Question 21 of 25
Barry slides across an icy pond. The coefficient of kinetic friction between his
shoes and the ice is 0.15. If his mass is 83 kg, what is the force of friction
acting on him
O A 352 N
O B. 122 N
C. 1150 N
O D. 813N
Answer:
B. 122N
Explanation:
f = 0.15 x 83 x 9.8 = 122.01
f = 122N
As light from a star spreads out and weakens, do gaps form between the photons?
Answer:
There are no gaps in space between the photons as they travel. If you look at light as a wave, then there no gaps unless specifically placed there on purpose. ... The light from a distance star indeed spreads out and weakens as it travels, but this just reduces the wave strength and does not introduce gaps.
Suppose a piece of food is on the edge of a rotating microwave oven plate. Does it experience nonzero tangential acceleration, centripetal acceleration, or both when: (a) The plate starts to spin
Answer:
the only acceleration it has is radial (centripetal)
Explanation:
The microwaves plate rotates at a constant speed after a very short period of acceleration.
Therefore we can apply Newton's second law
F = m a
where the acceleration is centripetal
a = v2 / r = w2 r
therefore as it rotates constant speed it cannot have a tangential acceleration since it changes the modulus of the speed.
Consequently the only acceleration it has is radial (centripetal)
Spring balance measures weight, not the mass of a body.
Answer:
That is true and is easily explained by the next equation:
W= m*g
where
W= Weight
m=mass
g= gravitational acceleration
so, if you use a spring balance in another planet with a different gravitational acceleration the measured weight will be different.
the velocity is always _____ to the line of a circle
Answer:
The velocity is always tangent to the line of a circle .
Explanation:
When an object moves in a circular path, its motion is called the circular motion. The speed of the object is constant at each and every point in such motion while the velocity changes due to change in direction.
In a circular motion, the direction of velocity is always tangent to the circle. At each and every point, its direction is found tangentially.
Mustang Sally just finished restoring her 1965 Ford Mustang car. To save money, she did not get a new battery. When she tries to start the car, she discovers that the battery is dead (an insufficient or zero voltage difference across the battery terminals) and so she will need a jump start. Here is how she accomplishes the jump start:
Explanation:
To jump start she needs
1. Jumper cables
2. Power source/jump box/ portable batteries.
The positive end of the jump cable will be connected to terminal of the car battery and the jump box, likewise the negative terminal to complete the circuit for a successful jump start to be accomplished
A ball is launched from the ground with a horizontal speed of 30 m/s and a vertical speed of 30 m/s. When will the ball hit the ground again? A. 4 s B. 6 s C. 3 s D. 5 s
Answer:
B. 6 s
Explanation:
Given in the y direction:
Δy = 0 m
v₀ = 30 m/s
a = -10 m/s²
Find: t
Δy = v₀ t + ½ at²
0 m = (30 m/s) t + ½ (-10 m/s²) t²
0 = 30t − 5t²
0 = 5t (6 − t)
t = 6
A ball is launched from the ground with a horizontal speed of 30 m/s and a vertical speed of 30 m/s, the ball will hit the ground again at approximately t = 6 seconds. The correct option is B.
We can examine the ball's vertical motion to predict when it will strike the ground once more.
h = v0t + (1/2)g[tex]t^2[/tex]
0 = 30t + (1/2)(9.8) [tex]t^2[/tex]
Simplifying the equation:
4.9 [tex]t^2[/tex] + 30t = 0
Factorizing the equation:
t(4.9t + 30) = 0
Solving for t in 4.9t + 30 = 0:
4.9t = -30
t = -30 / 4.9
t ≈ -6.1
Since time cannot be negative in this context, we discard the negative solution.
Therefore, the ball will hit the ground again at approximately t = 6 seconds.
Thus, the correct answer is B. 6 s.
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differentiate between earthworm and housefly
Answer:
Earthworm lives in the soil, eats the soil which has organic matter such as decaying vegetation or leaves and crawls. While housefly lives in dirty places, feeds on faeces and flies.
Hope I get a brainliest answer.
Three resistors, A, B, and C, are connected in parallel and attached to a battery, with the resistance of A being the smallest and the resistance of C the greatest. Which resistor carries the highest current?
Answer:
Resistor A
Explanation:
Resistors A, B and C are connected in parallel to a battery of voltage represented by V.
Since they are in parallel, the same voltage, V, passes across the three of them.
And from Ohm's law, the voltage (V) through a resistor is the product of the current (I) flowing through it and the resistance (R) of the resistor. i.e
V = I x R
=> I = [tex]\frac{V}{R}[/tex]
Therefore, assuming the values of the resistances of resistors A, B and C are A, B and C respectively,
(i) the current, [tex]I_{A}[/tex] through A is
[tex]I_{A}[/tex] = [tex]\frac{V}{A}[/tex]
(ii) the current, [tex]I_{B}[/tex] through B is
[tex]I_{B}[/tex] = [tex]\frac{V}{B}[/tex]
(iii) the current, [tex]I_{C}[/tex] through C is
[tex]I_{C}[/tex] = [tex]\frac{V}{C}[/tex]
From the foregoing, it can be deduced that the current is inversely proportional to the resistance. Therefore, the higher the resistance, the lower the current. Consequential of this, the resistor that carries the highest current is the one with the smallest resistance, which is A
Resistor A
Given:
Resistors A, B and C are connected in parallel to a battery of voltage represented by V.
Since they are in parallel, the same voltage, V, passes across the three of them.
Ohm's law:
It states that voltage (V) through a resistor is the product of the current (I) flowing through it and the resistance (R) of the resistor. i.e.
V = I x R
⇒ I = V/R
Therefore, assuming the values of the resistances of resistors A, B and C are A, B and C respectively,
(i) the current, through A is
[tex]I_A=\frac{V}{A}[/tex]
(ii) the current, through B is
[tex]I_B=\frac{V}{B}[/tex]
(iii) the current, through C is
[tex]I_C=\frac{V}{C}[/tex]
From the Ohm's law we can say that the current is inversely proportional to the resistance.
Therefore, higher the resistance, the lower is the current.
It is given that resistance of A being the smallest, thus is will carries the highest current.
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A rocket moves through empty space in a straight line with constant speed. It is very far from any star or planet. Under these conditions, the force that must be applied to the rocket in order to sustain its motion is
Answer:
analysis the force is zero
Explanation:
Let's apply Newton's second law
F = m a
In this equation we see that the force is directly related to the acceleration, as they indicate that the rocket is far from any planet or star has no force applied to it, therefore they also relate it to zero.
Change we can analyze the exercise with Newton's first law, which indicates that an object maintains its constant speed in a straight line has no forces applied to it.
In either analysis the force is zero
Bruno the bat flies at a speed of 0.5 m/s in circle of radius 1 m. What is his acceleration?
Very urgent pls help
Answer:
Acceleration is 0.25m/s^2
Explanation:
Given the following :
Speed = 0.5m/s
Radius(r) of circle = 1m
Acceleration round a circular path is given as :
a = v^2 / r
Where
a = acceleration of the body
v = speed / velocity
r = radius
Therefore,
a = v^2 / r
a = (0.5)^2 / 1
a = 0.25m/s^2
If two people are running at the same speed in the same direction. One person is one meter ahead of the other. The person in front throws a ball to the person slightly behind. As seen by an observer at rest on the ground, is it possible that the ball looks as if it was thrown forward
Answer:yes
Explanation:
Select the type of energy involved in each step. You turn on the burner of a gas stove. The gas ignites. The gas warms the water in the pan.
Answer:
You turn on the burner of a gas or stove - mechanical energy.
The gas ignites - Chemical energy.
The gas warms the water in the pan - Thermal energy.
Na (g) + 2HCl (g) -> H2 (g) + 2NaCl (s) is a balanced equation? True or false?
Answer:
False, the given equation is not balanced.
Explanation:
The given equation is:
Na(g) + 2HCl(g) → H₂(g) + 2NaCl(s)
And it is not balanced, the number of atoms of Na is not the same on both sides of the equation.
The balanced equation is:
2Na(g) + 2HCl(g) → H₂(g) + 2NaCl(s)
Now, the given equation is balanced, we have the same number of atoms on both sides of the equation.
Therefore, the answer is false, the given equation is not balanced.
I hope it helps you!
What is the change in internal energy if 60 J of heat are released from a
system and 20 J of work is done on the system? Use AU = Q-W.
Answer:
60 J of heat are released from the system: Q=-60 J
20 J of work is done on the system: W=-20 J
∆U=Q-W
∆U=-60-(-20)
∆U=-40 J
Explanation:
If the heat is released from the system, Q should be negative.
If the heat is gained by the system, Q should be positive.
If the work is done on the system, W should be negative.
If the work is done by the system, W should be positive.
Please help me with this question ASAP.
In a a potentiometer circuit, a 1m long potentiometer wire PQ of resistance 10 ohms is connected in series with a cells of e.m.f. 9V with internal resistance 3 ohms Calculate:
i The p.d. across PQ
ii. The e.m.f. of a cell which has a balance point of 75cm.
Answer:
i. 6.923 V
ii. The e.m.f. = 22.5 V
Explanation:
i. The given parameters are;
Length of potentiometer = 1 m
The resistance of the potentiometer = 10 Ω
The e. m. f. of the attached cell = 9 V
The current, I flowing in the circuit = e. m. f/(Total resistance)
The current, I flowing in the circuit = 9 V/(10 + 3) = 9/13 A
The potential difference, p.d. across the 1 m potentiometer wire = I × Resistance of the potentiometer wire
The p.d. across the potentiometer wire = 9/13×10 = 90/13 = 6.923 V
ii) Given that the 1 m potentiometer wire has a resistance of 10 Ω, 75 cm which is 0.75 m will have an e.m.f. given by the following relation;
[tex]\dfrac{E}{R_{balance}} = \dfrac{V}{R_{cell}}[/tex]
Where:
E = e.m.f. of the balance point cell
[tex]R_{balance}[/tex] = Resistance of 75 cm of potentiometer wire = 0.75×10 = 7.5 Ω
[tex]R_{cell}[/tex] = Resistance of the cell in the circuit = 3 Ω
V = e.m.f. attached cell = 9 V
[tex]\dfrac{E}{7.5} = \dfrac{9}{3}[/tex]
E = 7.5*3 = 22.5 V
The e.m.f. = 22.5 V
a boy has a mass of 80kg on earth where g= 10N/kg a) what is his mass on the moon b ) find his weight on the moon ( g= 10N/kg)
Explanation:
mass on moon is also 80kg because it doesn't differed according to place.
I think we can't calculate weight because there is no gravity in moon
Answer 80kg
Explanation Mass is constant in every corner of universe. It's better if u have asked about weight on moon. It is same in both earth and moon.
A student focussed the image of a candle flame on a white screen using a convex lens. He noted down the position of candle, screen and the lens as under Position of candle = 12.0 cm Position of convex lens = 50.0 cm Position of the screen = 88.0 cm i.What is the focal length of the convex lens? ii. Where will the image be formed if he shifts the candle towards the lens at a position of 31.0 cm? iii. What will be the nature of the image formed if he further shifts the candle towards the lens? iv. Draw a ray diagram to show the formation of the image in case (iii) as said above.
Answer:
Explanation:
Object distance = distance between object and lens
u = 50 - 12 = 38 cm
image distance v = 88 - 50 = 38 cm
i )
using lens formula
1 / v - 1 / u = 1 / f
1 / 38 - 1 / - 38 = 1/f
2 / 38 = 1 / f
f = 19 cm
ii ) So object is placed at 2 f or at the center of curvature of the lens .
If object distance is changed to 50 - 31 = 19 cm
using lens formula
1 / v - 1 / u = 1 / f
1 / v + 1 / 19 = 1/19
1 / v = 0
v = infinity
It is so because now the object is placed at the focal distance
iii )
If object further shifts towards the lens , then virtual image of object will be formed behind the lens which will be larger than object .
The governor of state A earns $53,745 more than the governor of state B. If the total of their salaries is $289,405, find the salaries of each.
Answer:
Sa is the salary of the governor of state A
Sb is the salary of the governor of state A
"The governor of state A earns $53,745 more than the governor of state B. "
This means that:
Sa = Sb + $53,745
"If the total of their salaries is $289,405,"
means that:
Sa + Sb = $289,405
Then we have two equations:
Sa = Sb + $53,745
Sa + Sb = $289,405
Now, we can replace the first equation into the second equation:
(Sb + $53,745) + Sb = $289,405
2*Sb = $289,405 - $53,745 = $235,660
Sb = ($235,660)/2 = $117,830
and:
Sa = Sb + $53,745 = $117,830 + $53,745 = $171,575
Governor of state A earns: $171,575
Governor of state B earns: $117,830
Letícia leaves the grocery store and walks 150.0 m to the parking lot. Then, she turns 90° to the right and walks an additional 70.0 m to her car. What is the magnitude of the displacement of her car from the grocery store exit?
Answer:
165.529454
Explanation:
According to the Pythagorean Theorem for calculating the lengths of a right angle triangle's sides, a^2 + b+2 = c^2, where c is the longest side (and the side opposing the right angle). So in your case it would be 150*150 + 70*70 = 27400. And √ 27400 is your answer.
the velocity is always _____ to the line of a circle
Answer:
tangent
Explanation:
hope it helps
Answer:
the answer is tangent
Explanation:
tangent means a straight line or plane that touches a curve or curved surface at a point, but if extended does not cross it at that point.
hope this helps please like and heart this answer and give 5 stars and brainliest pls i beg u thx!!! : )
The large-scale distribution of galaxies in the universe reveals Group of answer choices a smooth, continuous, and homogenous arrangement of clusters large voids, with most of the galaxies lying in filaments and sheets a large supercluster at the center of universe a central void with walls of galaxies at the edge of the universe
Question
The large-scale distribution of galaxies in the universe reveals
A) a smooth, continuous, and homogenous arrangement of clusters
B) large voids, with most of the galaxies lying in filaments and sheets a large supercluster at the center of the universe
C) a central void with walls of galaxies at the edge of the universe
Group of answer choices
Answer:
The correct answer is B)
Explanation:
The universe is arranged in a filamentary structure. Filamentary structures are very large. They are the largest kind of structures in the universe and comprise mostly of galaxies that are held together by gravity.
The structures found within Galaxy filaments have thread-like qualities spanning 52 to 78.7 megaparsecs h⁻¹ in lenght.
Other phenomena associated with the nature fo the universe is the existence of void spaces.
Cheers!
A 20.0 Ohm and 60.0 Ohm resistor
are connected in series to a 9.00 V
battery. What is the voltage drop
across the 20.0 Ohm resistor?
(Hint: How much current flows
across it?)
(Unit = V)
Answer:
2.25 V
Explanation:
The equivalent resistance is:
R = 20.0 Ω + 60.0 Ω
R = 80.0 Ω
The current is:
V = IR
9.00 V = I (80.0 Ω)
I = 0.1125 A
The voltage drop across the 20.0 Ω resistor is:
V = IR
V = (0.1125 A) (20.0 Ω)
V = 2.25 V
WILL MARK U AS BRAINLIEST...... An aeroplane is taking off with a velocity of 360 km/h at an angle of 30° with the horizontal. find its horizontal and vertical componnent velocities.
Answer:
x=180√3. or 311.7 and y= 180km/h
Explanation:
y= sin30° × 360km/h
y= 0.5 × 360km/h
y= 180km/h
x=cos30° × 360 km/h
x=√3/2*360km/h
x=180√3. or 311.7
Two runners start at a distance of 10 miles from each other. They run towards each other at a constant velocity of 5 mph. A fly takes off from runner one’s nose at time zero. The fly has a constant velocity of 20 mph and flies between the runners. Find the total distance that the fly has traveled when the runners collide.
Answer:
The fly will travel 20 miles before the runners collide with each other.
Explanation:
Since the runners are both traveling at the same speed, they will meet and collide in the exact middle of each other which is 5 miles away from their starting point. Since they are traveling at 5 mph, it will take exactly one hour before they collide. The fly is going 20 mph so it will travel 20 miles before the runners collide in one hour.
Please help ASAP. A car engine with a mass of 1750 kg can exert 215 000 W. a) How long will it take the car to reach 95.0 km/h if the car is 100% efficient? b) If it actually takes the car 6.5 s to reach 95.0 km/h, what is the efficiency of the car?
✔ First step : calculate the kinetic energy that this car requires to reach 95 km/h
95/ 3,6 ≈ 26,4 m/s
Ec = ½ m x V²
With Ec in J; m in kg; and V in m/s
Ec = ½ 1750 x 26,4² Ec ≈ 610 000 J✔ Knowing that the car has a p power of 215,000 W, so :
T = E/P
T = 610 000/215 000 T ≈ 2.8 s The car takes 2.8 s to reach 95 km/h QUESTION②)N = 2,8/6,5 x 100 = 43.07
The car efficiency is 43 %2. Calcula la presión que se ejerce una bicicleta sobre el suelo. Si la bicicleta tiene un peso de 620kg y el área de la superficie rectangular es de 0.5m x 0.6m.
Responder:
20253.33N / m²Explicación:
La presión se define como la fuerza ejercida por un cuerpo por unidad de área de sección transversal de ese cuerpo.
Presión = Fuerza / Área de sección transversal
Dada la masa de la bicicleta m = 620 kg
Peso de la bicicleta = mg = 620 * 9.8
Peso de la bicicleta = 6076N
Si la dimensión de su área de superficie es 0.5m por 0.6m, el área de la sección transversal será 0.6m * 0.5m = 0.30m²
Presión que ejerce la bicicleta en el suelo = 6076 / 0.30 = 20253.33N / m²
What includes a distance and a direction? A. Acceleration B. Speed C. Displacement D. Velocity
Answer:displacement
Explanation:
A truck is moving with a certain uniform velocity. It is accelerated uniformly by 0.75 m/s^2. After 20 seconds , the velocity becomes 72km/h.Find the initial velocity
Answer:
Vi = 5 m/s
Explanation:
let (a) acceleration = 0.75 m/s²
(t) time = 20 seconds
Vf = final velocity = 72 km/hr (convert to m/s to units consistency = 20 m/s)
find Initial velocity (Vi)
Vf - Vi
a = -----------
t
Vi = Vf - (a * t) = 20 - (0.75 * 20)
Vi = 5 m/s
Round the numbers that follow to three significant figures and express the result in standard exponential notation: (a) 143,700; (b) 0.09750; (c) 890,000; (d) 6,764E4; (e) 33,987.22; (f) - 6.5559.
Explanation:
Non-zero digits are always significant.
Zeros between significant digits are also significant.
Trailing zeros are significant only after a decimal point.
(a) 143,700
First, write in scientific notation.
1.437×10⁵
Now, round to 3 significant figures.
1.44×10⁵
(b) 0.09750
= 9.750×10⁻²
= 9.75×10⁻²
(c) 890,000
= 8.9×10⁵
= 8.90×10⁵
(d) 6,764×10⁴
= 6.764×10⁷
= 6.76×10⁷
(e) 33,987.22
= 3.398722×10⁴
= 3.40×10⁴
(f) -6.5559
= -6.5559×10⁰
= -6.56×10⁰
The scientific notation and round-off of the number are given below:-
(a) 143,700 = 1.44×10⁵
(b) 0.09750 = 9.75×10⁻²
(c) 890,000 = 8.90×10⁵
(d) 6,764×10⁴ = 6.76×10⁷
(e) 33,987.22 = 3.40×10⁴
(f) -6.5559 = -6.56×10⁰
What is a scientific notation?Numbers that are either too large or too little to be conveniently stated in decimal form can be expressed using scientific notation. It may be called scientific form.
When a number is written using only the digits of the number, that is considered standard notation. Since words are not used in conventional number notation, this is the way that numbers are typically written.
Non-zero digits are always significant. Zeros between significant digits are also significant.
Trailing zeros are significant only after a decimal point.
(a) 143,700
First, write in scientific notation.
1.437×10⁵
Now, round to 3 significant figures.
1.44×10⁵
(b) 0.09750
= 9.750×10⁻²
= 9.75×10⁻²
(c) 890,000
= 8.9×10⁵
= 8.90×10⁵
(d) 6,764×10⁴
= 6.764×10⁷
= 6.76×10⁷
(e) 33,987.22
= 3.398722×10⁴
= 3.40×10⁴
(f) -6.5559
= -6.5559×10⁰
= -6.56×10⁰
Therefore, the numbers can be written in the scientific notations as above.
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