A magnetic compass is placed near an insulated copper wire. When the wire is connected to a battery and a current is created, the compass needle moves and changes its position. Which is the best explanation for the production of a force that causes the needle to move?
Explanation:
When the wire is connected to a battery, the compass needle moves and changes its position. This happens because the needle magnetizes the copper wire, thus, creating a force.
While the current in the wire produces a magnetic field and exerts a force on the needle. The insulation on the wire becomes energized and exerts a force on the needle. Hence, the compass needle moves and changes its position.
A uniform plank 4 m long is pivoted about its center to an angle of 30° with the vertical. What magnitude of force
must be applied 0.5 m from the pivot to maintain equilibrium with a 4 kg mass hanging from one end?
A. 80 N
B. 20 N
C. 40 N
D. 60 N
E. 100 N
Answer:
A. 80 N
Explanation:
Since the uniform plank is pivoted at its center at an angle of 30 to the vertical, then it is 90° - 30° = 60° to the horizontal.
Let L be the length of the plank = 4 m, the perpendicular distance of the 4 kg mass form the pivot point is Lcos60°/2. Then the moment of the 4 kg mass about its pivot point is mgLcos60/2 where m = mass = 4 kg and g = acceleration due to gravity = 10 m/s²
Let F be the force applied at 0.5 m from the pivot point. The perpendicular distance of F from the pivot point is 0.5cos60°. Thus the moment of this force about the pivot point is F × 0.5cos60° = 0.5Fcos60°
Since both moments are the same for equilibrium,
mgLcos60/2 = 0.5Fcos60°
F = mgL/(2 × 0.5 m)
F = 4 kg × 10 m/s² × 4 m/1 m
F = 80 kgm/s²
F = 80 N
1. I get so much energy when I eat candy! What type of energy is this statement referring to?
O mechanical
O kinetic
O potential
O chemical
The answer is chemical
A blow-dryer and a vacuum cleaner each operate with a voltage of 120 V. The current rating of the blow-dryer is 14 A, while that of the vacuum cleaner is 4.2 A. Determine the power consumed by (a) the blow-dryer and (b) the vacuum cleaner. (c) Determine the ratio of the energy used by the blow-dryer in 16 minutes to the energy used by the vacuum cleaner in 43 minutes.
Answer:
The correct solution is:
(a) 1680 W
(b) 504 W
(c) 1.240
Explanation:
The given values are:
Voltage,
V = 120 V
Current of blow dryer,
I₁ = 14 A
Current of vacuum cleaner,
I₂ = 4.2 A
Time,
t₁ = 16 min
t₂ = 43 min
As we know,
⇒ [tex]Power (P) = VI[/tex]
(a)
For blow dryer:
⇒ [tex]P_1=V\times I_1[/tex]
[tex]=120\times 14[/tex]
[tex]=1680 \ W[/tex]
(b)
For Vacuum cleaner:
⇒ [tex]P_2=V\times I_2[/tex]
[tex]=120\times 4.2[/tex]
[tex]=504 \ W[/tex]
(c)
The ratio will be:
= [tex]\frac{Blow \ dryer \ energy}{Vacuum \ cleaner \ energy}[/tex]
= [tex]\frac{P_1\times t_1}{P_1\times t_2}[/tex]
= [tex]\frac{1680\times 16}{504\times 43}[/tex]
= [tex]\frac{26880}{21672}[/tex]
= [tex]1.240[/tex]
Iron meteorites are interpreted as deriving from the cooled metallic core of a largeish asteroid. This is based upon:
Answer:
This is based upon the fact that meteorites are generally believed to have originated as solid debris from Larger bodies like meteoroid or asteroids
Explanation:
Iron meteorites are interpreted as deriving from the cooled metallic core of a larger asteroid , because meteorites are generally believed to have originated as solid debris from Larger bodies like meteoroid or asteroids that are located outside the planet but found their way into our planet .
how much energy must be absorbed by 20.0 g of water to change its temperature from 95 degrees celsius to 125 degrees celsius
Answer:
I got 2508 J
Explanation:
q=mct
125-95
= 30 * 4.18 * 20
= 2508
The firing of a bullet by a rifle causes the rifle to recoil backwards. The speed of
the rifle's recoil is smaller than the bullet's forward speed because the___
A.)force against the rifle is relatively small
B.)speed is mainly concentrated in the bullet
C.)rifle has lots of mass
D.)momentum of the rifle is unchanged
Answer:c i.e. rifle has lots of mass
Explanation:It's because we know that the force of recoiling is same. But since the mass of rifle is very much greater than that of the bullet, it's balanced by the less speed of the recoiling of the rifle.
the answer is b :)
Samples of different materials, A and B, have the same mass, but the sample
of A is higher in density. Which statement could explain why this is so?
A. The particles that make up material B are more closely packed
together than the particles that make up material A.
B. The particles that make up material A have more mass than the
particles that make up material B.
C. The sample of material A has greater volume than the sample of
material B.
D. The particles that make up material B have more mass than the
particles that make up material A.
Answer:
Answer is letter B
Answer: THE CORRECT ANSWER IS : The partiles that make up material B are more closely packed together than the partiles that make up material A
Explanation: I TOOK THE TEST apex
The series circuit depicts three resistors connected to a voltage
source. The voltage source (AVtot) is a 110-V source and the resistor
values are 7.2 (R1), 6.2 A2 (R2) and 8.6 22 (R3).
b. Determine the current in the circuit.
A
c. Determine the voltage drops across each individual resistor.
Answer:
B. Current in the circuit is 5.
Ci. Voltage across 7.2 Ω (R₁) is 36 V
Cii. Voltage across 6.2 Ω (R₂) is 31 V
Ciii. Voltage across 8.6 Ω (R₃) is 43 V
Explanation:
We'll begin by calculating the number equivalent resistance in the circuit. This can be obtained as follow:
Resistor 1 (R₁) = 7.2 Ω
Resistor 2 (R₂) = 6.2 Ω
Resistor 3 (R₃) = 8.6 Ω
Equivalent Resistance (R) =?
Since the resistors are in series connection, the equivalent resistance can be obtained as follow:
R = R₁ + R₂ + R₃
R = 7.2 + 6.2 + 8.6
R = 22 Ω
B. Determination of the current.
Voltage (V) = 110 V
Resistance (R) = 22 Ω
Current (I) =?
V = IR
110 = I × 22
Divide both side by 22
I = 110 / 22
I = 5 A
Therefore, the current in the circuit is 5.
Ci. Determination of the voltage across 7.2 Ω (R₁)
Resistor 1 (R₁) = 7.2 Ω
Current (I) = 5 A
Voltage 1 (V₁) =?
V₁ = IR₁
V₁ = 5 × 7.2
V₁ = 36 V
Therefore, the voltage across 7.2 Ω (R₁) is 36 V
Bii. Determination of the voltage across 6.2 Ω (R₂)
Resistor 2 (R₂) = 6.2 Ω
Current (I) = 5 A
Voltage 2 (V₂) =?
V₂ = IR₂
V₂ = 5 × 6.2
V₂ = 31 V
Therefore, the voltage across 6.2 Ω (R₂) is 31 V
Ciii. Determination of the voltage across 8.6 Ω (R₃)
Resistor 3 (R₃) = 8.6 Ω
Current (I) = 5 A
Voltage 3 (V₃) =?
V₃ = IR₃
V₃ = 5 × 8.6
V₃ = 31 V
Therefore, the voltage across 8.6 Ω (R₃) is 43 V
A 9 kg box is placed on a 6 m tall shelf. What will be the kinetic energy of the box right before it hits the ground? (use g = 10 m/s/s)
Answer:
540 J
Explanation:
U at top equals to K at bottom if it's an isolated system therefore U at top is equals to 540 J so we can assume that at 0m U=0 (mgh) therefore the box has gained some velocity due to the acceleration due to g and we can calculate it using 1/2mv²
Juan's mother drives 12.5 miles southwest to her favorite shopping mall. What is the velocity of her
automobile if she arrives at the mall in 7.25 minutes?
Answer:
v1= 12.5miles, t= -7.25m, a= 0
v= 1/2at^2
v= 1/2×
Ron weighs a bottle with a mass of 0.5 kilograms on a spring scale. The spring stretches by 1 centimeter. He then weighs a second bottle on the same spring scale. What is the mass of the second bottle, in kg, if the spring stretches by 2 cm
Answer:
1 kg
Explanation:
Applying,
Hook's law,
F = ke................. Equation 1
Where F = force, k = force constant of the spring, e = extension.
But from the question,
The weight of the bottle is the force acting on the spring scale
therefore,
mg = ke............ Equation 2
Where m = mass of the bottle, g = acceleration due to gravity.
make k the subject of the equation
k = mg/e............ Equation 3
Given: m = 0.5 kg, e = 1 cm = 0.01 m
Constant: g = 9.8 m/s²
k = (0.5×9.8)/0.01
k = 490 N/m
If the mass of the second bottle is weighed,
given: e = 2 cm = 0.02 m
subtitute into equation 1
m×9.8 = 490×0.02
9.8m = 9.8
m = 9.8/9.8
m = 1 kg.
Hence the mass of the second bottle is 1 kg
For general projectile motion with no air resistance, the vertical component of a projectile's acceleration For general projectile motion with no air resistance, the vertical component of a projectile's acceleration remains a non-zero constant. continuously decreases. first decreases and then increases. is always zero. continuously increases.
Answer:
Rmains constant
Explanation:
The equation of the trajectory of a projectile motion is presented as follows;
[tex]Y = x \cdot tan \theta -\dfrac{g \cdot x^2}{2 \cdot u^2 \cdot cos^2 \theta}[/tex]
The vertical componet of the prjectile motion is
y = (u·sinθ)·t - g·t²/2
Where;
θ = The angle with which the projectile is launched
x = The horizontal distance
u = The initial velocity of the projectile
g = The acceleration due to gravity = Constant
t = The time of motion
The acceleration acting on the projectile is the 'g' which is the constant acceleration due to gravity
Therefore, for general projectile motion with no air resistance, the vertical component of the projectile acceleration remains constant
a toy car takes .60 seconds to travel .30 meters after it is released from rest. what is the acceleration of the toy car?
The equivalent resistance of a complex circuit is usually determined by a dividing the sum of the individual resistances by the number of resistances. b adding and subtracting individual resistances. c inspection. d simplifying the circuit into groups of series and parallel circuits.
Answer:
d
Explanation:
we simplify the circuit into groups to obtain a complete circuit I.e series and parallel circuit
Reason whether or not work is done in the following cases:
A. a basketball player shoots a free throw.
B. a peasant pulls a rope tied to a donkey without being able to displace it from its position.
Answer:
A work is done because the object moved
B no work is done because the donkey didnt move
Explanation:
A charge Q creates an electric field. At a distance of 10 cm, the electric field strength
is 30 N/C. What is the electric field strength at a distance of 20 cm? NO LINKS.
1) 7.5 N/C
2) 15 N/C
3) 60 N/C
4) 120 N/C
Answer:
simltinoues divide two eqn El÷E2 Kq\ r^2\kq \2r^2 then you get it 7.5 N\c the answer is A
Which is the preserved evidence of the activity of an organism?
Answer:
Fossils are the remains of an ancient organism or the traces of activity of such an organism. There are two types of fossils: body fossils and trace fossils. Body fossils include preserved remains of an organism (i.e. freezing, drying, petrification, permineralization, bacteria and algea).
I WILL MARK YOU THE BRAINLIEST LINKS WILL BE REPORTED
put the correct words with the correct pictures
A beam of light hits a mirror at an angel of 35 degrees. What is the angel that it bounces off at?
a. 55 degrees
b. 35 degrees
c. 90 degrees
Answer:
c
Explanation:
light refraction is a right angle
A car initially at rest undergoes uniform acceleration for 6.32 seconds and covers a distance of 120 meters. What is the approximate acceleration of the car?
Answer:
Explanation:
The equation for acceleration is
[tex]a=\frac{v_f-v_0}{t}[/tex]. We have the initial velocity since we are told that the car started from rest. What we don't have is the final velocity. But we can find it because we were told that the car undergoes uniform acceleration, so the equation
d = rt will give us that final velocity.
120 = r(6.32) so the velocity or rate of the car is
r = 19 m/s. Plug that in to find the acceleration of the car:
[tex]a=\frac{19-0}{6.32}[/tex] so
a = 3.0 m/s/s
What is the normal force and gravitational force on a 55 kg person standing stationary?
Answer:
539.55 N for both
Explanation:
F=ma
Mass is given at 55kg
And when finding gravitational force gravity's constant is an acceleration of 9.81m/s
F=(55)(9.81)
F= 539.55 N (for both)
Normal force cancels out gravitational force that's why we don't fall throught the floor.
We push down on the floor due to gravitational force but normal force keeps us upright pushing an equal amount back.
which one of the following is not a derived quantity a)speed b)velocity c)time d)force
Answer:
c) time
Explanation:
time is a fundamental quantity from which other quantities are derived
why we need system of measurement
Answer:
Without the ability to measure, it would be difficult for scientists to conduct experiments or form theories. Not only is measurement important in science and the chemical industry, it is also essential in farming, engineering, construction, manufacturing, commerce, and numerous other occupations and activities.
Explanation:
A beaker containing water at 80°C is placed on a piece of aluminum at 25°C. How will thermal energy transfer? O by conduction from the aluminum to the beaker O by convection from the aluminum to the beaker O by convection from the beaker to the aluminum O by conduction from the beaker to the aluminum
The thermal energy transfer will occur by convection from the aluminium to the beaker.
Thermal energy can be defined as the energy held in a system that is accountable for the overall temperature of the system.
Conduction is the process by which heat energy is transferred from one material or substance to another.
Convection is the transfer of heat in the fluid medium. e.g when a fluid is heated, heat energy is transferred into the fluid which causes a rise in the temperature of the fluid.
Since water is a fluid medium, the thermal energy transfer will occur by convection from the aluminium to the beaker.
Learn more about thermal energy here:
https://brainly.com/question/7541718
write the application of gravitational force
Answer:
Applications of Gravitational Force:
Gravity keeps your feet on the ground. Gravity holds the air down. Gravity makes the Earth roughly spherical. Gravity keeps the Moon (and all those artificial satellites) orbiting around the Earth. Gravity keeps the Earth orbiting around the Sun and the Sun orbiting around the galactic centre. Gravity creates the water pressure that runs hydroelectric turbines at the bottom of dams. Gravity brings the rain back down after it evaporates into the atmosphere.20 POINTS:
Why does the initial hill of a roller coaster need to be steep?
Answer: A roller coaster does not have an engine to generate energy. The climb up the first hill is accomplished by a lift or cable that pulls the train up. This builds up a supply of potential energy that will be used to go down the hill as the train is pulled by gravity
Hope this helps! Good luck with future homework and exams!
Which of the following has the most kinetic energy?
A. A 25-kg fish tank sitting on a table
B. A 50-g fish swimming in a fish tank
C. A 7,500-kg car parked on a steep hill
D. A 50-kg Boulder suspended from a cliff
Answer:
The answer is B
Explanation:
Only things that are moving have kinetic energy, therefore B is the only correct answer
How much energy is required to move an electron through a potential difference of
12 V?
1) 1.9 x 10^- 18 )
2) 7.5 x 10^- 18 )
3) 1.3 x 10^-20)
4) 7.5 x 10^18 J
The ship was travelling 93 meters per second, 25 degrees above the x-axis Northeast. Determine the magnitude and direction of the horizontal vector component, Vx.
Answer: [tex]92.18\ m/s[/tex], east
Explanation:
Given
Ship is traveling at a speed of [tex]v=93\ m/s[/tex]
Direction of ship is [tex]25^{\circ}[/tex] North of east
If we break velocity vector in x and y axes then, the horizontal component is given by
[tex]\Rightarrow v_x=93\cos 25^{\circ}\\\Rightarrow v_x=92.18\ m/s[/tex]
The direction of horizontal component is towards east with magnitude of [tex]92.18\ m/s[/tex]