.0193 \ L.atm\\\\1 \ L.atm = 101.325 \ J\\\\\Delta G = 0.0193 \ L.atm \times \frac{101.325 \ J}{1 \ L.atm} \\\\\Delta G = 1.96 \ J[/tex]

Thus, the change in the Gibb's free energy per mole (G) is 1.96 J.

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Zoe is setting up a track for a toy car. The track has a ramp that is 32° above horizontal. If Zoe wants the car to travel as a projectile for 1.0 seconds, how fast does the toy car need to be moving as it leaves the ramp?
4.9 m/s
1.0 m/s
9.2 m/s
7.4 m/s m

Answers

Answer:

Explanation:

Not enough information.

IF we ASSUME she wants the car to be at LAUNCH LEVEL after 1 second of flight.

THEN

The highest point will have zero vertical velocity and will have taken ½ second to get there. This means that the initial vertical velocity was

v = gt

vy₀ = 9.8(0.5)

vy₀ = 4.9 m/s

vsinθ = vy₀

v = vy₀/sinθ

v = 4.9/sin32

v = 9.2466...

v = 9.2 m/s

A swimmer who can swim in still water at a speed of 4km/h is swimming in a river. the river flows at a speed of 3km/h. calculate the speed of the swimmer relative to the river bank when she swims:- 1. downstream 2.upstream​

Answers

Explanation:

Downstream: you just sum the magnitude of the velocity vectors:

3km/h + 4km/h = 7km/h

Upstream: difference of the magnitudes of the velocity vectors, in absolute value:

|3km/h - 4km/h| = 1km/h

Who did the ram caught in the thicket (Genesis 22:13) represent?

Answers

Answer:

I think the answer is goat

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