Answer:
h = 47 m
Explanation:
First, we will calculate the force on the cord due to the weight:
[tex]Force = F = Weight\\F = mg\\F = (79\ kg)(9.81\ m/s^2)\\F = 775\ N[/tex]
Now, we will calculate the elongation by using Hooke's Law:
[tex]F = k \Delta x[/tex]
where,
k = spring constant = 43 N/m
Δx = elongation = ?
Therefore,
[tex]775\ N = (43\ N/m)\Delta x\\\\\Delta x = \frac{775\ N}{43\ N/m}\\\\\Delta x = 18\ m\\[/tex]
So, the final length of the cord will be:
[tex]Final\ Length = Initial\ Length + \Delta x\\Final\ Length = 35\ m + 18\ m\\Final\ Length = 53\ m\\[/tex]
Hence, the height from water (h) can be found using the following formula:
[tex]h = Height\ of\ Bridge - Final\ Length\ of\ cord\\h = 100\ m - 53\ m\\[/tex]
h = 47 m
2. Bank robbers have pushed a 1000 kg safe to a second story floor-to-ceiling window. They plan to break the window, then lower the safe 3.0 m to their truck. They stack up 500 kg of furniture, tie a rope between the rope and the furniture, and then place the rope over a pulley. Then they push the safe out of the window. What is the safe speed when it hits the truck
Answer:
5.4 m/s
Explanation:
Given that
Mass of the safe, m1 = 1000 kg
Distance to lower the safe, d = 3 m
Mass of furniture, m2 = 500 kg.
Speed of the safe, v = ?
To get the final speed by the time that the safe hits the truck, we first find its acceleration.
The total mass of the system is M = 1000 + 500 kg = 1500 kg
One of the forces acting on the system is that of gravity, and it acts on the safe friction acting on the furniture. Using the formula, we have
= m1*g - mu*m2g
= 1000 * 9.81 - 0.5 * 500 * 9.81
= 7357.5 N
From this calculated weight, we find the acceleration.
Acceleration, a = F/m
Acceleration, a = 7357.5 / 1500
Acceleration, a = 4.905 m/s²
From the question, we know that the Initial speed = 0 m/s
So, employing the use of one of the equations of motion, we have
v² - u² = 2aS
v² - 0 = 2 * 4.905 * 3
v² = 29.43
v = √29.43
v = 5.4 m/s
Explain why Large change in temperature makes heat flow fast and a small change does not.
Answer: Because of the amount of energy
Explanation: Heat is an energy, and small amounts of it does not effect large areas, whereas a very large blast of heat energy can greatly effect the air
an ice skater is moving across a flat and level skating rink and is speeding up. which one of the following statement is true of the ice skater
a) its potential energy is constant
b) its potential energy is increasing
c) its potential energy is decreasing
Answer:
A
Explanation:
The angular momentum of a system of particles around a point in a fixed inertial reference frame is conserved if there is no net external torque around that point:
d
→
L
d
t
=
0
or
→
L
=
→
l
1
+
→
l
2
+
⋯
+
→
l
N
=
constant
.
Note that the total angular momentum
→
L
is conserved. Any of the individual angular momenta can change as long as their sum remains constant. This law is analogous to linear momentum being conserved when the external force on a system is zero.
Based on the image which parachuter will fall fastest
A
B
Or C
Explanation:
c willl fall fast then a and b
0. What is centripetal accleration?Derive relation for it
Answer:
Centripetal acceleration is defined as the property of the motion of an object, traversing a circular path. Any object that is moving in a circle and has an acceleration vector pointed towards the center of that circle is known as Centripetal acceleration. ... Centripetal means towards the center.
Experiments carried out on the television show Mythbusters determined that a magnetic field of 1000 gauss is needed to corrupt the information on a credit card's magnetic strip. (They also busted the myth that a credit card can be demagnetized by an electric eel or an eelskin wallet.) Suppose a long, straight wire carries a current of 5.0 A .
How close can a credit card be held to this wire without damaging its magnetic strip?
Answer:
his distance is too small (r = 0.01 mm), therefore the cut can be at any distance
Explanation:
For this exercise let's use the ampere law.
Let's use a cylinder as the circulating surface
∫ B. ds = μ₀ I
in this case the field is circular and ds is circular therefore the angle between them is zero and cos 0 = 1
B 2π r = μ₀ I
r = [tex]\frac{\mu_o I}{2\pi B}[/tex]
The field needed to demagnetize the card is B = 1000 gauss = 0.1 T
r = [tex]\frac{4\pi 10^{-7} 5.0 }{2\pi \ 0.1}[/tex]
r = 2 10⁻⁷ 5.0/0.1
r = 1 10⁻⁵ m
this distance is too small (r = 0.01 mm), therefore the cut can be at any distance
identify the types of motion in each activity.1.walking a long a hallway. 2.motion of the blades of the fan. 3.earths rotation 4.ball moving on the ground. 5.soldiers marching.
Answer:
1) Linear motion
2) Rotational motion
3) Rotational Motion
4) Random Motion ( The ball can be rolling in any direction)
5) Linear motion
The types of motion in each activity include the following:
Walking a long a hallway- Linear motion Motion of the blades of the fan- Rotational motionEarths rotation- Rotational motion Ball moving on the ground- Random motion Soldiers marching- Linear motion.What is Motion?
This involves an object or a body changing position over time. There are
different types of motion with different examples as can be seen above in
this scenario.
Read more about Motion here https://brainly.com/question/453639
4. While cleaning your bedroom, you move your mattress to vacuum underneath your bed. You use a force of 48 N to move the mattress 1.5 meters out of the way. How much work was done?
Answer:
72 J
Explanation:
Use the Work formula
W= F x d
Given:
F - 48 N
d - 1.5 m
Solution:
W= F x d
W= 48 N x 1.5 m
W= 72 J
A 175-kg roller coaster car starts from rest at the top of an 18.0-m hill and rolls down the hill, then up a second hill that has a height of 8.0 m. When the car reaches the top of the second hill, its speed is 11 m/s. Determine the work done by non-conservative forces on the car as it travels from the top of the first hill to the top of the second hill.
Answer:
The work done by non-conservative forces on the car from the top of the first hill to the top of the second hill is 6574.75 joules.
Explanation:
By Principle of Energy Conservation and Work-Energy Theorem we present the equations that describe the situation of the roller coaster car on each top of the hill. Let consider that bottom has a height of zero meters.
From top of the first hill to the bottom
[tex]m\cdot g \cdot h_{1} = \frac{1}{2}\cdot m\cdot v_{1}^{2} +W_{1, loss}[/tex] (1)
From the bottom to the top of the second hill
[tex]\frac{1}{2}\cdot m\cdot v_{1}^{2} = m\cdot g \cdot h_{2} + \frac{1}{2}\cdot m \cdot v_{2}^{2}+W_{2,loss}[/tex] (2)
Where:
[tex]m[/tex] - Mass of the roller coaster car, in kilograms.
[tex]v_{1}[/tex] - Speed of the roller coaster car at the bottom between the two hills, in meters per second.
[tex]g[/tex] - Gravitational acceleration, in meters per square second.
[tex]h_{1}[/tex] - Height of the first top of the hill with respect to the bottom, in meters.
[tex]W_{1, loss}[/tex] - Work done by non-conservative forces on the car between the top of the first hill and the bottom, in joules.
[tex]v_{2}[/tex] - Speed of the roller coaster car at the top of the second hill, in meters per seconds.
[tex]h_{2}[/tex] - Height of the second top of the hill with respect to the bottom, in meters.
[tex]W_{2, loss}[/tex] - Work done by non-conservative forces on the car bewteen the bottom between the two hills and the top of the second hill, in joules.
By using (1) and (2), we reduce the system of equation into a sole expression:
[tex]m\cdot g\cdot h_{1} = m\cdot g\cdot h_{2} + \frac{1}{2}\cdot m \cdot v_{2}^{2} + W_{loss}[/tex] (3)
Where [tex]W_{loss}[/tex] is the work done by non-conservative forces on the car from the top of the first hill to the top of the second hill, in joules.
If we know that [tex]m = 175\,kg[/tex], [tex]g = 9.807\,\frac{m}{s^{2}}[/tex], [tex]h_{1} = 18\,m[/tex], [tex]h_{2} = 8\,m[/tex] and [tex]v_{2} = 11\,\frac{m}{s}[/tex], then the work done by non-conservative force is:
[tex]W_{loss} = m\cdot\left[ g\cdot \left(h_{1}-h_{2}\right)-\frac{1}{2}\cdot v_{2}^{2} \right][/tex]
[tex]W_{loss} = 6574.75\,J[/tex]
The work done by non-conservative forces on the car from the top of the first hill to the top of the second hill is 6574.75 joules.
An astronomer studies an image taken by a satellite in space and sees an area of gas, dust, and many stars distributed along spiral arms. What is the astronomer most likely seeing?
Answer:the answer is galaxy
Explanation:
1. An electron travels 4.82 meters in 0.00360 seconds. What is its average speed?
Answer:
speed =distance /time
speed =4.82/0.00360
speed =1338.8m/s
The speed of sound in air is around 330 m/s. If a bat emits a single high-pitched ‘click’ of sound in a cave that is 25m wide, calculate the time taken for the echo of the sound to return to the bat.
Answer:
0.15 s
Explanation:
From the question given above, the following data were obtained:
Speed of sound (v) = 330 m/s
Distance (x) = 25 m
Time (t) =?
The time taken for the echo of the sound to the bat can be obtained as follow:
v = 2x / t
330 = 2 × 25 / t
330 = 50 / t
Cross multiply
330 × t = 50
Divide both side by 330
t = 50 / 330
t = 0.15 s
Thus, it will take 0.15 s for the echo of the sound to the bat
Equal amounts of heat are added to equal masses of ice and copper at the same initial temperature. Which substance will have the higher final temperature?
ice
copper
How much greater will that temperature change be than the temperature change of the other substance?
larger ΔT/smaller ΔT
= ?
One of the major effects of heat transfer is temperature change: heating increases the temperature while cooling decreases it. We assume that there is no phase change and that no work is done on or by the system. Experiments show that the transferred heat depends on three factors—the change in temperature, the mass of the system, and the substance and phase of the substance.
Figure a shows a copper-colored cylinder of mass m and temperature change delta T. The heat Q, shown as a wavy rightward horizontal arrow, is transferred to the cylinder from the left. To the right of this image is a similar image, except that the heat transferred Q prime is twice the heat Q. The temperature change of this second cylinder, which is also labeled m, is two delta T. This cylinder is surrounded by small black wavy lines radiating outward. Figure b shows the same two cylinders as in Figure a. The left cylinder is labeled m and delta T and has a wavy heat arrow pointing at it from the left that is labeled Q. The right cylinder is labeled two m and delta T and has a wavy heat arrow pointing to it from the left labeled Q prime equals two Q. Figure c shows the same copper cylinder of mass m and with temperature change delta T, with heat Q being transferred to it. To the right of this cylinder, Q prime equals ten point eight times Q is being transferred to another cylinder filled with water whose mass and change in temperature are the same as that of the copper cylinder.
Why does ice reflect more energy compared to water?
Answer:
while ice is made by water again it melts and becomes water. water is colourless and odourless and has no taste but ice is only cold and hard. water is used for drinking and other things. but is for freshness and it never flows
Explanation:
so ice reflect more energy compared to water
Which is an example of a wedge?
A.
B
C
D
Answer:
B I believe, because the axe is wedged into the log
Answer:
B
Explanation:
I think just rhis is the answer
what is the reaction of zinc nitrate mixed with silver. It's a lab and we are supposed to show what the difference, or any reaction including physical, that would happen.
Answer:
b
Explanation:
Question 2 of 15
When the source of a sound is moving, its speed increases.
A. True
B. False
A capacitor with an initial potential difference of 100 V is discharged through a resistor when a switch between them is closed at t 0.At t 10.0 s, the potential difference across the capacitor is 1.00 V. (a) What is the time constant of the circuit
Answer:
τ = RC = 2.17 s
Explanation:
The voltage through a capacitor can't change instantaneously, so immediately after the switch is closed, the potential difference will keep at 100 V.This voltage will produce a flow of charge (a current) from the capacitor to the resistor, which will be diminishing continuously, till the capacitor be totally discharged, and the current becomes zero.The voltage through the capacitor will follow an exponential function of time, as follows:[tex]V_{C} =V_{o} * e^{-t/RC} (1)[/tex]
Replacing by the givens in (1):[tex]V_{C} = 1.00 V\\V_{o} = 100V\\t = 10.0 s[/tex]
[tex]\frac{1.00V}{100 V} = e^{-10s/RC} (2)[/tex]
Taking ln on both sides in (2), and solving for RC, we have:[tex]R*C= \frac{-10s}{ln 0.01} = 2.17s (3)[/tex]
So, the time constant of the circuit (the product of R times C) is equal to 2.17s.We would like to compare the angular momentum of Mars about its axis of rotation with that of Earth's. The mass of Mars is 11% that of Earth, with a radius 53% that of Earth, and a rotational period 103% that of Earth. Assuming both planets to be uniform spheres calculate the ratio of the angular momentum of Mars to that of Earth.
Explanation:
Assume that mass of Earth is M, radius of earth orbit is R, and rotational period of Earth is T.
The angular momentum of Earth is,
[tex]L_{z} &=M R^{2} \omega \\ &=M R^{2}\left(\frac{2 \pi}{T}\right) \\ &=\frac{2 \pi M R^{2}}{T}[/tex]
The mass of mars is, mass of Earth
=0.11 M
The radius of mars orbit is, of radius of earth
=0.53 R
The rotational period of mars is, of period of Earth
=1.03 T
The angular momentum of mars is,
[tex]L_{m}=\frac{2 \pi(0.11 M)(0.53 R)^{2}}{1.03 T}[/tex]
The angular momentum of mars is,
[tex]L_{m}=\frac{2 \pi(0.11 M)(0.53 R)^{2}}{1.03 T}[/tex]
The ratio of angular momentum of mars to that of earth is,
[tex]\frac{L_{m}}{L_{E}}=\frac{\frac{2 \pi(0.11 M)(0.53 R)^{2}}{1.03 T}}{\frac{2 \pi M R^{2}}{T}} \\ \frac{L_{m}}{L_{E}}=0.03 \\ \frac{L_{m}}{L_{B}}=3.0 \times 10^{-2}[/tex]
Which letter represents the
South American Plate
Answer:
B
Explanation:
Where it shows on the map is B
Pick 3 safety rules in science that you think are important and explain what would happen if the rules were no followed. Used your own word.
Answer:
Answer down below!
Explanation:
Always wear goggles! This is to prevent chemicals or any other substance to get into your eyes. If this wasn't followed, more people could get hurt.Clean up afterwards! Its always better to clean up so someone else couldn't get hurt! If people don't follow this, it could be a mess and someone could get seriously injured.When smelling something, waft it to your face, and not get real close. This is to prevent getting chemicals into your body that could be poisonous. If people didn't folloe this, someone could be seriously sick.A 700 kg horse has 4000 J of kinetic energy as it is running
What is the velocity of the horse?
Answer:
m
Explanation:
Which of the following statements is NOT correct about sea breezes?
A) In a sea breeze, the sand is much warmer than the water, therefore creating a low pressure above the sand.
B) The breeze/wind moves from the sea to the land.
C) The breeze/wind moves from the land to the sea.
D) There is high pressure above the sea, and low pressure above the sand.
The breeze/wind moves from the land to the sea. This statement is NOT correct about sea breezes.
What is sea breeze?Local wind patterns known as sea breezes flow from the sea to land during the day. When there is no strong large-scale wind system and it is very hot or very cold during the day or at night, sea breezes and land breezes alternate along the coasts of large lakes or oceans.
Because the sea breeze's surface flow ends over land, an area of low-level air convergence is created. Locally, this convergence frequently causes air to rise, which promotes the formation of clouds. Showers over land in the afternoon may result from such clouds.
Hence, the sea breeze/wind moves from the land to the sea. This statement is NOT correct about sea breezes.
Learn more about sea breeze here:
https://brainly.com/question/13015619
#SPJ6
Which sentence accurately uses the homophones “they’re,” “there,” or “their”?
Many of the students left there backpacks on the bus.
They’re going to come home as soon as the movie is over.
I think I left the bags of groceries on the floor over their.
These dogs bark at everyone, but there not dangerous at all.
Answer:
They're going to come home as soon as the movie is over.
Answer:
B: They're going to come home as soon as the movie is over.
Explanation:
An ant crawls in a straight line at a constant speed of 0.24 m/s for a distance of 3.0 m, beginning in the corner of a square classroom. It then turns exactly 90 degrees to the right, and proceeds an additional 4.0 m, reaching the far corner of the same wall from which it began. If the second leg of the journey was crawled in half the amount of time as the first, what was the ant's average speed for the whole trip?
Answer:
vavg = 0.37 m/s
Explanation:
The average speed is just the relationship between the total distance traveled, and the total time required for that travel , as follows:[tex]v_{avg} = \frac{\Delta x}{\Delta t} (1)[/tex]
We know that for the first leg of the journey, the ant crawls at a constant speed of 0.24 m/s, moving 3.0 m.We can find the time required for this part, just applying the definition of average velocity, and solving for the time t (which we will call t₁), as follows:[tex]t_{1} =\frac{x_{1}}{v_{1} } = \frac{3.0m}{0.24m/s} = 12.5 s (2)[/tex]
From the givens, we know that the time for the second part is exactly the half of the value found in (2), so we can write the total time Δt as follows:[tex]\Delta t = t_{1} + \frac{t_{1} }{2} = 12.5 s + 6.25 s = 18.75 s (3)[/tex]
We also know that in the second leg of the journey, the ant traveled 4.0 m, which adds to the 3.0 m of the first part, making a total distance of 7.0 m.Per definition of average speed, we can write the following expression as in (1) replacing Δx and Δt by their values, as follows:[tex]v_{avg} = \frac{\Delta x}{\Delta t} = \frac{7.0m}{18.75m} = 0.37 m/s (4)[/tex]
A land breeze forms when:
a) cool air moves down off a mountain towards the coast
b) warm air rises up a mountain slope
c) cool air moves onto a shore from a large body of water
d) warm air from the land moves towards the water
Explanation:
Its D. The warm air from the land moves towards the water
A piano string having a mass per unit length equal to 4.80 ✕ 10−3 kg/m is under a tension of 1,200 N. Find the speed with which a wave travels on this string.
Answer:
500 m/s
Explanation:
From the question,
V = √(T/m')................. Equation 1
Where V = Speed with which the wave travels on the string, T = Tension of the string, m' = Mass per unit length of the string.
Given: T = 1200 N, m' = 4.80×10⁻³ kg/m
Substitute these values into equation 1
V = √(1200/4.80×10⁻³)
V = √(250000)
V = 500 m/s
Hence the speed of the wave in the string is 500 m/s
Conductivity in aqueous solutions, is a measure of the ability of water to conduct an electric current.
a. True
b. False
Answer:
true
Explanation:
i think its true beacuse water can cause electricity
pls let me know if corrct
if yes pls mark brainlest
A satellite, moving in an elliptical orbit, is 368 km above Earth's surface at its farthest point and 164 km above at its closest point. (a) Calculate the semimajor axis of the orbit. Incorrect: Your answer is incorrect. m (b) Calculate the eccentricity of the orbit. Incorrect: Your answer is incorrect. Did you find the semimajor axis a from the greatest and smallest radii
Answer:
a) 6636 km
b) 0.0154
Explanation:
The height above the earth at its furthest point is 368 km
The height above the earth at its closest point is 164 km
Radius of the Earth is 6370 km
The distance of the satellite from the center of the earth to the furthest point is 6370 + 368 km = 6738 km
The distance of the satellite from the center of the earth to the closest point is 6370 + 164 = 6534 km
If we add together the sum of the distance of the satellite from the furthest and its closest distance, it is equal to the 2 major semi axis.
Basically,
2a = R + r
a = (R + r) / 2
a = (6738 + 6534) / 2
a = 13272 / 2
a = 6636 km
Eccentricity, e = (a - r) / a
Eccentricity, e = (6636 - 6534) / 6636
Eccentricity, e = 102 / 6636
Eccentricity, e = 0.0154
Katelyn (55 kg) is practicing a drop jump in the biomechanics lab. She steps off a plyometrics box, lands on the force plate, and immediately jumps back up into the air. Right before she hits the force plate, her vertical velocity is 3.0 m/s downwards. After leaving the ground again, her vertical velocity is 3.5 m/s upwards. Katelyn was in contact with the ground for 0.4 seconds. (a) What was the impulse exerted on Katelyn when she was on the force plate
Answer:
J = 357.5 kg*m/s
Explanation:
The impulse exerted on Katelyn when she was on the force plate, is equal to the change in her momentum, according to Newton's 2nd Law.Assuming as the positive direction the upward direction (coincident with the positive y-axis) we can express the initial momentum as follows:[tex]p_{o} = m*v_{o} = 55 kg * (-3.0 m/s) (1)[/tex]
By the same token, the final momentum is as follows:[tex]p_{f} = m*v_{f} = 55 kg * (3.5 m/s) (2)[/tex]
As we have already said, the impulse J is just equal to the change in momentum, i.e., the difference between (2) and (1):[tex]J = p_{f} - p_{o} = m* (v_{f} -v_{o}) = 55 kg* (3.5m/s- (-3.0m/s)) = 357.5 kg*m/s (3)[/tex]