Answer:
The specific heat of air is 100 J/kg°C.
Explanation:
mass, m = 5 kg
Temperature change, T' - T = 37 °C - 22 °C = 15°C
heat, H = 7500 J
let the specific heat of air is c.
The formula of heat is
H = m c (T' - T)
7500 = 5 x c x 15
c = 100 J/kg°C
A sample of Radon-222 has a half-life of 3.82 days. After 11.46 days, there is 5 grams of Radon-222 remaining. How much Radon-222 was in the original sample?
30 grams
2 grams
15 grams
40 grams
A bullet of mass of 50g is moving with the velocity of 200km/h .calculate the kinetic energy of the bullet .
Answer:
is 10³
Explanation:
cuz the formula of KE is 1/2mv²
covert 50g to kg first then plug in the formula
1/2 × 0.05 × 200 = 10³ J
; (b) A uniform beam 150cm long weighs 3.5kg and
supported on knife-edges at its ends. The beam
supports a weight 7kg at a distance 30cm from
one end. Find the reactions of the supports.
Explanation:
(b) A uniform beam 150cm long weighs 3.5kg and
supported on knife-edges at its ends. The beam
supports a weight 7kg at a distance 30cm from
one end. Find the reactions of the supports.
why a magnetic compass is used to determine the direction.
Answer:
the magnetic compass is used to determine direction because it is one of the most accurate form of magnet as we already know that a freely suspended magnet always faces towards north direction and south direction
What type of sound do the thinner
strings on a guitar make?
A. Higher pitched sounds
B. Lower pitched sounds
C. Loud sounds
D. Quiet sounds
Answer:
d
Explanation:
I'm not perfectly sure so check again
what's is acceleration. ?????
Answer:
Acceleration, rate at which velocity changes with time, in terms of both speed and direction. A point or an object moving in a straight line is accelerated if it speeds up or slows down. ... Acceleration is defined as the change in the velocity vector in a time interval, divided by the time interval.
Answer:
The rate of change in velocity with time A=finall velocity _intial velocity upon time
A person climbs out of swimming pool and stands in the open air.Explain why evaporation of water from the surface of the persons body causes the person to feel cold
Answer:
The person feels cool at first because the swimming pool water is usually cool and he/she has that water on his body. But when it evaporates, the cool air directly touches his body and that's why he/she feels cold.
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An engineer wants to design an oval racetrack such that 3.20×103 lb racecars can round the exactly 1000 ft radius turns at 99 mi/h without the aid of friction. She estimates that the cars will round the turns at a maximum of 175 mi/h. Find the banking angle θ necessary for the race cars to navigate the turns at 99 mi/h without the aid of friction.
Answer:
the angle of banking is 33.3 degree.
Explanation:
speed, v = 99 mi/h = 44.26 m/s
radius, r = 1000 ft = 304.8 m
g = 9.8 m/s^2
Let the angle of banking is A.
[tex]tan A = \frac{v ^2}{r g}\\\\tan A = \frac{44.26^2}{304.8\times 9.8}\\\\tan A = 0.66\\\\A = 33.3^0[/tex]
Define electric current and drift velocity.
Answer:
Current- the flow of free charges, such as electrons and ions
Drift velocity- the average speed at which these charges move
Answer:
An electric current is the stream of changed particals, such as electrons & ions, moving through an electrical conductor.
The average velocity attained bycharged partical ,such as electrons,in a material due to electric fields
HELP ME PLEASE PLEASE
Answer:
b
Explanation
vector is in x direction
Answer:
B. b
its the only vector that reaches up to 3 of the X axis.
Which is an example of current electricity?
Answer:
D
Explanation:
i just did it trust me
A 750 kg National Geographic Drone is rising vertically up into the atmosphere at constant speed. The lift force pushing it upward is 125% of its weight. The drone reaches the cruising speed almost immediately. It takes 25 seconds for the drone to reach a height of 250m starting from the surface.
a. What is the mechanical energy of the drone at the surface?
b. What is the mechanical energy of the drone at the 150 m height?
c. Is the mechanical energy of the drone conserved, increased, or decreased. Explain your choice.
d. What is the work done by each force acting on the drone?
Answer:
a. 0
b. 1.103625 MJ
c. Conserved
d. 1.103625/n MJ where n = The number of forces
Explanation:
The mass of the drone, m = 750 kg
The upward lift force = 125% of the weight of the drone
The time it takes the drone to reach a height of 250 m = 25 seconds
a. The mechanical energy = The kinetic energy + Potential energy
Therefore, given that the drone stars motion from the surface and was initially at rest, the mechanical energy at the surface = 0
b. The mechanical energy at height, h = 150 m, ME₁₅₀ = The potential energy gained = m·g·h
Where;
g = The acceleration due to gravity = 9.81 m/s²
∴ ME₁₅₀ = 750 kg × 9.81 m/s² × 150 m = 1103625 J = 1.103625 MJ
c. The mechanical energy is equivalent to the potential energy of the drone at the 150 m height, therefore, it is conserved
d. The work done by the force = The energy gained
Therefore, where there are n number of forces, the work done by each force = 1.103625/n MJ
Which direction do electrons travel
A.from negative to positive
B.in either direction depending on the circuit
C.from positive to negative
D.they don’t move they simply exchange charge
Answer:
option a negative to positive
Explanation:
The flow of electrons is termed electron current. Electrons flow from the negative terminal to the positive. Conventional current or simply current, behaves as if positive charge carriers cause current flow. Conventional current flows from the positive terminal to the negative
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A particular electric car is supplied with 300 kJ of chemical energy by the battery. Of this, a total of 70.5 kJ of energy is wasted as heat.
Calculate the overall efficiency of the electric car.
[tex]\\ \sf\longmapsto 300-70.5=229.5kJ[/tex]
We know
[tex]\boxed{\sf Efficiency=\dfrac{Used\:Energy}{Supplied\:Energy}\times 100}[/tex]
[tex]\\ \sf\longmapsto Efficiency=\dfrac{229.5}{300}\times 100[/tex]
[tex]\\ \sf\longmapsto Efficiency=\dfrac{229.5}{3}[/tex]
[tex]\\ \sf\longmapsto Efficiency=76.5\%[/tex]
Which two statements are true about a system?
a)A system is a group of objects analyzed as one unit.
b)Energy that moves across system boundaries is conserved.
c)There’s only one way to define the boundaries of a system.
d)All systems are made by humans.
A particle makes 800 revolution in 4 minutes of a circle of 5cm. Find
i. it's period
ii. Angular Velocity
iii. Linear Velocity
iv. It's acceleration
PLEASE FORMULAE SHOULD BE WRITTEN CLEARLY.
YOU CAN SNAP AND SEND
Answer:
i) The period of the particle is 0.3 seconds
ii) The angular velocity is approximately 20.94 rad/s
iii) The linear velocity is approximately 1.047 m/s
iv) The centripetal acceleration is approximately 6.98 m/s²
Explanation:
The given parameters are;
The number of revolution of the particle, n = 800 revolution
The time it takes the particle to make 800 revolutions = 4 minutes
The dimension of the circle = 5 cm = 0.05 m
Given that the dimension of the circle is the radius of the circle, we have;
i) The period of the particle, T = The time to complete one revolution
T = 1/(The number of revolutions per second)
∴ T = 1/(800 rev/(4 min × 60 s/min)) = 3/10 s
The period, T = 3/10 seconds = 0.3 seconds
ii) The angular velocity, ω = Angle covered/(Time)
800 revolutions in 4 minutes = Angle of (800 × 2·π) in 4 minutes
∴ ω = (800 × 2·π)/(4 × 60) = 20·π/3
The angular velocity, ω = 20·π/3 rad/s ≈ 20.94 rad/s
iii) The linear velocity, v = r × ω
∴ The linear velocity, v = 0.05 m × 20·π/3 rad/s = π/3 m/s ≈ 1.047 m/s
iv) The centripetal acceleration, [tex]a_c[/tex] = v²/r
∴ The centripetal acceleration, [tex]a_c[/tex] = (π/3)²/(0.05) = 20·π/9
The centripetal acceleration, [tex]a_c[/tex] = 20·π/9 m/s² ≈ 6.98 m/s²
The energy required to change the state of a substance was determined to be E(H).
If the mass of the substance was DOUBLED, the value of E(H) will
(A) be halved
(B) be doubled
(C) be quadrupled
(D) remain constant
Answer:
ccccccccc or bbbbbbb or aaaaaaaa or ddddddd
During what intervals was Jenny positively accelerating?
Answer:
3:00 - 3:02 and 3:07 - 3:08
Explanation:
Those are the only intervals in which Jenny's speed increased.
Answer and Explanation:
To know where Jenny was positively accelerating, we have to find where the slopes on the graph are increasing (in the positive direction).
By looking at the graph, we can see that at the intervals:
3:00 to 3:02 and 3:07 to 3:08
Jenny was positively accelerating, as there is an increase in speed during these time intervals.
#teamtrees #PAW (Plant And Water)
I hope this helps!
When should a line graph be used?
A. When the independent variable is continuous and shows a causal link to the dependent variable.
B. When the independent variable is composed of categories and does not show a relationship.
C. When there is no independent variable.
D. When the independent variable is continuous and does not show a relationship to the dependent variable.
Answer:
A. When the independent variable is continuous and shows a causal link to the dependent variable.
Explanation:
A graph can be defined as the graphical representation of data (informations) on horizontal and vertical lines i.e x-axis and y-axis respectively.
In an experiment , the variable being manipulated by an experimenter is known as an independent variable while the dependent variable is the event expected to change when the independent variable is manipulated
Generally, a line graph should be used when the independent variable is continuous and shows a causal link to the dependent variable.
This ultimately implies that, a line graph should be used when the data changes continuously over time and as such there exist a linear relationship between the data (variables).
Which word describes the maximum a point moves from its rest position when a wave passes?
Answer:
Amplitude.
Explanation:
A wave can be defined as a disturbance in a medium that progressively transports energy from a source location to another location without the transportation of matter.
In Science, there are two (2) types of wave and these include;
I. Electromagnetic waves: it doesn't require a medium for its propagation and as such can travel through an empty space or vacuum. An example of an electromagnetic wave is light.
II. Mechanical waves: it requires a medium for its propagation and as such can't travel through an empty space or vacuum. An example of a mechanical wave is sound.
An amplitude can be defined as a waveform that's measured from the center line (its origin or equilibrium position) to the bottom of a trough or top of a crest.
Hence, an amplitude is a word that describes the maximum displacement a point moves from its rest position when a wave passes.
On a graph, the vertical axis (y-axis) is the amplitude of a waveform and this simply means that, it's measured vertically.
Mathematically, the amplitude of a wave is given by the formula;
x = Asin(ωt + ϕ)
Where;
x is displacement of the wave measured in meters.
A is the amplitude.
ω is the angular frequency measured in rad/s.
t is the time period measured in seconds.
ϕ is the phase angle.
A 117 kg horizontal platform is a uniform disk of radius 1.61 m and can rotate about the vertical axis through its center. A 62.5 kg person stands on the platform at a distance of 1.05 m from the center, and a 28.3 kg dog sits on the platform near the person 1.43 m from the center. Find the moment of inertia of this system, consisting of the platform and its population, with respect to the axis.
Answer:
I_syst = 278.41477 kg.m²
Explanation:
Mass of platform; m1 = 117 kg
Radius; r = 1.61 m
Moment of inertia here is;
I1 = m1•r²/2
I1 = 117 × 1.61²/2
I1 = 151.63785 kg.m²
Mass of person; m2 = 62.5 kg
Distance of person from centre; r = 1.05 m
Moment of inertia here is;
I2 = m2•r²
I2 = 62.5 × 1.05²
I2 = 68.90625 kg.m²
Mass of dog; m3 = 28.3 kg
Distance of Dog from centre; r = 1.43 m
I3 = 28.3 × 1.43²
I3 = 57.87067 kg.m²
Thus,moment of inertia of the system;
I_syst = I1 + I2 + I3
I_syst = 151.63785 + 68.90625 + 57.87067
I_syst = 278.41477 kg.m²
Momentum is a quantity that we say is typically _______________ in collisions.
A. Conserved
B. Lost
C. Disappeared
D. Gained
Momentum is a quantity that we can say is typically conserved in collisions.
Momentum is the quantity that that we see typically conserve in the collision,therefore the correct answer is the option A
It is the type of collision in which the total momentum as well as the kinetic energy on the system is conserved .The momentum before the collision is equal to the momentum after the collision in other words one can say in the elastic collision momentum of the quantity is conserved.
In the inelastic collision the momentum is conserved but the kinetic energy of the quantity is not conserved.
Momentum of a quantity is conserved irrespective of the type of collision whether it will be elastic collision or inelastic collision the momentum of the quantity will always be conserved.
Hence,we can say that momentum is the quantity that is conserved in collision,The correct answer for the given problem is option A.
Learn more about the collision and from here
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when an apple falls towards the earth the earth moves up to meet the apple. Is it true? If yes, why is the earth motion not noticeable ?
Answer:
Yes, this is true.
-- While the apple is falling, the same gravitational force acts on both the apple and the Earth.
-- The mass of the apple is somewhere in the neighborhood of 1/4 kg.
-- The mass of the Earth is about 5.972 x 10²⁴ kg.
-- Since the Earth has roughly 2.389 x 10²⁶ times as much mass as the apple has, the apple has roughly 2.389 x 10²⁶ greater acceleration than the Earth has, and moves roughly 2.389 x 10²⁶ times as far down as the Earth moves up, before they smack together.
-- That's why you don't notice the Earth's motion.
-- Also, you're standing on the Earth, moving up with it, toward the apple. Maybe it would be different if you were sitting on the apple, riding it down to the ground, and you were able to notice the motion of the ground coming up to meet you at a speed that's 0.00000000000000000000000000419 of YOUR speed.
Answer From Gauth Math
help me with this one
Answer:
Explanation:
2. a
3. c
1. Imagine a bowling ball with a mass of 5,0 kg that is dropped from a height of 100m,
a. At the moment the bowling ball is dropped it is at a height of 100m, What is its
potential energy?
b. At the moment the bowling ball is dropped, it is not yet moving. Therefore, its
kinetic energy is what?
c. What is the total of both potential and kinetic energy?
a.
Given,
height (h) = 100m
mass (m) = 5kg
acceleration due to gravitation (g) = 9.8ms^-2
Potential energy
= mgh
= 5kg × 9.8ms^-1 × 100m
= 4900 kgm²s^-2
= 4900 J
b.
Since the ball is not moving yet, its kinetic energy is 0.
c.
The total of potential and kinetic energy at every point of the journey is same, i.e., 4900 J.
Highlight two factors which shows that heat from the sun does not reach the earth surface by convection
Answer:
Explanation:
The heat from the Sun gets to the surface of the Earth by radiation and not by convection because:
i. Radiation does not require material medium for its propagation: Since the space between the Sun and Earth is a vacuum ( i.e it is an empty space), then the only method for the heat from to Sun to get to the Earth is by radiation. This method does not require a material medium, while convection is a method that requires material medium for its propagation.
ii. Radiation occurs without heating the intervening medium: During the propagation of the heat from the Sun to the Earth, the space between the two heavenly bodies is not heated up. Some fraction of the heat after hitting the surface of the Earth get reflected back into the Earth's atmosphere. While in convection, the medium would have been heated up in the process.
Describe the term of inertia with the respect of motion
Answer:
Inertia can be defined as the tendency of an object or a body to continue in its state of motion or remain at rest unless acted upon by an external force.
Explanation:
Motion can be defined as a change in the location (position) of a physical object or body with respect to a reference point.
This ultimately implies that, motion would occur as a result of a change in location (position) of an object with respect to a reference point or frame of reference i.e where it was standing before the effect of an external force.
Inertia can be defined as the tendency of an object or a body to continue in its state of motion or remain at rest unless acted upon by an external force.
Newton's First Law of Motion is also known as Law of Inertia and it states that, an object or a physical body in motion will continue in its state of motion at continuous velocity (the same speed and direction) or, if at rest, will remain at rest unless acted upon by an external force.
The inertia of an object such as a truck is greatly dependent or influenced by its mass; the higher quantity of matter in a trailer, the greater will be its tendency to continuously remain at rest.
In conclusion, inertia is applicable to all physical objects.
the weight of a body is 420 newton.calculate it's mass
Answer:
42g
Explanation:
the mass of a body is given by
m=weight/gravity
=420/10
=42
I hope this helps
Vector A has magnitude of 8units and makes an angle of 45° with the positive x-axis. Vector B also has the same magnitude of 8units and directed along the negative x-axis. Find a. The magnitude and direction of A+B b. The magnitude and direction of A-B
Answer:
Explanation:
Because vectors have direction and x and y components you can't just add them and say that their length is 16 because A is 8 units and so is B. What you're actually finding is the magnitude and direction of the vector that results from this addition. The magnitude is the length of the resultant vector, which comes from the x and y components of A and B, and the direction is the angle between the resultant vector and the positive x axis. To add the vectors, then, we need to find the x and y components of each. We'll do the x components of A and B first so we can add them to get the x component of C. Since x values are directly related to cos, the formula to find the x components of vectors is
[tex]V_x=Vcos\theta[/tex] which is the magnitude of the vector (its length) and the angle. Finding the x components of A:
[tex]A_x=8.0cos45[/tex] so
[tex]A_x=5.7[/tex] and for B:
[tex]B_x=8.0cos180[/tex] since the negative x axis is the 180 degree axis and
[tex]B_x=-8.0[/tex] If we add them, we get
[tex]C_x=-2.3[/tex]
Now onto the y components. The formula for that is almost the same as the x components except use sin instead of cos:
[tex]A_y=8.0sin45[/tex] so
[tex]A_y=5.7[/tex] and
[tex]B_y=8.0sin180[/tex] so
[tex]B_y=0[/tex] If we add them, we get
[tex]C_y=5.7[/tex]
Now for the final magnitude:
[tex]C_{mag}=\sqrt{(-2.3)^2+(5.7)^2}[/tex] and
[tex]C_{mag}=6.1 units[/tex] and now onto the direction.
The x component of C is positive and the y component is negative, which means that the direction has us at an angle is quadrant 2; we add 180 to whatever the angle is. Finding the angle:
[tex]tan^{-1}(\frac{C_y}{C_x})=(\frac{5.7}{-2.3})[/tex] = -68 + 180 = 112 degrees
The resultant vector of A + B has a magnitude of 6.1 and a direction of 112°
Do the same thing for subtraction, except if you're subtracting B from A, the direction that B is pointing has to go the opposite way. That means that A doesn't change anything at all, but B is now pointing towards 0.
[tex]A_x=5.7[/tex] (doesn't change from above)
[tex]B_x=8.0cos0[/tex] and
[tex]B_x=8.0[/tex] so
[tex]C_x=13.7[/tex] and
[tex]A_y=5.7[/tex] (also doesn't change from above)
[tex]B_y=8.0sin0[/tex] so
[tex]B_y=0[/tex] and
[tex]C_y=5.7[/tex] and for the magnitude:
[tex]C_{mag}=\sqrt{(13.7)^2+(5.7)^2[/tex] so
[tex]C_{mag}=15units[/tex] and for the direction:
[tex]tan^{-1}(\frac{5.7}{13.7})=23[/tex] and since both x and y components of C are in Q1, we add nothing.
And you're done!!!
Explain why some of the tree get detached from a tree if we vigorously shake it's Branch.
Answer:
When a tree is vigorously shaken, the branches of the tree come in motion but the leaves tend to continue in their state of rest due to inertia of rest. As a result of this, leaves get separated from the branches of the tree and hence fall down.
Answer:
When a tree is vigorously shaken, the branches of the tree come in motion moving left and right and shake the leaves off, that's why some of the tree got detached when we vigorously shake its branch.
Explanation:
Like I did in the answer section.
