Answer:
4.44 hr
Explanation:
distance= rate*time
400km/(90 km/hr)=time
time=4.44 hr
give reasons with examples why houses are made up of bricks and cement instead of metal
Answer:
The most important is that the thermal conductivity of the armadillas several orders of magnitude lower than the thermal conductivity of the metal, therefore it is easier to maintain the temperature in winter
Explanation:
Cement and bricks are used in the construction of houses instead of metal, for several reasons
* The most important is that the thermal conductivity of the armadillas several orders of magnitude lower than the thermal conductivity of the metal, therefore it is easier to maintain the temperature in winter
* Metal has more oxidation problems than brick
* The cost of sheet metal is higher than the cost of cement brick.
A target lies flat on the ground 4 m from the side of a building that is 10 m tall, as shown below.
The acceleration of gravity is 10 m/s^2.
Air resistance is negligible.
A student rolls a 4 kg ball off the horizontal
the roof of the building in the direction of the
target.
The horizontal speed v with which the ball
must leave the roof if it is to strike the target
is most nearly
1. v =√3 /4 m/s.
2. v =4√3 /3 m/s.
3. v = 4 m/s.
4. v = 2√2 m/s.
5. v =√2 / 4 m/s.
6. v =√5 / 4 m/s.
7. v = 4√3 m/s.
8. v = 4√5 m/s.
9. v = 6 m/s.
10. v = 4√2 m/s.
Answer:
v = 2√2 m/s
Explanation:
The following data were obtained from the question:
Height (h) = 10 m
Acceleration due to gravity (g) = 10 m/s²
Horizontal distance (s) = 4 m
Horizontal velocity (v) =.?
Next, we shall determine the time taken for the ball to get to the target.
This can be obtained as shown below:
Height (h) = 10 m
Acceleration due to gravity (g) = 10 m/s²
Time (t) =?
h = ½gt²
10 = ½ × 10 × t²
10 = 5 × t²
Divide both side by 5
t² = 10/5
t² = 2
Take the square root of both side.
t = √2 s
Finally, we shall determine the horizontal velocity as shown below:
Horizontal distance (s) = 4 m
Time (t) = √2 s
Horizontal velocity (v) =.?
s = vt
4 = v × √2
Divide both side by √2
v = 4 /√2
Rationalise the denominator
v = (4 /√2) × √2/√2
v = 4 × √2 / √2 × √2
v = 4 × √2 / 2
v = 2√2 m/s
PLEASE HELP! WILL MARK BRAINLIEST!
In this graphical representation of a vector, which direction is designated as positive?
a) horizontal
b) vertical
c) downward
d) upward
Answer:
D
Explanation:
when you try to find out if it is positive, the line goes from left to right, and in this question the line is going upward.
A 1-kilogram object is thrown horizontally and a 2-kilogram object is dropped vertically at
the same instant and from the same point above the ground. Which of the following will
be the same for both objects at any given instant?
Acceleration is the change in the velocity of the object with time. Acceleration is the same for both objects so both objects will reach the ground at the same time.
How do you find out the common value for both objects?Given that both the object dropped at the same time. So the gravitational acceleration of both the objects will be the same which is nearly 10 m/s.
The force at object 1 is given below.
[tex]F_1 = m_1\times g = m_1\times a_1[/tex]
Where m1 is the mass of object 1 and a1 is the acceleration of object 1.
[tex]F _1 = 1\times 10 = 10 \;\rm N[/tex]
The acceleration of object 1 is calculated as below.
[tex]a_1 = \dfrac{F_1}{m_1}[/tex]
[tex]a_1=\dfrac{10}{1} = 10 \;\rm m/s^2[/tex]
The force at object 2 is given below.
[tex]F_2 = m_2\times g = m_2\times a_2[/tex]
Where m2 is the mass of object 2 and a2 is the acceleration of object 2.
[tex]F_2 = 2\times 10 =20 \;\rm N[/tex]
The acceleration of object 2 is calculated as below.
[tex]a_2 = \dfrac{F_2}{m_2}[/tex]
[tex]a_2=\dfrac{20}{2} = 10 \;\rm m/s^2[/tex]
Hence we can conclude that the acceleration of both the objects is the same at every point so they will reach the ground at the same time.
To know more about the acceleration, follow the link given below.
https://brainly.com/question/12134554.
A force of 50 N acts upon a 10 kg block. Calculate the acceleration of the object.
A man starts walking at a steady speed of 1 m/s and 6s later his son sets off from the same point in pursuit of him, starting at rest and accelerating at 2/3 m/s/s. How far do they go before they are together?
Answer:
The father will walk 6 more meters and the son will walk 12 meters
Explanation:
Uniform Speed and Acceleration
This is a problem where two objects have different types of motion. The father walks at a constant speed and later, his son starts a constant acceleration motion in pursuit of him.
Let's start with the father, whose speed is v=1 m/s during t=6 seconds. He travels a distance:
[tex]x=vt=1*6=6\ m[/tex]
Now the son, starting from rest (vo=0) accelerates at a=2/3 m/s^2. His speed will increase and eventually, he will catch up with his father. Let's suppose it happens at a time t1.
The distance traveled by the son is given by:
[tex]\displaystyle xs=v_o.t_1+\frac{a.t_1^2}{2}[/tex]
Since vo=0:
[tex]\displaystyle xs=\frac{a.t_1^2}{2}[/tex]
The father will continue with constant speed and travels a distance of:
[tex]xf=v.t_1[/tex]
For them to catch up, the distance of the son must be 6 m more than the distance of the father, because of the leading distance he has already taken. Thus:
[tex]xs=xf+6[/tex]
Substituting the equations of each man:
[tex]\displaystyle \frac{a.t_1^2}{2}=v.t_1+6[/tex]
We know a=2/3, v=1:
[tex]\displaystyle \frac{2}{3}\cdot\frac{t_1^2}{2}=t_1+6[/tex]
Simplifying:
[tex]\displaystyle \frac{t_1^2}{3}=t_1+6[/tex]
Multiply by 3:
[tex]t_1^2=3t_1+18[/tex]
Rearranging:
[tex]t_1^2-3t_1-18=0[/tex]
Factoring:
[tex](t_1-6)(t_1+3)=0[/tex]
Solving:
[tex]t_1=6 , t_1=-3[/tex]
Since time cannot be negative, the only valid solution is
[tex]t_1=6\ s[/tex]
The distance traveled by the son in 6 seconds is:
[tex]\displaystyle xs=\frac{2/3\cdot 6^2}{2}[/tex]
[tex]xs=12\ m[/tex]
Note the father will travel
[tex]xf=1*6=6\ m[/tex]
This 6 m plus the 6 m he was ahead of the son, make them meet while walking at 6 seconds.
Answer: The father will walk 6 more meters and the son will walk 12 meters
A train travels from Boston to New York. It travels at a speed of 180 km/h for two hours, speeds up to 200 km/h for the next four hours and then slows down to 120 km/h for the next six hours. What is the average speed of the train for this trip?
Answer:
156 2/3 km/hr
Explanation:
Average speed is found by dividing total distance by total time.
180 km/hr in 2 hrs is 360 miles
200 km/hr in 4 hrs is 800 miles
120 km/hr in 6 hrs is 720 miles
Total time is 12 hrs; Total distance 1880 hrs
Divide distance by time and you have 156 2/3 km/hr. This is your average speed.
The gravitational constant G was first measured accurately by Henry Cavendish in 1798. He used an exquisitely sensitive balance to measure the force between two lead spheres whose centers were 0.27 m apart. One of the spheres had a mass of 188 kg, while the mass of the other sphere was 0.93 kg.
What was the ratio of the gravitational force between these spheres to the weight of the lighter sphere?
The gravitational force between the spheres is
[tex]F_{\rm g}=\dfrac{G(188\,\mathrm{kg})(0.93\,\mathrm{kg})}{(0.27\,\mathrm m)^2}\approx1.6\times10^{-7}\,\mathrm N[/tex]
where G = 6.674 x 10⁻¹¹ N m²/kg².
The weight of the lighter sphere is
[tex]F_{\rm w}=(0.93\,\mathrm{kg})g\approx9.1\,\mathrm N[/tex]
where g = 9.80 m/s².
The ratio between the two forces is then
[tex]\dfrac{F_{\rm g}}{F_{\rm w}}\approx1.8\times10^{-8}[/tex]
A metric unit of volume equal to a milliliter
Leah is sitting on of her surfboard out in the ocean. She is waiting for the perfect wave to come along so she can ride it in to
shore. As she waits, she notices that the waves roll by in patterns, or sets.
As Leah its, she counts the number of waves that pass her during a 10-second period; she counts just 1. She estimates that the
distance between crests is 6 meters. Betty sees the perfect wave and begins paddling. She pushes herself up, stands on the
surfboard and rides the wave all the way in to shore, a distance of about 60 meters. It takes her about 10 seconds to ride the
wave in. Use two methods to calculate the speed of the wave based on the information presented. Are they the same? Explain
how you got your answers.
Answer:
No
Explanation:
S=d/t Speed equals distance divided by time. That's a helpful equation in this case. Leah's wave took 10 seconds, and the distance was 6 meters.
6/10=.6
Betty's wave took 10 seconds, but the distance was 60 meters this time.
60/10=6
We know that 6 and .6 are not the same numbers, so we can see that the waves aren't the same.
<3
What happens to the temperature of a substance while it is changing state?
Answer:
its temperature stays constant
Explanation:
Someone is spinning a basketball on his finger. If it is spinning at a rate of 8.92 times per second, what is the basketball's angular velocity in units of radians per second?
Answer:
angular velocity = 56.04 rad/s.
Explanation:
It is given that,
The baseball is spinning at the rate of 8.92 times per second.
We need to find the basketball's angular velocity in units of radians per second.
Here, frequency of the baseball is 8.92 Hz.
We know that Angular velocity is given by :
[tex]\omega=2\pi f\\\\\omega=2\pi \times 8.92 \\\\\omega=56.04\ rad/s[/tex]
So, the angular velocity of the basketball is 56.04 rad/s.
ASAP PLEASE :)
How can we add kinetic energy to a baseball or football?
Answer:
Hitting it or throwing it with force.
State and explain Gauss's law in
electrostatics and use it to determine the electric field
intensity due to a line charge.
To find:-
To find the electric field due to a point charge using Gauss's Law .Answer:-
Gauss's law in electrostatics states that the electric flux through a closed surface is equal to 1/ε0 times the charge enclosed by that surface, that is,
[tex]\implies \displaystyle \phi_E = \oint \vec{E} .\vec{ds} \\[/tex]
Also ,
[tex]\implies\displaystyle \oint \vec{E}.\vec{ds} =\dfrac{q}{\epsilon_0} \\[/tex]
Linear density of charge:-
It ise defined as charge per unit length. Mathematically,
[tex]\implies\displaystyle \lambda =\dfrac{q}{\ell} \\[/tex]
where ,
[tex] q[/tex] is the charge .[tex]\ell[/tex] is the length of the conductor.For figure see attachment.
Now let us assume that the linear density of charge is [tex]\lambda[/tex] . There is a point P near the wire at a distance of " r " from it , where we are interested in calculating the electrical field. Imagine a coaxial Gaussian cylinder of length [tex]\ell[/tex] , and radius " r " such that the point P lines on its surface.
Calculating Electrical flux through the cylinder:-
[tex]\implies\displaystyle \phi_E = 0 + 0 + \oint E.ds \\[/tex]
[tex]\implies\displaystyle\phi_E = \oint E.ds \ \cos0^o \\[/tex]
[tex]\implies\displaystyle \phi_E = \oint Eds \\[/tex]
[tex]\implies\displaystyle \phi_E = E\oint ds \\[/tex]
[tex]\implies\displaystyle \phi_E = E (2\pi r\ell) \ \ dots (1) \\[/tex]
From Gauss's law:-
[tex]\implies\displaystyle \phi_E =\dfrac{q}{\epsilon_0} \\[/tex]
[tex]\implies\displaystyle \phi_E = \dfrac{\lambda \ell}{\epsilon_0}\ \dots (2) \\[/tex]
Therefore , from equation (1) and (2) , we have;
[tex]\implies\displaystyle E \times 2\pi r \ell =\dfrac{\lambda\ell}{\epsilon_0}\\[/tex]
[tex]\implies\displaystyle \underline{\underline{\green{ E =\dfrac{1}{4\pi \epsilon_0}\dfrac{2\lambda}{r}}}}\\[/tex]
And we are done!
A car travels at a constant speed around a circular track whose radius is 3.22 km. The car goes once around the track in 248 s. What is the magnitude of the centripetal acceleration of the car
Answer:
a = 1,838.17m/s²
Explanation:
centripetal acceleration a = v²/r
v is velocity of the car
r is the radius = 3.22km = 3220m
time t = 248
First is to find to velocity using the equation of motion:
v = u+gt
v = 0+(9.81)(248)
v = 2,432.88m/s
a = 2,432.88²/3220
a = 5,918,905.0944/3220
a = 1,838.17m/s²
The magnitude of the centripetal acceleration of the car is 1,838.17m/s²
What are tides?
O Circulation of water
O Glaciers melting causing rising water
O Wind pushing ocean water
O Rise and fall of the water level on the shore
Answer:
4th
Explanation:
Rise and fall of the water level on the sea shore
Work occurs when (2 points) an applied force results in movement of an object in the same direction as the applied force an object is subjected to balanced forces resulting in movement of the object the energy present is the result of the force acting on the object the movement of the object was caused by a force and is in the opposite direction of the force
Answer:
.
Explanation:
A small mailbag is released from a helicopter that is rising\ steadily at 2.32 m/s.
(a) After 5.00 s, what is the speed of the mailbag?
(b) How far is it below the helicopter?
(c) What are your answers to parts (a) and (b) if the helicopter is rising steadily at 2.32 m/s?
Given parameters:
Velocity of the helicopter = 2.32m/s
Time given = 5.00s
Unknown:
a. Speed of the mailbag after 5s
b. How far is the mail bag below the helicopter
Solution:
In this problem, we must apply the appropriate motion equation to solve.
For a;
v = u + gt
v is the velocity of the mail bag
u is the initial velocity
g is the acceleration due to gravity
t is the time taken
Notice that the initial velocity of the mail bag is 0;
V = 0 + 9.8 x 5 = 49m/s
For b;
Using;
h = ut + [tex]\frac{1}{2}[/tex] gt²
where u is 0;
h = [tex]\frac{1}{2}[/tex] x 9.8 x 5² = 122.5m
Being a micro-manager is an example of using effective team building techniques
T or F
Answer:
TRUE
Explanation:
Answer:
True
Explanation:
Where is the magnetic south pole compared to the geographical north pole?
Currently, the magnetic south pole lies about ten degrees distant from the geographic north pole, and sits in the Arctic Ocean north of Alaska. The north end on a compass therefore currently points roughly towards Alaska and not exactly towards geographic north.
A car traveling at 30 m/s is brought to rest at a constant rate in 20 s by applying the brake. a) What is its acceleration? b) How far did it travel after the brake was applied?
leaves uses_,_and_to make food for the plant
light, water, carbon dioxide
Explanation:
c02 , h20 and light
explain which one would have a larger momentum a charging elephant or a buzzing bee
Two point charges of magnitudes +5.00 μC, and +7.00 μC are placed along the x-axis at x = 0 cm and x = 100 cm, respectively. Where must a third charge be placed along the x-axis so that it does not experience any net force because of the other two charges? Two point charges of magnitudes +5.00 μC, and +7.00 μC are placed along the x-axis at x = 0 cm and x = 100 cm, respectively. Where must a third charge be placed along the x-axis so that it does not experience any net force because of the other two charges? 50 cm 45.8 cm 9.12 cm 91.2 cm 4.58 cm
Answer:
45.8 cm
Explanation:
To solve this, we will use the formula
5 / x² = 7/(1 - x)²
5 / x² = 7 / (1 - 2x + x²)
5 / 7 = x² / (1 - 2x + x²)
x = 0.5 * (√(35) - 5) meters
x = 0.5 * (5.916 - 5)
x = 0.5 * (0.916)
x = 0.458 or x = 45.8
The position where the third charge is placed along the x-axis so that it does not experience any net force because of the other two charges is 45.8 cm.
Given :
Two point charges of magnitudes +5.00 μC, and +7.00 μC are placed along the x-axis at x = 0 cm and x = 100 cm, respectively.
The following calculation can be used in order to determine the position where the third charge is placed along the x-axis so that it does not experience any net force because of the other two charges.
[tex]\rm \dfrac{5}{x^2}=\dfrac{7}{(1-x)^2}[/tex]
Simplify the above expression by cross multiplying.
[tex]5(x^2+1-2x)=7x^2[/tex]
[tex]\rm 5x^2 + 5 - 10x = 7x^2[/tex]
[tex]2x^2+2x-1=0[/tex]
Further, simplify the above expression in order to determine the value of x.
x = 0.458
x = 45.8 cm
Therefore, the correct option is b).
For more information, refer to the link given below:
https://brainly.com/question/24391667
Lithium can be found in?
Answer:
Lithium does not occur as the metal in nature. Is found combined in small amounts in nearly all igneous rocks and in the waters of many mineral springs. Spodumene, petalite, lepidolite, and amblygonite are the more important minerals containing lithium.
Lithium can be found in Lithium-ion batteries, some heat-resistant glass and ceramics, some grease lubricants, and some anti-depressant medications.
Which direction is the force of gravity on earth
Answer:
It is toward the center
Explanation:
suppose you put some ice is put into a container of water at room temperature. For faster cooling, the ice should (i) be allowed to float naturally in the water or (ii) be pushed to the bottom of the container with a glass rod and held there. Explain your answer.
Answer:
i am just trying it could be wrong too i am not sure about it but according to me the ans is (1)let ice be allowed to float naturally in the water
Explanation:
if u put water in ice or ice in water the temperature of water decreases and then the process gets slower but if u allow to float it then the temperature of water and surrounding air decreases and the heat is lost from air and water both so here the heat is more than only just water here it allows both to give heat and in 2nd option the heat is only lost by water and gained by icehere it allows only water to give heat so the heat is less in surrounding of ice in water so more heat more faster the process therefore i think the 1st option is correct
A tennis ball is released from a height of 2.0 m above the floor, and then bounces three times. With each bounce, dissipative forces cause it to lose 16.0% of its mechanical energy. How high does it reach after the third bounce?
140 cm
120 cm
120 mm
12 cm
Answer:
12 cm
Explanation:
From what I got with my answer (8.192 cm) I went ahead and rounded it to the closest answer which is 12 cm. Hopefully im correct but if not, I apologize in advance.
this is a Physical Education question
APEX PLEASE HELP
To increase the electricity supply in the country, a government needs to build
a new power plant. Which of the following is a cost associated with the use
of nuclear power that should be factored into its decision?
A. Nuclear power produces radioactive waste.
B. Nuclear power does not depend on wind.
C. Nuclear power does not contribute to climate change.
D. Nuclear power can be produced both day and night.
Answer: A. Nuclear power produces radioactive waste.