Answer:
Efficiency of a machine is 90% this means that the total energy produced to the machine only 90% is useful and given as a output.
Machines are not 100% efficient because some of the work done by a machine is used to overcome friction
what can be done to increase speed of rotation of a DC motor
Answer: There are multiple options:
By varying the supply voltage.
By varying the flux, and by varying the current through the field winding.
By varying the armature voltage, and by varying the armature resistance.
Helpful Link:
https://www.elprocus.com/what-are-the-best-ways-to-control-the-speed-of-dc-motor/
If the velocity of a motorcycle increases from 30 mis too 50m/s in 10 seconds what will be the acceleration of motorcycle?
Answer:
2 m/s^2
Explanation:
a = ∆v / ∆t
a = (50 - 30) / 10
a = 20 / 10
a = 2 m/s^2
acceleration = u-v/t
50-30/10
=2m/s
what will be the effect on the acceleration due to gravity of the earth if it is compressed to a the size the moon?
Answer:
it gravitional pull on earth will increased becauste it is compress to a form of moon which is comperatively smaller so the gravitonal pull on per cm of earth will incrased so we can say that there will be change in acceleration due to gravity
physics as a subject involves measurement and estimation,giving examples of everyday life situations, explain the meaning and what is done in each case
Answer:
57
Explanation:
(This is for other people with this Question i hope you find this when you need help) Need answer for this Help!!!
Question 7 of 20 You plan to use a slingshot to launch a ball that has a mass of 0.025 kg. You want the ball to accelerate straight toward your target at 19 m/s2. How much force do you need to apply to the ball? O A. 19.03 N OB. 0.48 N O C. 4.51 N D. 760.00 N
Answer:
0.48N
Explanation:
according to the second law of motion
force=mass×acceleration
the mass in this question is 0.025,the acceleration 19
therefore f=0.025×19
=0.48N
I hope this helps
Electricity flows from
positive to positive
negative to positive
negative to negative
positive to negative
Answer:
is it from positive to negative am I right tell me if I am wrong
Answer:
positive to negative
The flow of electric current is similar to the flow of water which is from higher level to lower level.
The electric current flow from higher potential region(positive* low concentration of electron) to lower potential region(negative*high concentration of electron)
A rocket travels 1.3 km in 62 ms. What is its average speed in m⋅s−1? Do not give your answer in scientific notation. The answer should be given to 2 significant figures.
Answer:
Average speed = 0.35 m/s
Explanation:
Given the following data;
Distance = 1.3 Km
Time = 62 minutes
To find the average speed in m/s;
First of all, we would convert the quantities to their standard unit (S.I) of measurement;
Conversion:
1.3 kilometres to meters = 1.3 * 1000 = 1300 meters
For time;
1 minute = 60 seconds
62 minutes = X
Cross-multiplying, we have;
X = 62 * 60
X = 3720 seconds
Now, we can calculate the average speed in m/s using the formula;
[tex] Speed = \frac {distance}{time} [/tex]
[tex] Speed = \frac {1300}{3720} [/tex]
Average speed = 0.35 m/s
Explanation of the physics involved i the northern lights(aurora borealis) why can't it occur in mire southerns latitudes?
Answer:
The northern lights come from the interaction of electrically charged particles given off by the Sun surface during solar storms and the Earth's magnetic field which is pointed in the northern to southern poles of the Earth. Therefore, the charged particles that travel through millions of miles from the Sun to the Earth accelerate towards the magnetic poles and appear as the northern (and southern) lights
Boreal is an adjective word for the north or northern regions. In the southern latitudes, in the southern hemisphere, the phenomenon is called aurora australis (australis is the adjective for 'of the south')
Explanation:
How is the potential difference same in capacitors arranged in parallel combination?
Answer:
Potential difference across capacitors in parallelTwo or more capacitors are said to be connected in parallel if each one of them is connected across the same two points. In a parallel combination of capacitors potential difference across each capacitor is same but each capacitor will store different charge.
Why does the Earth exert a gravitational force on objects on its surface?
A. It has an atmosphere,
B. It has mass
C. It has a magnetic field.
D. It is so dense.
Answer:
B. It has mass
Explanation:
The Newtons Universal gravitacion law is : F = G.[tex]\frac{m1 m2}{d^{2} }[/tex] , where F is the force exerted , m1 and m2 are the earth's mass and the object's mass, d is the distance and G the gravitacional constant. Comparing to the options we can say that the Earth exerts a gravitational force on objects on its surface because of its mass.
state one similarity and one difference of sound of frequency 750Hz and ultrasound
Explanation:
Ultrasound refers to sound waves having frequencies greater than the frequency range limit. Ultrasound has the same physical qualities as "regular" (audible) music, except that individuals cannot hear it. Ultrasound devices use frequencies ranging from 20 kHz to a few gigahertz.
The frequencies of ultrasound utilised in clinical settings are generally between 2 and 12 MHz. Shorter wavelengths have a larger penetration depth into the body but less resolution; longer wavelengths have a greater depth of penetration but have a restricted depth of penetration.
An airplane flying at 116 m/s. E, is accelerated uniformly at the rate of 9.2 m/s2, E, for 13 s. What is its final velocity in m/s?
Answer:
235.6m/s
Explanation:
you have to use one of the kinematic formulas the best that suits the question given in this case you can use v=u+at.since the time, acceleration and initial velocity have been given in the question
v=116+(9.2)13^2
v=116+119.6
=235.6m/s
I hope this helps
magnetised hacksaw blade is cut into two pieces..can there be two poles on both sides??
Answer:
yes
Explanation:
because the dipoles are not arrange the same way they were in the full hacksaw
A horse is running on a circular path with constant speed but its direction is changing at every point. It is
Answer:
accelerating.
Explanation:
A horse is running on a circular path with constant speed but its direction is changing at every point. Thus, it is accelerating.
hai vật chuyển động ngược chiều qua A với B cùng lúc, ngược chiều để gặp nhau . Vật qua A có vận tốc 10m/s, qua B có vận tốc 15m/s. AB=100m
a, lấy trục tọa độ là đường thẳng AB, gốc tọa độ ở B , có chiều dương từ A sang B , gốc thời gian là lúc chúng cùng đi qua A và B . Lập phương trình chuyển động của hai xe
b, xác định vị trí , thời điểm 2 xe gặp nhau
c, xác định vị trí , thời điểm 2 xe cách nhau 25m
Answer:
wah wats this again
Explanation:
Bhai mujhe samaj nahi ah Raha
Kya Bolne Chahtaa hu tum
Answer:
bạn vẽ ra rồi làm
Explanation:
D=12000 m
T= 30min
V=?
Ayudenme en este ejercicio xfa
En m/min y en Km/h
the diameter of circular park is 80 m find its area
valancy of an atom is +2. what does it mean.
Answer: I hope you find it useful
Explanation: Group 2 elements have two valence electrons. The two valence electrons are easily lost in the formation of chemical bonds. Once the two electrons are lost, the atom then has a full outer shell and is therefore more stable.
so, if an atom has valency 2 , then it means that the atom can combine with 2 other atoms .
A spacecraft orbits the Earth at height of 1600km. Calculate the escape velocity for the spacecraft.
[G= 6.67×10^-11Nm^2kg^-2, mass of the Earth= 5.97×10^24kg, radius of the Earth= 6.37×10^6m]
Answer:
what do u need help with
Explanation:
Calculate the escape velocity for the spacecraft. [G= 6.67×10^-11Nm^2kg^-2, mass of the Earth= 5.97×10^24kg, radius of the Earth= ...
Hydroplaning causes your front wheels to actually leave the pavement and the wheels are riding on a thin layer of water. This lack of traction with the pavement takes away your control of the vehicle. To regain control of your vehicle you should___________.
Answer: Remove your foot from the gas pedal and slow down
Explanation:
Hydroplaning also refers to aquaplaning and this refers to the scenario whereby there's a layer of water that builds between the tyres of a car and the surface of the road which then brings about a loss of traction which eventually leads to a situation whereby the car doesn't respond to control inputs.
This lack of traction with the pavement takes away your control of the vehicle and to regain control of the vehicle, one should remove your foot from the gas pedal and slow down.
What is the electric potential of a 4.5x10^-5 C charge that has an electric potential energy of 0.027 J?
Answer:
600 volts
Explanation: just do 4.5x10^-5c lol i hope this helps if it dont im so sorry
A student project is required to be portable and hand held. It requires 6 V DC power at a current of 150 mA. The batteries for the power supply must last for a minimum of 7 hours of continuous operation. NiMH rechargeable batteries in AA size are to be used. A) How many batteries are needed
Answer:
a. 5 batteries b. 1050 mAh
Explanation:
Here is the complete question
A student project is required to be portable and hand held. It requires 6 V DC power at a current of 150 mA. The batteries for the power supply must last for a minimum of 7 hours of continuous operation. NiMH rechargeable batteries in AA size are to be used. A) How many batteries are needed? B) What mAh capacity should the batteries have?
Solution
A) How many batteries are needed?
Since the nominal voltage for a single NiMH battery is 1.2 V per battery and we require 6V DC power, we combine the batteries in series to obtain a total voltage of 6 V. The number of batteries required, n = total voltage/voltage per cell = 6V/1.2V per battery = 5 batteries
So, the number of batteries needed is 5.
B) What mAh capacity should the batteries have?
Since the batteries are in series, they would each deliver a current of 150 mA. Since we require a current of 150 mA for 7 hours, the number of milliampere-hours capacity mAh of batteries required is Q = It where I = current = 150 mA and t = time = 7 hours.
So, Q = It = 150 mA × 7 h = 1050 mAh.
So, the batteries should have a mAh of 1050 mAh
During which step of the scientific method does a scientist determine
whether the hypothesis was supported?
A. Perform the experiment
B. Collect data
C. Draw conclusions
D. Design an experiment
SUBMN
PREVIOUS
Answer:
A
in performing the experiment the hypothesis is proved wrong or correct prediction , meaning of prediction is guessing,
hypothesis the second stage of scientific method , scientist predict or guess the answer to the problem ,
Experiment the third stage of scientific method
scientist examine the ways
"Perform the experiment" is the step of the scientific method where a scientist determines whether the hypothesis was supported.
What step of the scientific method is used to prove if the hypothesis is accepted or rejected?In the scientific method, experiments (often with controls and variables) are devised to test hypotheses. In the scientific method, analysis of the results of an experiment will lead to the hypothesis being accepted or rejected.
How do scientists determine whether a hypothesis is correct?The basic idea of a hypothesis is that there is no predetermined outcome. For a solution to be termed a scientific hypothesis, it has to be an idea that can be supported or refuted through carefully crafted experimentation or observation.
Learn more about the hypothesis here https://brainly.com/question/11555274
#SPJ2
What is the right hand rule for magnetic Force?
Answer:
The right hand rule states that, to find the direction of the magnetic force on a positive moving charge, the thumb of the right hand point in the direction of v, the fingers in the direction of B, and the force (F) is directed perpendicular to the right hand palm.
Explanation:
pls mark brainliest
Hope this helps u
hai điện tích q1 =-2.10^(-8), q2=1,8.10^(-8) đặt tại A và B trong không khí,AB=8cm. Một điện tích q3 đặt tại C. 1, C ở đâu để q3 cân bằng
Answer:
Đáp án là vị trí để đặt q3 tại vị trí cân bằng là cách A một đoạn 0,0411 m
và nằm trong AB
Explanation:
Do q1 và q2 trái dấu nên q3 nằm trong
gọi r1 là vị trí từ A đến q3 suy ra r2=0.08-r1
Vị trí cân bằng nên [tex]\frac{q1}{r1^{2} }[/tex] = [tex]\frac{q2}{(0.08-r1)^{2} }[/tex]
Given that on Earth, gravity causes an acceleration of 9.8 m/s2, what is an acceleration of 7 g?
Answer:
68.6 m/s^2
Explanation:
1 g = 9.8 m/s^2
so
7 g × 9.8m/s^2 = 68.6
The hair dryer has a plastic case so there is no need for an earth wire connection in the plug ,explain why the hair dryer is still safe to use.
Answer:
plastics are unable to conduct electricity and heat due to there being no free flowing electrons, meaning they are safe to use.
Explanation:
7. A thin wire was wound 30 times closely over a boiling tube. The total length of the windings as measured was found to be 6.3mm. Determine the diameter of the wire .
Answer:
Diameter of wire = 0.00021 meters
Explanation:
Given the following data;
Number of windings = 30
Length of windings = 6.3 mm to meters = 0.0063 meters
To find the diameter of the wire, we would use this mathematical expression;
Length of windings = number of windings * diameter of wire
Substituting the values into the expression, we have;
0.0063 = 30 * diameter of wire
Diameter of wire = 0.0063/30
Diameter of wire = 0.00021 meters
what is the direction of magnetic lines of force outside the magnet
please mark me as brainiest p
Explanation:
Magnetic lines of force are closed curves. C) Outside the magnet their direction is from north pole to south pole and inside the magnet these are from south to north pole.
A uniform, solid sphere of radius 2.50 cm and mass 4.75 kg starts with a purely translational speed of 3.00 m/s at the top of an inclined plane. The surface of the incline is 2.75 m long, and is tilted at an angle of 22.0∘ with respect to the horizontal. Assuming the sphere rolls without slipping down the incline, calculate the sphere's final translational speed v2 at the bottom of the ramp.
Answer:
The final translational seed at the bottom of the ramp is approximately 4.84 m/s
Explanation:
The given parameters are;
The radius of the sphere, R = 2.50 cm
The mass of the sphere, m = 4.75 kg
The translational speed at the top of the inclined plane, v = 3.00 m/s
The length of the inclined plane, l = 2.75 m
The angle at which the plane is tilted, θ = 22.0°
We have;
[tex]K_i[/tex] + [tex]U_i[/tex] = [tex]K_f[/tex] + [tex]U_f[/tex]
K = (1/2)×m×v²×(1 + I/(m·r²))
I = (2/5)·m·r²
K = (1/2)×m×v²×(1 + 2/5) = 7/10 × m×v²
U = m·g·h
h = l×sin(θ)
h = 2.75×sin(22.0°)
∴ 7/10×4.75×3.00² + 4.75×9.81×2.75×sin(22.0°) = 7/10 × 4.75×[tex]v_f[/tex]² + 0
7/10×4.75×3.00² + 4.75×9.81×2.75×sin(22.0°) ≈ 77.93
∴ 77.93 ≈ 7/10 × 4.75×[tex]v_f[/tex]²
[tex]v_f[/tex]² = 77.93/(7/10 × 4.75)
[tex]v_f[/tex] ≈ √(77.93/(7/10 × 4.75)) ≈ 4.84
The final translational seed at the bottom of the ramp, [tex]v_f[/tex] ≈ 4.84 m/s.
