Answer:
The rock takes 1.22 seconds to hit the ground
Explanation:
Free Fall Motion
A free-falling object falls under the sole influence of gravity. Any object that is being acted upon only by the force of gravity is said to be in a state of free fall. Free-falling objects do not encounter air resistance.
If an object is dropped from rest in a free-falling motion, it falls with a constant acceleration called the acceleration of gravity, which value is g = 9.8 m/s^2.
The final velocity of a free-falling object after a time t is given by:
vf=g.t
The distance traveled by a dropped object is:
[tex]\displaystyle y=\frac{gt^2}{2}[/tex]
If we know the height h from which the object was dropped, we can find the time it takes fo hit the ground:
[tex]\displaystyle t=\sqrt{\frac{2y}{g}}[/tex]
[tex]\displaystyle t=\sqrt{\frac{2\cdot 6}{9.8}}[/tex]
[tex]t=1.22\ sec.[/tex]
The rock takes 1.22 seconds to hit the ground
The time taken for the rock to hit the ground from the roof top is 1.1 seconds.
Given the data in the question;
Since the rock was initially at rest
Initial velocity; [tex]u = 0[/tex]Height or distance of roof from the ground; [tex]s = 6m[/tex]Time taken for the rock to hit the ground; [tex]t = \ ?[/tex]
To determine the time taken for the rock to hit the ground, we use the second equation of motion:
[tex]s = u + \frac{1}{2}at^2[/tex]
Where s is the height or distance, u is the initial velocity, t is time taken and a is acceleration due to gravity( since the rock will be under gravity, [tex]a = g = 9.8m/s^2[/tex] )
We substitute our values into the equation
[tex]6m = 0 + [ \frac{1}{2}\ *\ 9.8m/s^2\ * t^2 ]\\\\6m = 4.9m/s^2 \ * t^2\\\\t^2 = \frac{6m}{4.9m/s^2}\\\\t = \sqrt{\frac{6m}{4.9m/s^2}} \\\\t = 1.1s[/tex]
Therefore, time taken for the rock to hit the ground from the roof top is 1.1 seconds.
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Which question asks for an opinion?
A. Can people who visit Mars use the resources there to fuel a return
trip to Earth?
B. How much more radiation reaches Mars's surface than reaches
Earth's surface?
C. Is it a good idea to try to establish human colonies on Mars?
D. Is it possible to establish a human colony on Mars?
Answer:
C
Explanation:
It says is it a good idea the person so 1 person can say no and the other one can say yes so it is asks for a opinion
A question that asks for an opinion is as follows:
Is it a good idea to try to establish human colonies on Mars?Thus, the correct option for this question is C.
What is Opinion?An opinion may be defined as a type of viewpoint, judgment, or statement that is not conclusive, rather than facts, which are true statements. It may vary from person to person, topic to topic, and condition to condition.
The opinion of any individual belongs or relates to one particular person rather than to other people. For example, in this given scenario, some reply to the question with a yes answer. In a manner, it is definitely a good idea to try to establish human colonies on Mars. While some categorized themselves on no side.
Therefore, the correct option for this question is C.
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A car moves with a velocity of 20 m/s to east and the other with velocity of 15 m/s to west. If they move from the same point, how far will each of them travel in 2 minutes? Calculate the distance between them after 2 minutes
Answer:
4.2 km
Explanation:
CAR A(velocity =20m/s to East)
In 1s, it covers 20m.
In 120s(2min),it covers20*120m.=2400m=2.4 km
CAR B(velocity =15m/s to west)
In 1s, it covers 15m.
In 120s, it covers 15*120m.=1800m=1.8km
Now, distance between the two cars after 2 minutes =2.4 km+1.8 km=4.2km
there are 2 speed cameras,one in area where the speed limit is 30km/h,and another in area where the speed limit is 50km/h,IN WHICH ONE WILL THERE BE A SMALLER TIME INTERVAL BETWEEN THE PHOTOGRAPHS,explain your answer.
(help)
Answer:
Where speed limit of speed camera is 50 km/h.
Explanation:
Speed cameras work on the principal that photos reflected from the moving car have a higher or lower frequency. This is the Doppler principal. In a car traveling at the speed of light, the waves/particles will not be able to catch up with that car thus no photon will reflect back to the receiver/speed camera thus no speed will be record. Such a speed is impossible to achieve due to the amount of infinite energy expenditure required. This means if the speed is higher and approaching that of light, the frequency of reflected photons will be very high causing high amounts of energy that could damage the speed camera and cause detection. When the car travels at a higher speed, the photos frequency is high thus more energy they will carry and high chances of the vehicle being detected. This means the time interval of photos taken will be smaller.
2. A sphere has a radius of 5.00 cm. with an uncertainty of 5%,
a) what is the percent uncertainty of the volume? _______%
b) What is the volume of sphere with absolute uncertainty? _____ +/ _____cm^3
Answer:
The percent uncertainty of the volume=[tex]\frac{15.70}{523.59} \times 100=2.99\%[/tex]
The volume of sphere with absolute uncertainty=[tex]523.59 \pm 15.7 cm^3[/tex]
Explanation:
Radius of sphere = 5 cm
Radius with uncertainty r'= [tex]5 \pm 0.05[/tex]
Volume of sphere = [tex]\frac{4}{3} \pi r^3=\frac{4}{3} \pi (r')^3[/tex]
[tex]V=\frac{4}{3} \pi (r')^3\\\frac{dV}{dr'}=4\pi (r')^2[/tex]
Where dV is the uncertainty in volume
dr' is the uncertainty in radius
[tex]dV=4\pi (r')^2 dr'\\dV=4 \pi (5)^2(0.05)\\dV=15.70\\V=\frac{4}{3} \pi (r')^3=\frac{4}{3} \pi (5)^3=523.59[/tex]
The percent uncertainty of the volume=[tex]\frac{15.70}{523.59} \times 100=2.99\%[/tex]
The volume of sphere with absolute uncertainty=[tex]523.59 \pm 15.7 cm^3[/tex]
o be useful in science, a hypothesis must be *
A. measurable
B. observable
C. testable
D. correct
Answer:
the answer is c testable
Select the correct answer. What are the units for the spring constant, k?
A. newton meters
B. newton seconds
C. newtons/meter
D. newtons/second
E. newtons/seconds
Answer:
The spring constant,k is measured in newtons per meter
Answer:
C. NEWTON / METRE is the correct answer .Thank your ☺️☺️
Which do you think is more likely: humans visiting an alien planet or aliens from another planet visiting us?
Plz someone help
Answer:
Explanation:
According to me, humans visiting an alien planet is more likely. This is because the allien planets may not have higher levels of technology.
Whereas in today's world, the technology have come to aqquire a very high position. So it likely that humans could visit the alien planets because of the technology evolved by them.
Hope this helps
plz mark as brainliest!!!!!!
A frog falls from its rainforest tree. If we ignore wind resistance, (a) how much time does it take the frog to fall a distance of 12.0 m? (b) how fast is the frog falling at this point?
Answer:
Explanation:
a) Using the equation of motion
S = ut + 1/2gt²
S is the distance of fall
g is the acceleration due to gravity
t is the time taken
Given S = 12.0m, g = 9.81m/s^2, un= 0m/s
12 = 0+1/2(9.81)t²
12 = 4.905t²²²
t² = 12/4.905
t² = 2.446
t = √2.446
t = 1.56secs
b) To determine how fast is the frog falling at this point, we need to calculate the speed of the frog. Using the equaton v = u+gt
v = 0+9.81(1.56)
v = 15.34m/s
Hence the frog is falling at the rate of 15.34m/s
Brian made this table to organize his notes on changes of state.
A 2-column table with 4 rows. The first column titled change of state has entries melting, freezing, deposition, condensation. The second column labeled energy change has entries gain, lose, gain, lose.
Which change of state has the wrong energy change listed?
condensation
deposition
melting
freezing
Answer:
Deposition
Explanation:
I took the quiz
Deposition is accompanied by a loss in energy as the particles become less energetic hence the entry involving deposition is wrong.
What is phase change?The term phase change simply means a change from one state of matter to another. Phase changes are often accompanied by a loss or gain in energy depending on what process occurred.
The phase change deposition is accompanied by a loss in energy as the particles become less energetic hence the entry involving deposition is wrong.
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Two waves have the following waveforms.
Wave A
U
Wave B
Which conclusion can BEST be supported by the illustrations?
lol i’m in your physical science class what was the answer
match the term with its definition
Mrs. O'Brien was at the stop light at Kentucky Ave and High School Road. She was nearly late for school so when the light changed green she drove the remaining 220m in 11 seconds. What is her acceleration?
Answer:
Explanation:
20
Calculate the mass of a lorry that has a momentum of 4600 kg m/s and a velocity of 15m/s. Give your answer to two decimal places
PLZZZ HELP
What is the power (P) of an electric circuit with a current (1) of 2.5 A and a
voltage (V) of 120 V? The formula for power is P= IV.
Answer:
B. 300 W
Explanation:
2.5 * 120 = 300
Watts is the unit of power
difference between acceleration and decceleration short notes
Answer:
Acceleration is considered to describe an increase or positive change of speed or velocity. On the other hand, deceleration is considered to describe a decrease or negative change of speed or velocity.
What is the trademark of the Harlem Globetrotters?
Li and Raj are playing football. They take turns trying to run past each other with the football. Li weighs 125 pound and Raj weighs 175 pounds. Li discovers that if he changes direction quickly when running, he can always dodge out of the way before Raj can tackle him.
Why is Li able to avoid Raj’s tackle? Choose the best description.
Answer:
Li has less mass and therefore less inertia, so he can change his motion more easily than Raj.
Explanation:
Answer:
Li has less mass and therefore less inertia, so he can change his motion more easily than Raj.
Explanation:
A penny is dropped from a building window. If it takes 1.1 s for it
to hit the ground, how high up is the window?
a 150 m
b 2 m
C 16 m
d 6 m
Answer:6m
Explanation:
I guessed the answer and it was right. It was not the tall ones like 16 or 150 because it only took 1.1 second
Given that,
A penny takes 1.1 seconds to hit the ground.
To find,
How high up is the window?
Solution,
When the penny is dropped, its initial velocity is equal to 0 i.e.[tex]u=0[/tex]. The second equation of motion is used to find the relation between position and time. The second equation of motion is :
[tex]s=ut+\dfrac{1}{2}at^2[/tex]
Where
s is the distance
a is acceleration
Here, s = the height of the window from the ground and a = g i.e. acceleration due to gravity
So,
[tex]s=\dfrac{1}{2}gt^2[/tex]
Put all the values,
[tex]s=\dfrac{1}{2}\times 9.8\times (1.1)^2\\\\s=6.05\ m[/tex]
or
[tex]s=6\ m[/tex]
Answer:
The window is [tex]6\ m[/tex] high. The correct option is (d).
Reference:
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Urgent please!!!!!!!!!!!!!!!!!!!!!!
A program can only create one object of each class.
A. True
B. False
what is my real name
Answer:
Probably Trent or something like that
Answer:
Trent or tranthjhikjhjhuiivd
a ball weighs 0.25 kg and is moving at 15 m/s. what is the momentum of the ball?
Answer:
The answer is 3.75 kgm/sExplanation:
The momentum of an object given it's mass and velocity can be found by using the formula
momentum = mass × velocityFrom the question
mass = 0.25 kg
velocity = 15 m/s
We have
momentum = 0.25 × 15
We have the final answer as
3.75 kgm/sHope this helps you
A go-kart accelerates at a rate
of 12.0 m/s2 How long will it
take the go-kart to reach a
speed of 25 m/s?
please hurry
Answer:
if it is at a speed of 12.5 m / s it would take 2 minutes
Explanation:
WHAT IS PIVOT POINT ?
In financial markets, a pivot point is a price level that is used by traders as a possible indicator of market movement. A pivot point is calculated as an average of significant prices from the performance of a market in the prior trading period.
easy 8th grade question plz help
Answer:
1. B
2. A
3. C
Explanation:
An arrow is shot at 27.0° above the horizontal. Its velocity is 54 m/s, and it hits the target.
Explanation:
(a) What is the maximum height the arrow will attain?
Given:
v₀ᵧ = 54 sin 27.0° m/s = 24.5 m/s
vᵧ = 0 m/s
aᵧ = -9.8 m/s²
Find: Δy
vᵧ² = v₀ᵧ² + 2aᵧΔy
(0 m/s)² = (24.5 m/s)² + 2 (-9.8 m/s²) Δy
Δy = 30.7 m
(b) The target is at the height from which the arrow was shot. How far away is it?
Given:
Δy = 0 m
v₀ᵧ = 54 sin 27.0° m/s = 24.5 m/s
aᵧ = -9.8 m/s²
Find: t
Δy = v₀ᵧ t + ½ aᵧt²
0 m = (24.5 m/s) t + ½ (-9.8 m/s²) t²
t = 5.00 s
Given:
v₀ₓ = 54 cos 27.0° m/s = 48.1 m/s
aₓ = 0 m/s²
t = 5.00 s
Find: Δx
Δx = v₀ₓ t + ½ aₓt²
Δx = (48.1 m/s) (5.00 s) + ½ (0 m/s²) (5.00 s)²
Δx = 241 m
A block is hung by two ropes angled at 30º and 60º respectively. What is the ratio of the tension in the second rope to the tension in the first rope?
A car moving at 30 m/s has 900 kj of kinetic energy. What is the car’s mass?
If a car moving at 30 m / s has 900 kJ of kinetic energy, then the mass of the car would have been 2000 kilograms.
What is mechanical energy?Mechanical energy is the combination of all the energy in motion represented by total kinetic energy and the total stored energy in the system which is represented by total potential energy.
As for the given problem, we have to find out the mass of the car if the car moving at 30 m/s has 900 kJ of kinetic energy.
Kinetic energy = 1 / 2 m v²
900000 = 0.5 × m × 30²
m = 1000 / 0.5
= 2000 kilograms
Thus, If a car moving at 30 m / s has 900 kJ of kinetic energy, then the mass of the car would have been 2000 kilograms.
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difference between acceleration and decceleration
acceleration is considered to describe an increase or positive change of speed or velocity But deceleation is considered to describe a decrease or negative change of speed or velocity
what is the relationship between velocity and kinetic energy?
Answer:
when an object has more velocity, it tends to have less potential energy and more kinetic energy.
Explanation:
kinetic energy is the energy of movment and velocity helps to describe movement
Ice has a density of 0.920 g/cm3. An ice cubes mass is 100 g. What is its volume?
Answer:
[tex]\boxed {\tt 108.695652 \ cm^3}[/tex]
Explanation:
Volume can be found by dividing the mass by the density.
[tex]v=\frac{m}{d}[/tex]
The mass is 100 grams and density is 0.920 grams per cubic centimeters.
Therefore,
[tex]m=100 \ g \\d= 0.920 \ g/cm^3[/tex]
Substitute the values into the formula.
[tex]v=\frac{100 \ g}{0.920 \ g/cm^3}[/tex]
Divide. Note that the grams, or "g" will cancel each other out.
[tex]v- 108.695652 \ cm^3[/tex]
The volume of the ice cube is 108.697652 cubic centimeters.