Answer:
In a pulley, the ideal mechanical advantage is equal to the number of rope segments pulling up on the object. The more rope segments that are helping to do the lifting work, the less force that is needed for the job.
can anyone help me with this last question?
Answer:
v = 39.6 m/s (first answer option)
Explanation:
Use conservation of mechanical energy.
The starting is completely potential energy and the final is all kinetic energy:
[tex]m*g*h=\frac{1}{2}*m*v^2\\g * h=\frac{1}{2} v^2\\9.8*80=\frac{1}{2} v^2\\v^2=1568\\v\approx 39.6\,\,m/s[/tex]
which agrees with the first answer shown.
Two students are playing catch with a 0.20 kg baseball. The first student throws the ball at 25 m/s. How much work is done by the second student in stopping the ball?
Answer:
W = 62.5 J
Explanation:
Given that,
Mass of a baseball, m = 0.2 kg
Initial speed of first student, u = 25 m/s
Finally, the ball stops, v = 0
We need to find the work done by the second student in stopping the ball. We know that, work done is equal to the change in kinetic energy. It can be given by :
[tex]W=\dfrac{1}{2}m(v^2-u^2)\\\\W=-\dfrac{1}{2}mu^2\\\\W=-\dfrac{1}{2}\times 0.2\times(25)^2\\\\W=-62.5\ J[/tex]
So, the required work done is 62.5 J.
What happens to an object's gravitational potential energy as it falls from some height?
Answer:
Decreases
Explanation:
As an object falls from some height, the gravitational potential energy of the object decreases.
Potential energy is the energy due to the position of a body.
The potential energy is mathematically expressed as:
Potential energy = mass x acceleration due to gravity x height
So, potential energy is directly proportional to mass and height.
The higher the mass and height, the more the potential energy.
Which statement best describes how scientists and engineers work together
in the research and development cycle?
O A. Engineers make a new discovery about nature, and then scientists
do experiments to verify it.
O B. Scientists develop new technology, and then engineers use it to
solve design problems.
C. Scientists make a discovery, and then engineers use it to help
them solve problems with their designs.
D. Engineers develop a new technology, and then scientists use it to
solve design problems.
Answer:
C
Explanation:
A bus traveled 2.5 hours in 150 km. What was its average speed?
s=d/t
v=D/t
a=(v-v.)lt
Answer:
Average speed = 60km/hr
Explanation:
Given the following data;
Time = 2.5 hrs
Distance = 150km
To find the average speed;
Average speed = distance/time
Substituting into the equation, we have
Average speed = 150/2.5
Average speed = 60km/hr
5 A truck travelling at 25 m/s puts on its brakes for 4 s. This produces an acceleration of –2 m/s. What is the truck's
velocity after braking?
Answer: The truck's velocity after braking = 17m/s.
Explanation:
Given: Initial velocity(i) = 25 m/s
Time(t) = 4s
Acceleration(a) = -2 m/s ²
We use the following formula to compute final velocity (v):
[tex]v= i+at\\\\\Rightarrow\ v=25+(-2)(4\ \ \ [\text{Substitute all values}]\\\\\Rightarrow\ v=25-8\\\\\Rightarrow\ v=17\ m/s[/tex]
Hence, the truck's velocity after braking = 17m/s.
A sample of an unknown metal has a mass of 0.5 kg. Adding 1985 J of heat to the metal raises its temperature by 10 K. What is the specific heat of the metal
Answer:
Cp = 397 [J/kg*K]
Explanation:
By means of the energy equation for heat transfer in substances and objects, we can calculate the specific heat. In this way, we have the following equation.
[tex]Q=m*C_{p}*DT[/tex]
where:
Dt = temperature change = 10 [K]
m = mass = 0.5 [kg]
Q = heat = 1985 [J]
Cp = specific heat [J/kg*K]
Now replacing:
[tex]1985=0.5*C_{p}*10\\C_{p}=\frac{1985}{0.5*10}\\C_{p}=397[\frac{J}{kg*K} ][/tex]
What is polarization. How can we remove it?
ILL MARK BRAINLEST
Question 13: A food web of the Yellowstone National Park ecosystem is
provided below. If a sudden outbreak of disease severely reduced the
number of wolves in Yellowstone National Park very rapidly, what are two
changes that might happen to the local food web? Fully explain using
claim, evidence, and reasoning.
Answer:
they all will die and so will we
Explanation:
Answer:
3 animals will thrive better
Explanation:
If the number of wolves is reduced, 3 animal species usually eaten by the wolves will have a better chance of survival.
A satellite is in orbit 3.110106 m from the center of Earth. The mass of Earth is 5.98011024 kg Calculate the orbital
period of the satellite.
Answer:
9194.4278 seconds
Explanation:
Orbital period is given by :
T² = (4π²r³) /GM
G = Gravitational constant = 6.67 * 10^-11
M = 5.9801 * 10^24 kg
r = (3.110 * 10^6 m + 6378000 m) =3110000 + 6378000 = 9488000 m
T² = (4π² * 9488000^3) / (6.67* 10^-11 * 5.9801*10^24)
T² = 3.37197 * 10^22 / 398872670000000
T² = 84537504.161415
T = sqrt(84537504.161415)
T = 9194.4278 seconds
Compared to the cells in a healthy body, Elisa’s cells are getting far fewer ____________________ molecules.
Answer:
glucose
Explanation:
Explain how neutrons enable a nuclear chain reaction to take place. (2)
Answer:
Explanation:
In addition to the 'daughter' products, two or three neutrons also explode out of the fission reaction and these can then collide with other uranium nuclei which are unstable so these cause further fission reactions. This is known as a chain reaction .
Hope this helps
1 point
(e) When food is eaten, some of the radiation the food emits is detectable
outside the body. Which type of radiation would not be detectable outside
the body? Tick one box.*
alpha
beta
gamma
Answer:
alpha radiation
Explanation:
e ) Alpha particles can not be detected outside body as it can not penetrate the layer of skin of our body .
So correct answer is "alpha radiation" .
PLEASE HELP ASAP I'LL GIVE BRAINLY!!
Answer: b or c
Explanation: on khan academy
A boy finds an abandoned mine shaft in the woods, and wants to know how deep the hole is. He drops in a stone, and counts 3 seconds before he hears the "plunk" of the stone hitting the bottom of the shaft. Approximately how deep is the shaft? (Assume a gravitational acceleration of 9.8 m/s2 and no significant air resistance.)
Answer: 9.81 times 3s= 29.43m/s
so 29.43 m/s times 3= 88.29m
Explanation:
A car is coasting backwards downhill at a speed of 3.0 m/s when
the driver gets the engine started. After 2.5 sec, the car is
moving
uphill at 4.5 m/s. Assuming that uphill is the positive
direction, what is the car's average acceleration?
If a car is coasting backward downhill at a speed of 3. 0 meters / s when the driver gets the engine started. After 2.5 sec, the car is moving uphill at 4.5 meters / second . Assuming that uphill is the positive direction the average acceleration of the car would be 3.0 meters / second².
What is acceleration?The rate of change of the velocity with respect to time is known as the acceleration of the object. Generally, the unit of acceleration is considered as meter / seconds².
As given in the problem If a car is coasting backward downhill at a speed of 3. 0 meters / s when the driver gets the engine started. After 2.5 sec, the car is moving uphill at 4.5 meters / second .
The average acceleration of the car = + 4.5 - ( - 3 .0) / 2.5
= 3.0 meters / second ²
Thus , the average acceleration of the car would be 3.0 meters / second².
To learn more about acceleration here, refer to the link given below ;
brainly.com/question/2303856
#SPJ5
describe how an electromagnet can be switched on and off.
Answer:The magnetic field around an electromagnet is just the same as the one around a bar magnet. It can, however, be reversed by turning the battery around. Unlike bar magnets, which are permanent magnets, the magnetism of electromagnets can be turned on and off just by closing or opening the switch.
the length of iron rod at 100 C is 300.36 cm and at 159 C is 300.54 cm.Calculate its length at 0 c and coefficient of linear expansion of iron
Answer:
The length at 0 °C is 300.05 cm
Coefficient of linear expansion of iron is 1.02×10¯⁵ C¯¹
Explanation:
From the question given above, the following data were obtained:
Length (L₁) at 100 °C = 300.36 cm
Temperature 1 (θ₁) = 100 °C
Length (L₂) at 159 °C = 300.54 cm
Temperature 2 (θ₂) = 159 °C
Length (L₀) at 0 °C =?
Coefficient of linear expansion (α) =?
L₁ = L₀ (1 + θ₁α)
300.36 = L₀ (1 + 100α) ....(1)
L₂ = L₀ (1 + θ₂α)
300.54 = L₀ (1 + 159α) ..... (2)
Divide equation (2) by (1)
300.54 / 300.36 = L₀ (1 + 159α) / L₀ (1 + 100α)
1.0006 = (1 + 159α) / (1 + 100α)
Cross multiply
1.0006 (1 + 100α) = (1 + 159α)
1.0006 + 100.06α = 1 + 159α
Collect like terms
1.0006 – 1 = 159α – 100.06α
0.0006 = 58.94α
Divide both side by 58.94
α = 0.0006 / 58.94
α = 1.02×10¯⁵ C¯¹
Substitute the value of α into anything of the equation to obtain L₀. Here we shall use equation (2).
300.54 = L₀ (1 + 159α)
α = 1.02×10¯⁵ C¯¹
300.54 = L₀ (1 + 159 ×1.02×10¯⁵)
300.54 = L₀ (1 + 0.0016218)
300.54 = L₀ (1.0016218)
Divide both side by 1.0016
L₀ = 300.54 / 1.0016
L₀ = 300.05 cm
Summary:
The length at 0 °C is 300.05 cm
Coefficient of linear expansion of iron is 1.02×10¯⁵ C¯¹
4 properties of light
Why does the Moon orbit Earth?
a
There is magnetic attraction between the Earth and
the Moon
b
There is gravitational attraction between the Earth
and the Moon
с
There is chemical attraction between the Earth and
the Moon
d
There is mechanical attraction between the Earth
and the Moon
Answer:
B
Explanation:
Gravity, the attractive force between all masses, is what keeps the planets in orbit. Newton’s universal law of gravitation relates the gravitational force to mass and distance
The force of gravity is what gives us our sense of weight. Unlike mass, which is constant, weight can vary depending on the force of gravity (or acceleration) you feel. When Kepler’s laws are reexamined in the light of Newton’s gravitational law, it becomes clear that the masses of both objects are important for the third law, which becomes a3 = (M1+ M2) × P2. Mutual gravitational effects permit us to calculate the masses of astronomical objects, from comets to galaxies.
1 point
A box weighing 12 Newtons is dragged across a
rough floor with a constant velocity of 1.4 meters
per second. The horizontal applied force pulling
the box is 8.5 Newtons. What is the magnitude of
the friction force the floor exerts on the box?
Your answer
PLEASE ANSWER
Answer:
The magnitude of the friction force that the floor exerts on the box is 8.5 newtons.
Explanation:
From Newton's Laws of Motion and given that box is moving at constant velocity, the net acceleration of the box is zero, meaning that magnitude of friction force is equal to the magnitude of the horizontal applied force. Please notice that friction force is the reaction to the horizontal force. The equation of equilibrium for the box is:
[tex]\Sigma F = F - f = 0[/tex] (1)
Where:
[tex]F[/tex] - Horizontal applied force, measured in newtons.
[tex]f[/tex] - Friction force, measured in newtons.
If we know that [tex]F = 8.5\,N[/tex], then the magnitud of the friction force that the floor exerts on the box is:
[tex]f = F[/tex]
[tex]f = 8.5\,N[/tex]
The magnitude of the friction force that the floor exerts on the box is 8.5 newtons.
Which describes a condition of the neritic zone?
few organisms
ample sunlight
changing salinity
frigid temperatures
Answer:
ample sunlight
Explanation:
Neritic zone have ample of sunlight
What is Neritic zone ?The neritic zone is covered with generally well - oxygenated water , receives plenty of sunlight , have relatively stable temperature , has low water pressure and stable salinity levels .
Hence , correct option is option b) ample sunlight
Learn more about Neritic zone :
https://brainly.com/question/17067679?referrer=searchResults
#SPJ2
Explain the principles of work in physics.
difference between dry cell and simple cell
Simple cells have liquid chemicals, making it harder for it to carry. While as dry cells have no liquid chemicals, making it easier to carry.
A force, 10 N drags a mass 10 kg on a horizontal table with an acceleration of 0.2
m/s2. If the acceleration due to gravity is 10 m/s2, the coefficient of friction between
the moving mass and the table is?
Answer:
20&£+)##&843&()-_££-()&_2+0&&-£_!)
How does the initial velocity of a projectile affect its range?
N - Projectiles with larger initial velocity will go farther
0 - Projectiles with larger initial velocities will not go as far
P-Initial velocity has no effect
Plzzz yaar guys help I really need this ( crying emoji )
Answer:
I believe it is the first one
Which of the following is not a benefit of being multicellular?
we can't see multicellular animal with our naked eyes
A person wants to redesign a large room in a house to have less echoing of sound and more sunlight. Which design solution will best match the persons needs?
(A.) Hang curtains over the windows that will transmit sound waves and absorb light waves.
(B.) add pillows to the furniture that will reflect sound waves and refract light waves.
(C.) Place a thick white carpet on the floor that will absorb sound waves and reflect light waves.
(D.) Add a large mirror on the wall that will refract sound waves and reflect light waves.
Answer:
(A.) Hang curtains over the windows that will transmit sound waves and absorb light waves
Would you do more work moving 100 boxes weighing 12N for 1m or moving a 1000N box, 30cm? Support your answer.
Answer:
The second box
Explanation:
Work done is the force applied to move a body through a particular distance.
Work done = Force x distance
For the first box:
Weight = 12N
Distance = 1m
Work done = 12 x 1 = 12J
For the second box;
Weight = 1000N
Distance = 30cm = 0.3m
Work done = 1000 x 0.3 = 300J
The second box has a higher work done.
The planet Mars is located 228 million kilometers (2.28 x 1011 m) away from the sun. If it takes the sun light 760 seconds does light take to reach Mars from the Sun, how fast is the light travelling?
Answer: hey
Explanation: