Answer:
the time taken for the motor to lift the object is 21.17 s.
Explanation:
Given;
mass of the object, m = 45 kg
height through which the object was lifted, h = 9.0 m
electrical power used by the motor, P = 750 W
Efficiency of the electrical motor, n = 25% = 0.25
The electrical energy used by the motor in lifting the object is calculated as;
E = P x t
where;
t is the time taken for the motor to lift the object
E = 750 x t
E = 750t
The electrical energy converted by the motor to mechanical energy is calculated as;
P.E = 0.25(750t)
P.E = 187.5t
Recall, P.E = mgh
mgh = 187.5t
45 x 9.8 x 9 = 187.5t
3969 = 187.5t
t = 3969/187.5
t = 21.17 s
Therefore, the time taken for the motor to lift the object is 21.17 s.
Please solve for 15 points. Please don’t input a link.
Answer:
a). Single replacement.
Explanation:
Because one element replaces another element in a compound
A go-cart is traveling at 15 mi/hr. How long does it take the go-cart to travel 3 miles?
Answer:
12 min
Explanation:every 4 minutes is 1 mile
We have seen that the voltage of a concentration cell can be affected by the concentrations of aqueous components and/or temperature. The identity of the redox pair also affects the observed voltage of a concentration cell in a somewhat subtle way. Carefully consider the Nernst equation. Rank the redox pairs below from greatest (1) to smallest (3) voltage in a concentration cell, assuming equal values of T and Q for all cells. Assume multimeter leads are connected to that measured voltages are positive.
a. Copper metal/copper(l) ion
b. Aluminum/aluminum ion
c. Magnesium metal/magnesium ion
Answer:
1) Magnesium metal/magnesium ion
2) Aluminum/aluminum ion
3) Copper metal/copper(l) ion
Explanation:
The activity series is a series that shows the ease of reactivity of substances in an electrochemical cell.
The substances that are higher up in the series are more reactive in electrochemical cells.
Magnesium is the first element in the series that has the most negative redox potential then followed aluminium.
Hence, according to Nernst,
1) Magnesium metal/magnesium ion
2) Aluminum/aluminum ion
3) Copper metal/copper(l) ion
Acellus
What are harmful substances in the air,
soil, and water called?
A. pollutants
B. toxins
C. carcinogens
D. mutants
a disk of a radius 50 cm rotates at a constant rate of 100 rpm. what distance in meters will a point on the outside rim travel during 30 seconds of rotation?
Answer:
Wait lang po sandali po wait lang
Two protons move with uniform circular motion in the presence of uniform magnetic fields. Proton one moves twice as fast as proton two. The magnitude of the magnetic field in which proton one is immersed is twice the magnitude of the magnetic field in which proton two is immersed. The radius of the circle around which proton one moves is r. What is the radius of the circle around which proton two moves
Answer:
r₂ = 4 r
Explanation:
For this exercise let's use Newton's second law with the magnetic force
F = q v x B
bold letters indicate vectors, the magnitude of this expression is
F = q v B sin θ
in this case we assume that the angle is 90º between the speed and the magnetic field.
If we use the rule of the right hand with the positive charge, the thumb in the direction of the speed, the fingers extended in the direction of the magnetic field, the palm points in the direction of the force, which is towards the center of the circle, therefore the force is radial and the acceleration is centripetal
a = v² / r
let's use Newton's second law
F = ma
q v B = m v² / r
r = [tex]\frac{qB}{mv}[/tex]
Let's apply this expression to our case.
Proton 1
r = \frac{qB_1}{mv_1}
Proton 2
r₂ = [tex]\frac{q \ B_2}{m \ v_2}[/tex]
in the exercise indicate some relationships between the two protons
* v₁ = 2 v₂
v₂ = v₁ / 2
* B₂ = 2B₁
we substitute
r₂ = [tex]\frac{q \ 2B_1}{m \ \frac{v_1}{2} }[/tex]
r₂ = 4 [tex]\frac{qB_1}{mv_1}[/tex]
r₂ = 4 r
(Need help pls)!!!!!
Answer:
I assume they want answer A, but it's a silly question.
Explanation:
Well, if we assume that the girls are applying equal force, as they are the same size and strength (apparently also the same resolve etc.).
Equal force in opposite directions means the composite force is null. An object that no force is applied to continues moving in the same direction, so if the doll was moving somewhere, it would keep doing so, except all of this makes no sense the doll is not in gravityless vacuum what are we even talking about.
The answer A is the least ridiculous.
explain the refraction of light on a glass slab
Answer:
refraction is the change in direction of a wave passing from one medium to another or from a gradual change in the medium.
a train has an initial velocity of 30 m/s. If the train accelerates uniformly at a rate of 6.3 m/s ^ for 2.8 seconds what is the trains final velocity?
T
Answer:
the velocity is a second final to initial velocity of 39
6. The rate at which velocity changes is called
O speed
O direction
O acceleration
O displacement
If a 75 W lightbulb is 15% efficient, how many joules of light energy does the bulb produce every minute?
Answer:
1 W = 1 J / sec Definition of watt is 1 joule / sec
So if a bulb uses 75 J / sec it must use
75 J/s * 60 sec / min = 4500 J/min energy used by bulb
If bulb is 15% efficient then the light delivered is
P = 4500 J / min * .15 = 675 J / min
Pls quickly brainliest to the first to anwser
Answer:
8m/s^2
Explanation:
hope it helps........
Explanation:
you're supposed to know the formula of acceleration which is velocity of a time then you can solve the question
An object, with mass 64 kg and speed 14 m/s relative to an observer, explodes into two pieces, one 2 times as massive as the other; the explosion takes place in deep space. The less massive piece stops relative to the observer. How much kinetic energy is added to the system during the explosion, as measured in the observer's reference frame
Answer:
K_f = 1881.6 J
Explanation:
To solve this exercise, let's start by finding the velocities of the bodies.
We define a system formed by the initial object and its parts, with this the forces during the explosion are internal and the moment is conserved
initial instant. Before the explosion
p₀ = M v₀
final instant. After the explosion
p_f = m₁ v + m₂ 0
the moeoto is preserved
p₀ = p_f
M v₀ = m₁ v
v = [tex]\frac{m_1}{M}[/tex] v₀
in the exercise they indicate that the most massive part has twice the other part
M = m₁ + m₂
M = 2m₂ + m₂ = 3 m₂
m₂ = M / 3
so the most massive part is worth
m₁ = 2 M / 3
we substitute
v = ⅔ v₀
with the speed of each element we can look for the kinetic energy
initial
K₀ = ½ M v₀²
Final
K_f = ½ m₁ v² + 0
K_f = ½ (⅔ M) (⅔ v₀)²
K_f = [tex]\frac{8}{27}[/tex] (½ M v₀²)
K_f = [tex]\frac{8}{27}[/tex] K₀
the energy added to the system is
ΔK = Kf -K₀
ΔK = (8/27 - 1) K₀
ΔK = -0.7 K₀
K_f = K₀ + ΔK
K_f = K₀ (1 -0.7)
K_f = 0.3 K₀
let's calculate
K_f = 0.3 (½ 64 14²)
K_f = 1881.6 J
Which of these cubes absorb the most light?
Answera black cube or dark colors cause dark colors suck in heat
In a nuclear fusion reaction, atoms:
split apart.
combine.
explode.
cool down.
A mass MM uniform solid cylinder of radius RR and a mass MM thin uniform spherical shell of radius RR roll without slipping. If both objects have the same kinetic energy, what is the ratio of the speed of the cylinder to the speed of the spherical shell
Answer:
vcyl / vsph = 1.05
Explanation:
The kinetic energy of a rolling object can be expressed as the sum of a translational kinetic energy plus a rotational kinetic energy.The traslational part can be written as follows:[tex]K_{trans} = \frac{1}{2}* M* v_{cm} ^{2} (1)[/tex]
The rotational part can be expressed as follows:[tex]K_{rot} = \frac{1}{2}* I* \omega ^{2} (2)[/tex]
where I = moment of Inertia regarding the axis of rotation.ω = angular speed of the rotating object.If the object has a radius R, and it rolls without slipping, there is a fixed relationship between the linear and angular speed, as follows:[tex]v = \omega * R (3)[/tex]
For a solid cylinder, I = M*R²/2 (4)Replacing (3) and (4) in (2), we get:[tex]K_{rot} = \frac{1}{2}* \frac{1}{2} M*R^{2} * \frac{v_{cmc} ^{2}}{R^{2}} = \frac{1}{4}* M* v_{cmc}^{2} (5)[/tex]
Adding (5) and (1), we get the total kinetic energy for the solid cylinder, as follows:[tex]K_{cyl} = \frac{1}{2}* M* v_{cmc} ^{2} +\frac{1}{4}* M* v_{cmc}^{2} = \frac{3}{4}* M* v_{cmc} ^{2} (6)[/tex]
Repeating the same steps for the spherical shell:[tex]I_{sph} = \frac{2}{3} * M* R^{2} (7)[/tex]
[tex]K_{rot} = \frac{1}{2}* \frac{2}{3} M*R^{2} * \frac{v_{cms} ^{2}}{R^{2}} = \frac{1}{3}* M* v_{cms}^{2} (8)[/tex]
[tex]K_{sph} = \frac{1}{2}* M* v_{cms} ^{2} +\frac{1}{3}* M* v_{cms}^{2} = \frac{5}{6}* M* v_{cms} ^{2} (9)[/tex]
Since we know that both masses are equal each other, we can simplify (6) and (9), cancelling both masses out.And since we also know that both objects have the same kinetic energy, this means that (6) are (9) are equal each other.Rearranging, and taking square roots on both sides, we get:[tex]\frac{v_{cmc}}{v_{cms}} =\sqrt{\frac{10}{9} } = 1.05 (10)[/tex]
This means that the solid cylinder is 5% faster than the spherical shell, which is due to the larger moment of inertia for the shell.When a car makes a sharp left turn, what causes the passengers to move toward the right side of the car? *
A centrifugal force
B inertia
C centripetal acceleration
D centripetal force
B, the body at rest becomes reluctant to start moving or a body in motion becomes
reluctant and stop moving once in motion in a straight line
This photo shows a beam of light entering and exiting a piece of glass.
What happens when the light enters the glass?
A. The light is absorbed.
B. The light is reflected.
C. The light is scattered.
D. The light is refracted.
Answer:
D. The Light Is Refracted
Explanation:
<3
I’ll mark you as brinlist please help.
Answer:
245 divided by 5.14=47.6653696 or 47.66
Explanation:
If an athlete runs the triathlon of 10 km in 2 hours, what is her average speed in kilometers per hour?
Answer: 5 km per hour
Explanation:
if in 10 km there is 2 hours, then 10 divided by 2 is 5.
The Brazilian rain forest is an area with significant biodiversity. As the rain forest is replaced with agricultural land, it is reasonable to predict a reduction in -
Answers-
A: consumption of solar energy.
B: sustainability over time.
C: precipitation levels.
D: average daily temperature.
Answer:
Bb
Explanation:
a Ferris wheel with a diameter of 35 m starts from rest and achieves its maximum operational tangential speed of 2.3 m/s in a time of 15 s. what is the magnitude of the wheels angular acceleration?
b. what is the magnitude of the tangential acceleration after the maximum operational speed is reached?
(a) The magnitude of the wheels angular acceleration is 0.0088 rad/s².
(b) The magnitude of the tangential acceleration after the maximum operational speed is reached is 0.153 m/s².
Angular acceleration of the wheel
The angular acceleration of the wheel is calculated as follows;
α = ω/t
ω = v/r
α = v/(rt)
α = (2.3)/(17.5 x 15)
α = 0.0088 rad/s²
Tangential acceleration of the wheela = v/t
a = (2.3)/15
a = 0.153 m/s²
Learn more about angular acceleration here: https://brainly.com/question/25129606
#SPJ6
When you look at the backside of a shiny teaspoon held at arm's length, do you see yourself upright or upside down? (b) When you look at the other side of the spoon, do you see yourself upright or upside down? Assume in both cases that the distance between you and the spoon is greater than the focal length of the spoon.
Answer:
a) The back spoon gives a right image (upright)
b) the front gives an inverted image
Explanation:
The spoon is a curved metallic object, when we see ourselves from the back we have a convex mirror, in this type of mirror when the law of reflection is applied the rays diverge therefore the eye-brain system forms the image with the prolongation of the rays, therefore the image is straight and smaller than the object.
When we look through the deep side of the spoon, we have a concave mirror and as the object (we) is further away than the distance, the rays converge to a point, so the image is real, inverted smaller than the object.
In summary.
a) The back spoon gives a right image (upright)
b) the front gives an inverted image
What is known as the amount of mass in
a given volume?
A. density
B. pressure
C. surface tension
D. mass pressure
A dog runs 51 m west to fetch a ball and brings it back only 27 m before stopping.
The total displacement of the dog is:
A uniform magnetic field is in the positive z direction. A positively charged particle is moving in the positive x direction through the field. The net force on the particle can be made zero by applying an electric field in what direction
Answer:
We apply an electric field in the negative y direction
Explanation:
Since A uniform magnetic field is in the positive z direction and A positively charged particle is moving in the positive x direction through the field, the magnetic force acting on the positively charged particle is in the positive y direction according to Fleming's right-hand rule.
For the net force on the particle to be zero, we apply an electric field in the negative y direction to create an electric force on the positively charged particle, so as to cancel out the magnetic force.
Which change will always result in an increase in the gravitational force between two objects?
O increasing the masses of the objects and increasing the distance between the objects
O decreasing the masses of the objects and decreasing the distance between the objects
O increasing the masses of the objects and decreasing the distance between the objects
• decreasing the masses of the objects and increasing the distance between the objects
Answer:
increasing the masses of the objects and decreasing the distance between the objects
Explanation:
Balance the equation by choosing the correct coefficient numbers in the drop down menus.
[Select]
SO2 +
[Select]
VH₂ →
[Select]
S +
[ Select]
H20
It is suggested you write this on scratch paper and balance it before choosing your answers :)
Answer:
SO₂ + 2H₂ —> S + 2H₂O
The coefficients are: 1, 2, 1, 2
Explanation:
SO₂ + H₂ —> S + H₂O
The above equation can be balance as follow:
SO₂ + H₂ —> S + H₂O
There are 2 atoms of O on the left side and 1 atom on the right side. It can be balance by writing 2 before H₂O as shown below:
SO₂ + H₂ —> S + 2H₂O
There are 2 atoms of H on the left side and 4 atoms the right side. It can be balance by writing 2 before H₂ as shown below:
SO₂ + 2H₂ —> S + 2H₂O
Now, the equation is balanced.
The coefficients are: 1, 2, 1, 2
volcano has both useful and harmful effects give reason
Answer:
harmful effects
1. that will cause air pollution
2. that will destroy our earth
Answer:
useful effects of volcano are :-
it makes soil fertile it provides valuable nutrients for the soilharmful effects of volcano are:-
it makes air polluted it destroy the environment .hope it is helpful to you ☺️
a 7 kg object moving 10 m/s Right collides with a 14 kg object at rest. If after the collision the 7kg object is at rest and the 14 kg object is moving, what is the velocity of the 14 kg object after the collision?
Answer:
v2(final)=5 m/s
Explanation:
we are going to use the conservation of momentum here
m1*v1(initial)+m2*v2(initial)=m1*v1(final)+m2v2(final)
m1=7 kg v1(initial)=10 m/s
m2=14 kg v2(initial)=0 m/s (bc initially it is at rest)
v1(final)= 0 m/s (m1 stops moving after the collision)
v2(final)=?
7*10+14*0=7*0+14*v2(final)
70=14v2(final)
v2(final)=70/14 m/s=5 m/s