The velocity of the rock after 2s is 12.56 m/s.
The velocity of the rock at 25 m upwards is 14.68 m/s.
The velocity of the rock at 25 m downwards is -15.97 m/s.
The given parameters;
velocity of the rock, u = 20 m/sheight of the rock, h = 20t - 1.8t²The velocity of the rock after 2s is calculated as follows;
[tex]v = \frac{dh}{dt}= 20 -2(1.86)t \\\\v = 20 - 3.72t\\\\at \ t= 2 \ s \\\\v = 20 - 3.72(2) = 12.56 \ m/s[/tex]
The velocity of the rock when the height is 25 m:
h = 20t - 1.8t²
25 = 20t - 1.8t²
1.8t² - 20t + 25 = 0
solve for the time of motion "t" using quadratic formula
a = 1.8, b = -20, c = 25
[tex]t = \frac{-b \ \ +/- \ \ \sqrt{b^2 - 4ac} }{2a} \\\\t = \frac{-(-20) \ \ +/- \ \ \sqrt{(-20)^2 - 4(1.8\times 25)} }{2(1.8)}\\\\t = 9.67s, \ \ or \ 1.43 \ s[/tex]
The value of t that will give 25 m upwards using the motion model is 1.43 s;
h = 20(1.43) - 1.86(1.43)² = 25 m
The velocity of the rock at 25 m upwards (t = 1.43 s) is calculated as follows;
[tex]v = \frac{dh}{dt} = 20 -3.72t\\\\v = 20 - 3.72(1.43) \\\\v = 14.68 \ m/s[/tex]
The velocity of the rock at 25 m downwards (t = 9.67 s) is calculated as;
[tex]v = \frac{dh}{dt} = 20 - 3.72t\\\\v = 20 - 3.72(9.67)\\\\v = -15.97 \ m/s[/tex]
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Câu 1. Trong dao động điều hoà, phát biểu nào sau đây là không đúng ?
A.Cứ sau một khoảng thời gian T (chu kì) thì vật lại trở về vị trí ban đầu.
B.Cứ sau một khoảng thời gian T thì vận tốc của vật lại trở về giá trị ban đầu.
C.Cứ sau một khoảng thời gian T thì gia tốc của vật lại trở về giá trị ban đầu.
Cứ sau một khoảng thời gian T thì biên độ của vật lại trở về giá trị ban đầu
Answer:
whatttttttttttt
Explanation:
the ಠᴥಠಠᴥಠಠᴥಠಠᴥಠಠᴥಠಠᴥಠಠᴥಠಠᴥಠ
Is my answer correct
Answer:
it right congratulations
Answer:
A
Explanation:
Simply option A is correct
It's a bit of a common sense question
At the highest point it's velocity will be automatically 0 since it is in rest and so is the acceleration
Indicate whether each of the following statements about car collisions is true or false. Select all that are True.
a. If two identical cars with identical speeds collide head on, the magnitude of the impulse received by each car and each driver is the same as if one car at the same speed had collided head on with a concrete wall.
b. Car 1 has mass m, and car 2 has mass 2m. In a head-on collision of these cars while moving at identical speeds in opposite directions, car 1 experiences a bigger acceleration than car 2.
c. The essential safety benefit of crumple zones (parts of the front of a car designed to receive maximum deformation during a head-on collision) is due to their absorbing kinetic energy, converting it into deformation, and lengthening the effective collision time, thus reducing the average force experienced by the driver.
d. Car 1 has mass m, and car 2 has mass 2m. In a head-on collision of these cars while moving at identical speeds in opposite directions, car 1 receives an impulse of bigger magnitude than that received by car 2. If car 1 has mass m and speed v, and car 2 has mass 0.5m and speed 1.5v, then both cars have the same momentum.
Answer:
True statements a, b, and c
Explanation:
Answer d is false because in any collision, each object receives the same impulse. Also the momentum of car 1 is mv, while the momentum of car 2 is 0.5m(1.5v) = 0.75mv
The impulse of collision of cars depends on the mass and velocity of the cars. The statements which are true about the car collisions are option a, b, c.
What is impulse?Impulse is a physical quantity expressed as the product of force and time. The change in momentum mΔV is numerically equals to the impulse F t.
If two identical cars with identical speeds collide head on, the magnitude of the impulse received by each car and each driver is the same as if one car at the same speed had collided head on with a concrete wall. Because they have equal mass and velocity.
The bigger acceleration is experienced by the one which have lighter mass thus car 1 with lower mass experience higher acceleration .
The essential safety benefit of crumple zones (parts of the front of a car designed to receive maximum deformation during a head-on collision) is due to their absorbing kinetic energy.
Converting this energy into deformation, and lengthening the effective collision time, thus reducing the average force experienced by the driver.
The momentum change is proportional to the velocity. The one which have higher velocity is having the higher momentum. Thus car 2 have higher velocity. Thus option d is false.
Therefore, the statements which are true are a, b and c.
To find more about impulse, refer the link below:
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help with this question please.
Answer: Yes Because it matches with the mass and the amount of force Hope this helps :>
Explanation:
describe in the relationships between all four spheres hydrosphere,atmosphere,biosphere and geosphere support your response with examples
Answer:
The spheres interact with one another, and a change in one might result in a change in another. Humans (biosphere) plough the fields with agricultural machinery made of geosphere materials, while the atmosphere (hydrosphere) provides precipitation to water the plants. The biosphere is home to all living organisms on the earth.
Explanation:
don't ask qestionsmm
can anyone heelp me pls pls
Answer:
Lotion : semisolid
Suspension : liquid
capsule : solid
Explanation:
HELP
A 3000-kg truck moving with a velocity of 10 m/s hits a 1000-kg parked car. The impact causes the 1000-kg car to be set in motion at 15 m/s . Assuming that momentum is conserved during the collision, determine the velocity of the truck immediately after the collision.
Answer:
Hey I go to GOC send me your number
Explanation:
A 3 kg drone starts at 5 meter above the ground and reached 25 meter above the
ground. Find the potential energy of the drone. Formula: PE=mghf-hi
Compare and contarst the difference between saturated and unsaturated solutions and supersaturated
Answer:
Unsaturated Solution: Less amount of salt in water, clear solution, no precipitation. Saturated Solution: The maximum amount of salt is dissolved in water, Colour of the solution slightly changes, but no precipitation. Supersaturated Solution: More salt is dissolved in water, Cloudy solution, precipitation is visible
why do the star constellations seem to move across the sky
Answer: These apparent star tracks are in fact not due to the stars moving, but to the rotational motion of the Earth. As the Earth rotates with an axis that is pointed in the direction of the North Star, stars appear to move from east to west in the sky.
Explanation: why do the star constellations seem to move across the sky
Answer:
because the world moves around and around rotating in a circle and circling around the sun so as we move the stars stay the same but to our view it looks like their moving but in reality we are.
Explanation:
Which material(s) listed below is an example of a persistent organic pollutant?
(*select all that apply)
Select 4 correct answer(s)
Ricin
PCBs
DDT
Mercury
Arsenic
Answer:
mercury
arsenic
ricin
ddt
Explanation:
pls mark me as brainliest
Among the materials listed, examples of persistent organic pollutants (POPs) are PCBs (Polychlorinated Biphenyls) DDT (Dichlorodiphenyltrichloroethane). The correct option is (2) and (3).
Persistent Organic Pollutants (POPs) are a class of chemicals that are long-lasting, bioaccumulative, and harmful to humans and wildlife. These pollutants are resistant to degradation and can persist in the environment for long periods of time, resulting in long-distance transport and bioaccumulation in the food chain.
PCBs (Polychlorinated Biphenyls): Once utilized in a variety of industrial applications such as electrical transformers and capacitors, PCBs are now prohibited in many countries due to their toxicity.
DDT (Dichlorodiphenyltrichloroethane): An pesticide that was widely used for agricultural and public health objectives in the past but is now restricted or banned due to its environmental and health effects.
Hence, the correct answer is PCBs and DDT. The correct option is (2) and (3).
To learn more about POPs, here:
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can anyone heelp me pls pls
Answer:
Explanation:
Answer in the pic.. hope it helps
part A
Explain how the students can measure the distance the cars travel.
part B
Explain how the students could measure the time it takes the cars to travel the distance you explained in the first part.
Answer:
Part A: By using the formula, distance = speed x time
Part B: By using the formula, time = distance ( calculated in the first part) ÷ speed
what is the difference between soldering and solder?
Answer:
Soldering is a technique or a process to bond metals with the help of solder. Solder is a metal alloy with a low melting point and is often regarded as the base metal for soldering. The piece or structure that is being bonded together does not get hot enough to melt and this is where solder (base metal) comes into play and creates the connection.
Explanation:
Hope this helps :)
Pls mark brainliest :3
And have an amazing day <3
What provides the centripetal force for the moon's orbit around Earth?
Answer:
Gravitational attraction provides the centripetal force needed to keep planets in orbit around the Sun and all types of satellite in orbit around the Earth. This centripetal force is supplied by gravity. The Earth's gravity keeps the Moon orbiting us. Centripetal force is perpendicular to velocity and causes uniform circular motion. The gravitational attraction of the Sun is an inward force acting on Earth. This force produces the centripetal acceleration of the orbital motion. Centripetal forces are always directed toward the center of the circular path.
Explanation:
Answer: C.
the gravitational pull of the Sun
Explanation: plato :3
Hope this helps!
PLZ HURRY ANSWER THIS PLZ
Which statement best describes how Greensburg recovered from the tornado? O A. It doubled its population O B. It secured itself against future tornadoes. C. It became an eco-tourism destination © D. It built a new school and hospital.
Answer:
C: it became an eco-tourism destination
Explanation:
Answer: Its C
Explanation:
When converted to a household measurement, 9 kilograms is approximately equal to a
Answer:
D) 19.8 lbs
Explanation:
1kg in household measurement is equal to 35.274 ounces. 35.274*9=317.466 ounces.
1kg is also equal to 2.205 lbs. 9*2.205=19.8416
9 kg is also equal to 9000 grams, but grams are not a part of the household measurement system
a) 9000 grams. b) 9000 ounces. c) 19.8 ounces. d) 19.8 pounds.
This leaves us with 19.8 lbs
How can I create a whirlpool of water?
Answer:
To make a small scale whirlpool of water, take a cup and fill it with water and stir. It will create a vortex that pulls particles down.
Or you could see this when draining a tub of water.
True or False
In newton's 2nd law, f=ma there is a correlation between the force and acceleration. This supports that there is a causal relationship that acceleration has on the net force.
Answer: See explanation
Explanation:
Please see attached picture. Due to the fact one of the words in the equation F=ma contains a word not allowed.
How are Classical and positivist theories similar and different?
Answer: PLease see Explanation
Explanation:The key idea behind this theory was to use scientific methods to understand criminality and crime. ... The major difference between the two theories are that classical school is mainly based on free will and suggests that crime as a choice, whereas positivism criminology argues that crime is not a choice.
Please get me 5 star and 1 heart
What landforms are found on the Moon? (Select all that apply.)
mountains
plateaus
lakes
craters
Answer: I think it’s craters
Explanation:
Answer:
MOUNTAINS
CRATERS
PLATEAUS
Explanation:
The Moon has many familiar landforms like mountains, plains, and dark patches that look like seas. We now know that these areas are not seas filled with water. They are deep dry plains.
a block starts from rest and begins sliding down an incline. The block reaches a speed of 12 meters per second as it slides a distance of 50 meters. calculate the blocks rate of acceleration
Vf² = V₁² + 2ad
(12 m/s) ² = (0 m/s) ² + 2 (a) (50m)
a = 1.44 m/s ²
Answer:
[tex]\boxed {\boxed {\sf 1.44 \ m/s^2}}[/tex]
Explanation:
We are asked to find the block's rate of acceleration.
We are given the final velocity, initial velocity, and distance. Therefore, we will use the following kinematic equation:
[tex]{v_f}^2={v_i}^2+2ad[/tex]
The block starts at rest or 0 meters per second. The block reaches a final velocity of 12 meters per second. The distance traveled is 50 meters.
[tex]v_i[/tex]= 0 m/s [tex]v_f[/tex]= 12 m/s [tex]d[/tex]= 50 mSubstitute the values into the formula.
[tex](12 \ m/s)^2 = (0 m/s)^2 + 2a (50 \ m)[/tex]
Solve the exponents.
(12 m/s)² = 12 m/s * 12 m/s = 144 m²/s²(0 m/s)² = 0 m/s * 0 m/s = 0 m²/s²[tex]144 \ m^2/s^2= 0 m^2/s^2 + 2a (50 \ m)[/tex]
The 0 can be subtracted from both sides, or simply canceled.
[tex]144 \ m^2/s^2 = 2a (50 \ m)[/tex]
Multiply 2 and 50 meters.
[tex]144 \ m^2/s^2 = (2 *50 \ m)* a[/tex]
[tex]144 \ m^2/s^2 = (100 \ m)* a[/tex]
We are solving for a, so we must isolate the variable. It is being multiplied by 100 meters. The inverse of multiplication is division, so we divide both sides by 100 meters.
[tex]\frac {144 \ m^2/s^2}{100 \ m}= \frac{(100 \ m)*a}{100 \ m}[/tex]
[tex]\frac {144 \ m^2/s^2}{100 \ m}=a[/tex]
[tex]1.44 \ m/s^2 =a[/tex]
The block's rate of acceleration is 1.44 meters per second squared.
Um cubo fechado com 1 m3 de um líquido (d=0,8; =21 000 kgf/cm2
) é submetido a um aumento de pressão de
20107 N/m2
. Calcule, no Sistema Internacional, as seguintes grandezas:
a) massa final;
b) peso final;
c) volume final;
d) massa volúmica final;
e) peso volúmico final.
Answer:
a. massa final
Explanation:
eu escolhi isso porque essa é a resposta espero que ajude você pode me dar uma ideia?
PLEASE HELP ME!!!!!!!!!!!!!
Answer:
D gravity
Explanation:
please mark me brainliest
Answer:
D. The force that the branch applies to the kitten
Explanation:
I just took the quiz and got it correct!
Two hicers are 13 miles apart and walking toward each other. They meet in 2 hours. Find the rate of each hiker if one hiker walks 1.7 mph faster than the other.
Answer:
Explanation:
Let r be the rate of the slower walker in mph
[r + (r + 1.7)](2) = 13
(2r + 1.7)(2) = 13
4r + 3.4 = 13
4r = 9.6
r = 2.4 mph
r + 1.7 = 4.1 mph
What is the mass of an object that is experiencing a net force of 225 N and an acceleration of 3.0 m/s^2?
Answer:
Mass of a object 75 Kilograms
Explanation:
Net force acting on an object, [tex]Fnet = 225N[/tex]
Acceleration produced, [tex]a = 3.0m/s^2[/tex]
According to Newton's second law :
F = m a
[tex]M =\frac{F}{a}[/tex]
[tex]m =\frac{225N}{300m/s^2}[/tex]
[tex]m= 75 Kg[/tex]
So, the mass of an object is 75kg.
Hence, this is the required solution.
Answer:
75 kg.
Explanation:
Net Force
[tex]\sf \longmapsto F_{net} = 225N[/tex]
Acceleration produced
[tex]\sf \longmapsto \: a = 3 .0 m / {s}^{2}[/tex]
According to Newton's 2nd Law –
F = m•a
[tex]\sf \longmapsto \: M = \frac{F}{A} [/tex]
[tex]\sf \longmapsto \: M = \frac{225N}{300m/s ^{2} } [/tex]
[tex]\sf \longmapsto \: M = \: 75 \: kg[/tex]
Therefore, the mass of an object is 75 kg.
what is the distance between a(-6,3),b(-2,4),c(-8,3)
Answer:
Explanation:
Appears to be the vertexes of a triangle.
AB = √(-6 - (-2))² + (3 - 4)²) = √17
AC = √(-6 - (-8))² + (3 - 3)²) = 2
BC = √(-2 - (-8))² + (4 - 3)²) = √37
A chemical system is considered to have reached dynamic equilibrium when:__________.
a. the frequency of collisions between the reactant molecules is equal to the frequency of collisions between the product molecules.
b. the rate of production of each of the product species is equal to the rate of consumption of each of the reactant species. c. the rate of production of each of the products is equal to the rate of their consumption by the reverse reaction.
d. the sum of the concentrations of each of the reactant species is equal to the sum of the concentrations of each of the product species.
e. the activation energy of the forward reaction is equal to the activation energy of the reverse reaction.
Answer:
D
Explanation:
Sum of the concentrations of each of reactant species is equal to the sum of the concentrations of each of the product species
You are having a snowball fight with your best friend on a frosty winter day. You are standing on the roof of your 5 m tall house with a 0.4 kg snowball. You drop the snowball downward from rest toward your friend,
who is making snow angels below you. Ignoring air resistance, solve for the gravitational potential energy of
the snowball before it is released.
a) 12.5 J
b) 19.6J
c) 5J
d) 2J
Answer: B 19.6J
Explanation: The equation for Potential energy is PE=mgh
PE is the potential energy
m=Mass=0.4kg
g=Gravity=9.81m/[tex]s^{2}[/tex]
h=Height=5 metres
(0.4 kg)*(9.81m/[tex]s^{2}[/tex])*(5 metres)=19.62J
Explain what occurs to satellites when they travel too fast and too slow to keep in orbit
If the satellite goes too slow:
It will crash into it's surrounding things it's orbiting.It would not go forward enough due to pull of gravity.Gravity will pull it back to Earth.The satellite could be knocked or moved closer or farther from the object it is orbiting.If the satellite goes too fast:
It will eventually fly away.It can go forward soo fast.It would go too fastly that gravity can't retain in an orbit.The satellite's inertia would carry it off into space.