Answer:
Friction force always acts tangent to the surface at points of contact. Friction force acts opposite to the direction of motion.
Explanation:
A spherical mirror gives an image magnified 5 times at a distance 5 m. determine whether the mirror is convex or concave? How much will be the focal length of the mirror?
Answer:
1. Concave mirror.
2. 4.17 m or 417 cm.
Explanation:
The following data were obtained from the question:
Object distance (u) = 5 m
Magnification (M) = 5
Focal length (f) =..?
1. Identification of the mirror.
To determine whether or not the mirror is concave or convex, we must first of all calculate the image distance.
This can be obtained as follow:
Object distance (u) = 5 m
Magnification (M) = 5
Image distance (v) =.?
Magnification (M) = image distance (v) /object distance (u).
M = v/u
5 = v/5
Cross multiply
v = 5 x 5
v = 25 m
Since the image distance obtained is positive, the mirror is said to be a concave mirror.
2. Determination of the focal length of the mirro.
This can be obtained as follow:
Object distance (u) = 5 m
Image distance (v) = 25 m
Focal length (f) =...?
1/f = 1/v + 1/u
1/f = 1/25 + 1/5
1/f = 0.04 + 0.2
1/f = 0.24
Cross multiply
f x 0.24 = 1
Divide both side by 0.24
f = 1/0.24
f = 4.17 m
Converting the focal length of cm, we have:
1 m = 100 cm
Therefore, 4.17 m = 4.17 x 100 = 417 cm
Therefore, the focal length of the mirror is 4.17 or 417 cm.
Active 13 minutes ago
6. Thrust exerted by an object of area 20 m experiencing pressure 150 Nm‐² is
a 3000 km
b. 3000 N
c. 2800 Kg
d 2800 N/m
Answer:
3000 N
Explanation:
As we know that
pressure=force/area
force=thrust
so pressure=thrust/area
thrust=pressure*area
pressure=150 Nm^-2
area=20m^2
so thrsut=150*20=3000 N
Research have found that other than for reasons of hunger, American women eat when they are depressed ,whereas Japanese women eat because of social demands.They found no significant differences between american and japanese men. These results demonstrate that ________ and _______ must be taken into account when studying why and under what circumstances people eat.
Answer:
culture
food
Explanation:
The above mentioned studied the interaction between food and culture. Food habits reflect different meanings in different cultures. As per the question, the United States America and Japan are two countries far away from each other, which have distinct cultures and gave rise to different eating norms. However, the impact of media have been shaping the eating patterns around the globe, which have brought different food and cultures together.
4.
An "extreme" pogo stick utilizes a spring whose uncompressed length is 46 cm and whose force constant is 1.4 x 104 N/m. A 60-kg person is jumping on the pogo stick,
compressing the spring to a length of only 5.0 cm at the bottom of their jump. Which is the upward acceleration of the person at the moment the spring reaches its greatest
compression at the bottom of their jump?
6 m 2
Answer:
a = 85.9 m / s²
Explanation:
For this exercise we can use Newton's second law in the most compressed part
F - W = m a
force is the spring elastic force
F = - k Δx
k Δx - m g = m a
a = k/m Δx - g
Δx = x₀ -[tex]x_{f}[/tex]
ΔX = 46 - 5 = 41cm (1m / 100cm) = 0.41 m
let's calculate
a = 1.4 10⁴/60 0.41 - 9.8
a = 85.9 m / s²
When a constant force acts upon an object, the acceleration of the object varies inversely with its mass. When a certain constant force acts upon an object with mass , the acceleration of the object is . If the same force acts upon another object whose mass is , what is this object's acceleration 19 4 2
Answer:
The acceleration of the object is 4 m/s².
Explanation:
When a constant force acts upon an object, the acceleration of the object varies inversely with its mass i.e.
[tex]a=\dfrac{k}{m}[/tex] ...(1)
Let us assume that the question is a certain force acting upon an object with mass 2 kg produces an acceleration of 38 m/s². if the same force acts upon another object whose mass is 19 kg, what would this object's acceleration be
Equation (1) can be written as :
[tex]\dfrac{a_1}{a_2}=\dfrac{m_2}{m_1}[/tex]
Here,
a₁ = 38 m/s², a₂ =?, m₁ = 2 kg, m₂ = 19 kg
So,
[tex]\dfrac{38}{a_2}=\dfrac{19}{2}\\\\a_2=4\ m/s^2[/tex]
So, the acceleration of the object is 4 m/s².
A car drives at a constant speed of 21 m/s around a circle of radius 100 m.
What is the centripetal acceleration of the car?
O A. 4.8 m/s2
O B. 0.21 m/s2
O C. 3.1 m/s2
O D. 4.4 m/s2
Answer:
Option D. 4.4 m/s²
Explanation:
The following data were obtained from the question:
Velocity (v) = 21 m/s
Radius (r) = 100 m
Centripetal acceleration (a) =.?
The centripetal acceleration of the car can be obtained as follow:
Centripetal acceleration (a) = Velocity square (v²) / radius (r)
a = v²/r
a = 21²/100
a = 441/100
a = 4.41 ≈ 4.4 m/s²
Therefore, the centripetal acceleration of the car is 4.4 m/s².
3. Assume that each atom of copper contributes one free electron. The density of Cu is 9g/cc and atomic weight is 63g. if the current flowing through the copper wire of 1mm dia is 1.1A, drift velocity of electrons will be-
Answer:
[tex]v_d=0.1\ mm/s[/tex]
Explanation:
The current flowing through a conductor is given as:
[tex]I=neAv_d\\where\ A =area\ of\ conductor=\pi d^2/4=\pi(1*10^-3)^2/4=7.85*10^{-7}\\\\I=current\ flowing\ through\ the \ conductor=1.1A\\\\e=charge\ of \ electron=1.602*10^{-19}\\\\N_A=Avogadro \ constant=6.023*10^{23}\ mol^{-1}\\\\Density=9*10^3kg/m^3=9*10^6g/m^3\\\\n=\frac{6.023*10^{23}\ mol^{-1}*9*10^6\ g/m^3}{63\ g/mol} =8.604*10^{28}\ m^{3}\\\\v_d=\frac{I}{neA}=\frac{1.1}{8.604*10^{28}*1.602*10^{-19}*7.85*10^{-7}}=0.0001\ m/s\\\\v_d=0.1\ mm/s[/tex]
The angle of incidence of a ray of light striking an equilateral triangular prisms ABC of refracting angle 60o is 40o. Calculate:
(i)the angle of refraction at the first face
(ii)the angle of emergence
Answer:
1: the refracted angle in the first face is equal to the incident angle that is 60degrees
2. Emergence Angle is 42degrees
Explanation:
Pls see attached file
Why does time seem to flow only in one direction?
Answer:
Time seem to flow only in one direction because if it started to go in backward direction that would break the second law of thermodynamics. We do not find time to be moving in any direction because time is not an object that can move nor is it a force that can move any object.
Barry walks from one end to the other of a 30-meter long moving walkway at a constant rate in 30 seconds, assisted by the walkway. When he reaches the end, he reverses direction and continue walking with the same speed, but this time it takes him 120 seconds because he is traveling against the direction of the moving walkway. If the walkway were to stop moving, how many seconds would it take Barry to walk from one end of the walkway to the other
Answer:
Δt=48 s
Explanation:
v: Barry's speed
v.: speed of the walkway
Δx=30 m
Δt1=30 s , Δt2=120 s
|Δx1|=|Δx2|
Δx=v*Δt
=> (v+v.)*30=(v-v.)*120
v=v.*5/3
30=(v+v.)*30
=> 30=(5v./3 +v.)*30
v.=3/8 m/s
v=5v./3 , v.=3/8
=> v=5/8 m/s
Δx=v*Δt
30=5/8 *Δt
Δt=48 s
Which statement describes how work and power are similar?
A: You must know time and energy to calculate both.
B: You must know velocity and time to calculate both.
C: You must know force and distance to calculate both.
D: You must know energy and force to calculate both.
Answer:
C: You must know force and distance to calculate both.
Explanation:
A force is said to have done work, when it has succeeded in causing displacement in an object from its starting point.
Power can be defined as the rate of doing work.
The work can be calculated using the following formula:
Work done = Force × Displacement
The power can be calculated using the following formula:
Power = Work \ Time
In order to calculate the work and power, the force and distance should be known. The force and distance will help in the calculating the work, which will in turn help in the calculation of the power of the object.
Hence, the answer is you must know force and distance to calculate both.
Theere is more role of the moon than sun to occur tides in oceans why?
Help
Answer:
Because ocean tides are the effect of ocean water responding to a gravitational gradient, the moon plays a larger role in creating tides than does the sun. But the sun's gravitational gradient across the earth is significant and it does contribute to tides as well.
i hope this help i
i try to explain and like i sayed i hope this help u.
Answer:
the moon
Explanation:
ive passed the grade you learned this in
What is the acceleration of a cabinet of mass 45 kilograms if Jake and Ted push it by applying horizontal force of 25 newtons and 18 newtons respectively in the same direction
Answer:
[tex]a=0.96\ m/s^2[/tex]
Explanation:
Given that,
Mass of cabinet, m = 45 kg
Two horizontal force of 25 newtons and 18 newtons respectively in the same direction.
When the forces are acting in same direction, the net force is equal to the sum of forces i.e.
F = 25 N + 18 N = 43 N
Let a is the aceleration of the cabinet
So,
F = ma
[tex]a=\dfrac{F}{m}\\\\a=\dfrac{43}{45}\\\\a=0.96\ m/s^2[/tex]
So, the acceleration of the cabinet is [tex]0.96\ m/s^2[/tex].
Magnetic field lines form closed loops:________.
a) Around and through bar magnets.
b) Through current-carrying loops.
c) Around current-carrying straight wires.
d) All of the above.
Answer:
d) All of the above.
Explanation:
Magnetic field lines are formed around an object when there is a magnetic field around the object. From the question, we know that a bar magnet has an electric field. A current carrying loop has a magnetic field around it also. Current carrying straight wires and any conductor generally, carrying an electric current, produces a magnetic field around them. This magnetic field has lines of loos formed close to the material.
To get an idea how big a farad is, suppose you want to make a 1.0-F air-filled parallel-plate capacitor for a circuit you are building. To make it a reasonable size, suppose you limit the plate area to 1.4 cm2 .
Part A
What would the gap have to be between the plates?
Express your answer using two significant figures and include the appropriate units.
Part B
Is this practically achievable?
Is this practically achievable?
a. yes
b. no
Answer:
The gap between the plates will be 1.2 x 10^-15 m
No, this is not practically achievable.
Explanation:
Capacitance = 1.0 F
area of plate = 1.4 cm^2 = 1.4/10000 m^2 = m^2
distance = ?
We use the equation
[tex]C[/tex] = [tex]\frac{A}{d}[/tex]*ε
C is the capacitance
where A is the area
d is the distance of separation of plates
ε is the permeability of free space = 8.854×10^-12 F⋅m−1
substituting values, we have
1 = [tex]\frac{0.00014}{d}[/tex]* 8.854×10^-12
distance between plates = 1.2 x 10^-15 m
This is not practically achievable in real life
WILL MARK AS BRAINLIEST...,.. A constant force vector f =2i cap+3j cap-5k cap acts on a particle and displaces it from (1,2,-3) m to (2,5,-1) m. find the work done by the force .
Explanation:
Given that,
Force, [tex]F=2i+3j-5k[/tex]
The particle displaces from (1,2,-3) m to (2,5,-1) m.
We need to find the work done by the force. Work done by the force is given by :
W = Fd
It is equal to the dot product of force and displacement.
Displacement from (1,2,-3) m to (2,5,-1) m is (2-1, 5-2, -1-(-3)) or (1, 3, 2) m
Work done,
[tex]W=F{\cdot} d\\\\W=(2i+3j-5k){\cdot} (i+3j+2k)[/tex]
We know that, i.i=j.j=k.k=1
So,
[tex]W=1\ J[/tex]
So, the work done by the force is 1 J.
Velocity is a description of an object’s blank
Velocity is the description of an object's motion from one point to another.
It tells the speed with which the trip is completed, and the direction from the start-point to the end-point. It tells nothing about any twists, turns, loops, bends, or stops along the way.
please help me with this
Answer:
12 Ω
Explanation:
Data obtained from the question include:
Resistor 1 (R1) = 50 Ω.
Resistor 2 (R1) = 30 Ω.
Resistor 3 (R3) = 20 Ω.
Resistor 4 (R4) = R
Galvanometer reading = Zero deflection.
The Resistor 4 (R4) in the Wheatstone bridge can be obtained as follow:
Since the galvanometer gives zero deflection, it means the bridge is balanced. Therefore,
R1/R2 = R3/R4
50/30 = 20/R
Cross multiply
50 x R = 30 x 20
Divide both side by 50
R = (30 x 20)/50
R = 12 Ω
Therefore, the value of R in the wheatstone bridge is 12 Ω.
An angular frequency wave ω0 has an average power P0. If your angular frequency increases by 20%, find the percentage by which its power increases.
Answer:
44%
Explanation:
The average power of a wave is directly proportional to the square of the frequency.
P ∝ ω²
Writing a proportion:
P₁ / P₀ = ω₁² / ω₀²
P₁ / P₀ = (1.2 ω₀)² / ω₀²
P₁ / P₀ = 1.44
P₁ = 1.44 P₀
The power increases by 44%.
If the absolute pressure inside the bottom of a container open to the atmosphere and filled with an unknown substance is 300 Pa. And the height of the container is 800.0 cm. What is the density of the substance?
Answer:
2.5 kg/m³
Explanation:
Absolute pressure = gauge pressure + atmospheric pressure
P = Pg + Pa
The gauge pressure caused by the weight of a fluid is called the static pressure. It is equal to the density of the fluid × acceleration due to gravity × depth of the fluid,
Pg = ρgh
Therefore:
P = ρgh + Pa
300 Pa = ρ (10 m/s²) (8.00 m) + 100 Pa
ρ = 2.5 kg/m³
Determine whether or not each of the following statements is true. If a statement is true, prove it. If a statement is false, provide a counterexample and explain how it constitutes a counter-example.
A capacitor consists of two flat, metal plates with unequal areas. Each of the plates starts neutral, and then each plate is connected to a dierent terminal of a battery. After some time, the plates will have excess charge on them, and the magnitude of the excess charge on one plate will equal the magnitude of the excess charge on the other plate.
A. True
B. False
If a wire carries current, then it has a net non-zero charge in it.
A. True
B. False
Answer:
a) True b) True
Explanation:
a) a capacitor is made up of two flat plates and each one has a charge of the same sign, therefore the statement is true
b) the current is the flow of electrons per unit of time, therefore the charge is not zero, therefore the statement is True
what is the formula for velovity?
Answer:
if it's velocity u talking of.....
Explanation:
then it's displacement/ time
The water tank is kept at some height of the buildings. Why?
Answer:
The water is at the top because when the water is stored at the top it does not need as much energy to get it to flow because it will be flowing down and be affected by gravity to make the water pressure.
Answer:
The water is at the top because when the water is stored at the top it does not need as much energy to get it to flow because it will be flowing down and be affected by gravity to make the water pressure.
Explanation:
What does Electromagnetic induction mean?
Transformers are of two types: Step up and Step down.
What is step up transformer?
What is step down transformer?
What is the difference between them?
Please I really need help.
Don't answer the question for points if you don't know what it means!
Answer:
Electromagnetic introduction is the production of an electromotive force (voltage) across an electrical conductor in a changing magnetic field.
Step up transformers is a transformer in which the output (secondary) voltage is greater than its input (primary) voltage is called a step-up transformer. The step-up transformer decreases the output current for keeping the input and output power of the system equal.
Step down transformer is a transformer in which the output (secondary) voltage is less than its input (primary) voltage is called a step-down transformer. The number of turns on the primary of the transformer is greater than the turn on the secondary of the transformer.
The difference between them:
A transformer is a static device which transfers a.c electrical power from one circuit to the other at the same frequency, but the voltage level is usually changed. For economical reasons, electric power is required to be transmitted at high voltage whereas it has to be utilized at low voltage from a safety point of view. This increase in voltage for transmission and decrease in voltage for utilization can only be achieved by using a step-up and step-down transformer.
Hopefully this helped.
HELP!?
Convert 107 km/h into m/s.
Answer: 29.72
Explanation:
you multiply the number by 5 then divide by 18=
107x5= 535
535/18= 29.72
A wire carrying a 35.0 A current passes between the poles of a strong magnet such that the wire is perpendicular to the magnet's field, and there is a 2.55 N force on the 3.00 cm of wire in the field. What is the average field strength (in T) between the poles of the magnet
Answer:
7.65 T
Explanation:
From the question,
Using,
F = BILsinФ......................... Equation 1
Where F = Force, B = magnetic field strength, I = current, L = Length, Ф = Angle.
Make B the subject of the equation
B = F/ILsinФ........................Equation 2
Given: F = 2.55 N, I = 32 A, L = 3.00 cm = 0.03 m, Ф = 90° (perpendicular)
Substitute into equation 2
B = 2.55/(32×0.03×sin90°)
B = 2.55/0.96
B = 7.65 T
a bicycle has a momenum of 36kg•m/s and a velocity of 4m/s. what is the mass of the bicycle?
A cheetah can start from rest and attain the velocity 72km/h in 2 seconds. Calculate the acceleration of cheetah.
Answer:
Acceleration(a)=21.60 km/h or 21,600 m/s
Explanation:
Since you have the initial velocity(0, because it starts from rest) and the final velocity 72 km/h or 72,000 m/s. so...
[tex]a=\frac{Vf-Vi}{t}\\ a=\frac{72,000 m/s-0}{2s}\\ a=\frac{72,000 m/s}{2s}\\ a=36,000m/s or 36 km/h[/tex]
What force is required to give an object with mass 300 kg an acceleration of 2
m/s2?
O A. 300 N
O B. 1200 N
O C. 600 N
O D. 150 N
Answer:
C. 600 N
Explanation:
Given,
mass of object (m)= 300kg
acceleration(a) =2m/s^2
We know that,
Force(F)=ma
=300*2
=600N
So,600N force is required to give an object.
Answer:
600 N
Explanation:
aye pecks
in , the balls are quite small and come in a variety of
, ranging from extra- super slow to fast
Answer:
in squash, the balls are quite small and come in a variety of
speeds, ranging from extra- super slow to fast
Explanation: