Find the velocity of a dolphin that swims 55 m in 5.0 s.
Answer: 11 m/s
Explanation: velocity = distance /time = 55 m /5.0 s
Answer:40km/h
Explanation:
How much work is done by 15 kW engine during 3.5 min? Explain the answer if you can plz
Answer:
W = 3.15 · 10⁶ J
Explanation:
We know that power is calculated using the formula:
P = W/twhere P = power (W), W = work (J), and t = time (s)We can derive a formula for work using this formula by multiplying t to both sides of the equation.
W = PtLet's convert 15 kW to W.
15 kW → 15,000 WLet's convert 3.5 min to s.
3.5 min → 210 sSubstitute these values into the formula for work and solve for W.
W = Pt W = (15,000 W) · (210 s) W = 3,150,000 J W = 3.15 · 10⁶ JThis is the amount of work done by a 15 kW engine in 3.5 minutes.
who compose the Ghana national anthem
Answer:
Philip Gbeho
Explanation:
The human body stores chemical energy from digested food. Some of the chemical energy is converted into mechanical energy when the body moves. Which statement is best supported by this information?
The body does not convert chemical energy to thermal energy.
The body does not convert chemical energy to kinetic energy.
Digested food is a source of potential energy.
Digested food is a form of radiant energy.
Answer:
Your answer is c :)
Explanation:
The amount of sliding friction depends on the
a. weight of the moving object and the type of surface that the
object slides across.
b. density and volume of the object.
c. acceleration and mass of the object.
d. density and mass of the object.
*help please
Answer:
c I think so do u know the formula for friction??friction? lkke kinetic friction
Which of the following is a conductor?
copper
water
aluminum
all of the above
Answer:
D all of the above
Explanation:
electricity moves easily through all of them and none of them prevent the flow of electricity
What is Na2SO4?
Help pleaseeee.
Please help
The period of an oscillation is measured to be 0.0833 seconds. What is
the frequency of this oscillation? *
1.0833 Hz
0.287 Hz
9.8 Hz
12 Hz
0.007 Hz
Answer:
your
answer is
12.004
1. Only about
% of water on Earth is fresh water that is readily available for human consumption.
a. less than 1
b. 5
c. more than 50
d. All water on Earth is fresh water and is easily accessible.
Answer:
Hey mate.....
Explanation:
This is ur answer....
a. Less than 1%3% of the earth's water is fresh. 2.5% of the earth's fresh water is unavailable: locked up in glaciers, polar ice caps, atmosphere, and soil; highly polluted; or lies too far under the earth's surface to be extracted at an affordable cost. 0.5% of the earth's water is available fresh water....
Hope it helps you,
Mark me brainliest plz....
Follow me! :D
Question:
1. Only about % of water on Earth is fresh water that is readily available for human consumption.
a. less than 1
b. 5
c. more than 50
d. All water on Earth is fresh water and is easily accessible
Answer:
a. less than 1
how much force is needed to accelerate a 2500kg car at a rate of 4m/s2
Answer:
10,000 N
Explanation:
Using Newton's Second Law of Motion, Force = Mass*Acceleration.
Plugin 2500 kg for the mass and 4 m/s^2 for the acceleration.
Force = 2500 kg*4 m/s^2 = 10000 Newtons
(SI unit of force is Newtons)
1. Why is the flow of electrons from A to B?
2. What's the difference between flow of current & flow of electrons and why ar they opposite?
1. because A is more negative than B. A is -1000 V (we can imagine that A has excess 1000 electrons), in other, B which +3000 V can be assume that B need 3000 elctrons to be neutral. So, the electron will flow from A to B.
2. Electrons being negatively charged flow from the negative terminal to the positive terminal of the voltage source. So, the actual direction of current should be from negative to positive terminal. However, the conventional direction had already been established. So, the current flow is considered in the direction opposite to the direction of flow of electrons. (from topperlearning dot com)
What happens when you move two
objects far apart from each other?
A. The force of gravity increases.
B. The force of gravity decreases.
C. Distance does not affect the force of gravity.
D. The friction between the two objects will increase.
Answer:
b
Explanation:
A human body consists of
Answer:
60% of the human adult body is water. According to H.H. Mitchell, Journal of Biological Chemistry 158, the brain and heart are composed of 73% water, and the lungs are about 83% water. The skin contains 64% water, muscles and kidneys are 79%, and even the bones are watery: 31%.
Explanation:
A cylindrical tank with radius 3 m is being filled with water at a rate of 2 m3/min. How fast is the height of the water increasing (in m/min)
Answer:
.0707 m / min
Explanation:
The computation is shown below:
= Flow of the volume ÷ crossectional area
A = π × r^2
= 9 π
= 28.27 m^2
so, the fast of the height of the water rise is
=(2 m^3 / min) ÷ 28.27 m^2
= .0707 m / min
After landing on an unexplored Klingon planet, Spock tests for the direction of the magnetic field by firing a beam of electrons in various directions and by recording the following observations:1. Electrons moving upward feel a magnetic force in the northwest direction.2. Electrons moving horizontally toward the north are pushed downward.3. Electrons moving horizontally toward the southeast are pushed upward.Mr. Spock therefore concludes that the magnetic field at this landing site is in which direction?A) toward the eastB) toward the northeastC) toward the southwestD) toward the southeastE) toward the west
Answer:
the correct one is C,
Explanation:
The magnetic force is given by the expression
F = q v x B
where the bold letters indicate vectors, we can find the modulus of this expression
F = q v B sin θ
The direction of the to the force with the rule of the right hand. The thumb applies in the direction of the speed, the fingers extended in the direction of the magnetic field and if the charge is positive the palm is in the direction of the force, if the charge is megative the force is in the opposite direction to the palm of hand.
Let's analyze the different situations presented; As the particles emitted are electrons, their charge is negative.
Situation 1. The thumb points upwards, the force is towards the NW as the charge is negative, the palm points towards the SE therefore the finger points towards the SOUTHWEST which must be the direction of the magnetic field
Situation 2. the electrons go horizontally to the north the thumb points in this direction, the force is downwards, therefore the palm points upwards, the extended fingers point to the WEST
Situation 3. the thumb points to the SE towards where the electrons move, the force is upwards the palm points to the SW, therefore the fingers extended points SOUTHWEST
As a result of situations 1 and 3 the magnetic field must point in the SOUTHWEST direction.
Situation 2 gives a different result because the component of the field that is directed to the south does not create exerts and therefore cannot be detected.
When checking the answers, the correct one is C
An elevator motor in a high-rise building can do 3500 kJ of work in 5 min. Find the power developed by the motor. Explain if you can plz
Answer:
P = 11666.6 W
Explanation:
Given that,
Work done by the motor, W = 3500 kJ
Time, t = 5 min = 300 s
We need to find the power developed by the motor. Power developed is given by :
[tex]P=\dfrac{E}{t}\\\\P=\dfrac{3500\times 10^3}{300}\\\\P=11666.7\ W[/tex]
So, the required power is 11666.6 W.
Air plane travels 224 in 2 hours.
How fast was the plane traveling?
Answer:
112mph
Explanation:bugyg
A uniform 140 g rod with length 57 cm rotates in a horizontal plane about a fixed, vertical, frictionless pin through its center. Two small 30 g beads are mounted on the rod such that they are able to slide without friction along its length. Initially the beads are held by catches at positions 11 cm on each sides of the center, at which time the system rotates at an angular speed of 23 rad/s. Suddenly, the catches are released and the small beads slide outward along the rod. Find the angular speed of the system at the instant the beads reach the ends of the rod. Answer in units of rad/s.
Answer:
The correct answer is "12 rad/s"
Explanation:
The given values are,
Mass of rod,
M = 140 g
i.e.,
= 0.14 kg
Length,
L = 57 cm
i.e.,
= 0.57 m
Mass of beads,
M = 30 g
i.e.,
= 0.03 kg
Angular speed,
r = 11 cm
i.e.,
= 0.11 m
Now,
The inertia of rods will be:
= [tex]\frac{1}{12}ML ^2[/tex]
On substituting the values, we get
= [tex]\frac{1}{12}\times 0.14\times (0.57)^2[/tex]
= [tex]0.0037905 \ kg-m^2[/tex]
The inertia of beads will be:
= [tex]mr^2[/tex]
On substituting the values, we get
= [tex]0.03\times (0.11)^2[/tex]
= [tex]0.000726 \ kg-m^2[/tex]
The total inertia will be:
= [tex]Inertia \ of \ rods+Inertia \ of \ beads[/tex]
= [tex]0.0037905 + 0.000726[/tex]
= [tex]0.0045165 \ kg-m^2[/tex]
now,
The angular speed of the system will be:
⇒ [tex]L_1w_1=L_2w_2[/tex]
On substituting the values in the above equation, we get
⇒ [tex]0.0045165\times 23 = (0.0037905 + (0.03\times 0.285^2)\times 2 )\times w_2[/tex]
⇒ [tex]0.1038795 = 0.0037905 + (0.00243675\times 2 )\times w_2[/tex]
⇒ [tex]w_2 = 12 \ rad/s[/tex]
A cart moves with negligible friction or air resistance along a roller coaster track. The cart starts from rest at the top of a hill of unknown height. It then goes down that first hill and up another circularly shaped hill of height 10 meters and radius 15 meters. The ride is designed so that the cart just barely loses contact with the track at the top of the second hill (10 meters above ground level). What is the height of the starting hill relative to ground
Answer:
hinit = 17.5 m
Explanation:
Assuming no friction present, the mechanical energy must be conserved, which means that at any point of the trajectory, the sum of the gravitational potential energy and the kinetic energy must keep the same.At the top of the hill, since it starts from rest, all the energy must be potential, and we can express it as follows:[tex]E_{o} = U_{o} = m*g*h_{init} (1)[/tex]
When the car arrives to the top of the second hill, as we know that it is lower than the first one, the energy of the car, must be part gravitational potential energy, and part kinetic energy.We can express this final energy as follows:[tex]E_{f} = U_{f} + K_{f} = m*g* h_{2} + \frac{1}{2} *m*v_{f} ^{2} (2)[/tex]
In order to find hinit, we need to make (1) equal to (2), and solve for it.In (2) we have the value of h₂ (10 m), but we still need the value of the speed at the top of the second hill, vf.Now, when the car is at the top of the hill, there are two forces acting on it, in opposite directions: the normal force (upward) and the weight (downward).We know also that there is a force that keeps the car along the circular track, which is the centripetal force.This force is just the net downward force acting on the car (it's vertical at the top), and is just the difference between the weight and the normal force.If the cart just barely loses contact with the track at the top of the second hill, this means that at that point the normal force becomes zero.So, the centripetal force must be equal to the weight.The centripetal force can be expressed as follows:[tex]F_{c} = m*\frac{v_{f} ^{2}}{R} (3)[/tex]
We have just said that (3) must be equal to the weight:[tex]F_{c} = m*\frac{v_{f} ^{2}}{R} = m*g (4)[/tex]
Simplifying, and rearranging, we can solve for vf², as follows:[tex]v_{f}^{2} = R*g (5)[/tex]
Replacing (5) in (2), simplifying and rearranging in (1) and (2) we finally have:[tex]h_{init} = h_{2} + \frac{1}{2} R = 10m + 7.5 m = 17.5 m (6)[/tex]
what is the reason for timing more than one oscillation in a simple pendulum
Answer:
Time period is the time taken by the body to complete one oscillation and it is noted more than once to get accurate reading from averaging of all the observed values.
given that two vectors A=i,2j-2k and B=6i+3j+2k find A +B
Answer:
7i, 5j, 0k
Explanation:
Add up the two vectors.
Add
i+i 1+6 = 7i
j+j 2+3 = 5j
k+k -2+2 = 0k
therefore A+B = (7i, 5j, 0k)
A) how many cm³ are there in 0.08L?
B) How many dm³ are there in 750mL?
Answer:
A) 80 cm³
B) 0.75 dm³
Explanation:
I hope this help❤️
PLEASE HELP ME WITH ONE QUESTION
If 1000 J of heat energy is lost from a piece of hot metal which is placed into a cup of cool water, how much energy is gained by the water?
Answer:
1000J
Explanation:
According to the law of calorimetry;
Heat lost by cold substance = Heat gained by hot substance
If 1000 J of heat energy is lost from a piece of hot metal,
heat lost by hot substance = 1000J
Since we are to determine how much energy is gained by the water, using the law
Heat lost by hot metal = heat gained by the water
Hence heat gained by the water = 1000J
You want to use a metal bar as a resistor. Its dimensions are 1 by 3 by 13 units. To get the largest resistance from the bar, you should attach leads to the two opposite sides that have dimensions of 1 by 3 units. All configurations give the same resistance. 3 by 13 units. 1 by 13 units. None of the above.
Answer:
1 by 3 units
Explanation:
The resistance (R) of a conductor is given by the formula:
R = ρL / A
where L is the length of the conductor, ρ is resistivity and A is the cross sectional area.
Let us assume that the metal bar has a resistivity of ρ.
a) If the leads is attached to the two opposite sides that have dimensions of 1 by 3 units.
The length of the bar would be 13 units and the cross sectional area (A) would be = 1 * 3 = 3 units²
R₁ = ρL / A = ρ(13) / 3 = 13ρ / 3
b) If the leads is attached to the two opposite sides that have dimensions of 3 by 13 units.
The length of the bar would be 1 units and the cross sectional area (A) would be = 3 * 13 = 39 units²
R₂ = ρL / A = ρ(1) / 39 = ρ / 39
c) If the leads is attached to the two opposite sides that have dimensions of 1 by 13 units.
The length of the bar would be 3 units and the cross sectional area (A) would be = 1 * 13 = 13 units²
R₃ = ρL / A = ρ(3) / 13 = 3ρ / 13
Therefore we can see that the largest resistance is gotten If the leads is attached to the two opposite sides that have dimensions of 1 by 3 units
The microwaves produced inside a microwave have a wavelength of 12.0m and a frequency of 25Hz. At what speed do the microwaves travel in units of m/s ?
Answer: 300 m/s
Explanation:
The equation for finding wave speed is the wavelength times the frequency which would be
12.0mx 25hz=300m/s
Three cylindrical wires, 1, 2, and 3 are made of the same materialand have resistances R1, R2, and R3, respectively. Wires 1 and 2 have the same lengthbut diameter of wire 2 is twice that of wire 1. Wires 2 and 3 have the same diameterbut length of wire 3is twice that of wire 2.
1. Rank the wires according to their resistances, greatest first.
A. R1> R2> R3R1
B. R1> R3> R2R2
C. R2> R1> R3R3
D. R2> R3> R1
E. R3> R1> R2
F. R3> R2> R1Q2.
2. If same voltage is applied across each of the wires, which one will dissipate heat at the highest rate
Answer:
1) R₁ > R₃ > R₂ correct B , 2) the wire that dissipates the most is wire 2
Explanation:
1) The resistance of a wire is given by the expression
R = [tex]\rho \ \frac{l}{A}[/tex]
where ρ is the resistivity of the material, l the length of the wire and A the area of the wire
The area is given by
A = π r² = π d² / 4
we substitute
R = (ρ 4 /π) [tex]\frac{l}{d^2}[/tex]
the amount in parentheses is constant for this case
let's analyze the situation presented, to find the resistance of each wire
* indicate l₁ = l₂ and d₂ = 2 d₁
the resistance of wire 1 is
R₁ = (ρ 4 /π) [tex]\frac{l_1}{d_1^2}[/tex]
the resistance of wire 2 is
R₂ = (ρ 4 /π) \frac{l_2}{d_2^2}
R₂ = (ρ 4 /π) [tex]\frac{l_1}{ (2 d_1)^2}[/tex]
R₂ = (ρ 4 /π ) [tex]\frac{l_1}{d_1^2}[/tex] ¼
R₂ = ¼ R₁
* indicate that d₂ = d₃ and l₃ = 2 l₂
R2 = (ρ 4 /π) [tex]\frac{l_2}{d_2^2}[/tex]
the resistance of wire 3 is substituting the indicated condition
R3 = (ρ 4 /π 2) \frac{l_3}{d_3^2}
R3 = (ρ 4 /π) [tex]\frac{2 \ l_2}{d_2}[/tex]
R3 = 2 R₂
let's write the relations obtained
R₁ = (ρ 4 /π) [tex]\frac{I_1}{ d_1^2}[/tex]
R₂ = ¼ R₁
R₃ = 2 R₂
let's write everything as a function of R1
R₁ =(ρ 4 /π) [tex]\frac{l_1}{d_1^2}[/tex]
R₂ = ¼ R₁
R₃ = ½ R₁
the resistance of the wire in decreasing order is
R₁ > R₃ > R₂
2) The power dissipated by a wire is
P = V I
the voltage is
V = I R
I = V / R
substituting
P = V² / R
therefore the power dissipated by each wire is
wire 1
P₁ = V² / R₁
wire 2
P₂ = V² / R₂
P₂ = [tex]\frac{V^2}{ \frac{1}{4} R_1}[/tex]
P₂ = 4 P₁
wire 3
P₃ = V² / R₃
P₃ = [tex]\frac{V^2}{ \frac{1}{2} R_1}[/tex]
P₃ = 2 P₁
Therefore, the wire that dissipates the most is wire 2
Three 5 Ohm resistors are connected in parallel to a 9 Volt power supply. What is the current through each resistor?
Answer:
I₁ = I₂ = I₃ = 12 A
Explanation:
Since the resistors are connected in parallel across a battery. Hence, the voltage across each of them will be the same, which will be equal to the voltage of the power supply. Since each resistor has the same resistance of 5 Ω. Therefore. the current across each resistor will also be the same. We can easily calculate these current values by the use of Ohm's Law, as follows:
[tex]V = IR\\I_{1}=I_{2}=I_{3}=\frac{V}{R} \\\\I_{1}=I_{2}=I_{3}=\frac{9\ Volt}{5 \Omega}\\\\[/tex]
I₁ = I₂ = I₃ = 12 A
The statement "If a plant receives fertilizer,
then it will grow to be bigger than a plant
that does not receive fertilizer" is an
example of
A. an observation.
B. a hypothesis.
C. a theory.
a box is slides down a slope
Answer:
120 N
Explanation:
From the question given above, the following data were obtained:
Angle (θ) = 35°
Mass (m) = 15 Kg
Acceleration due to gravity (g) = 9.8 m/s²
Normal force (N) =?
The normal force acting on the object can be obtained as:
N = mg × Cosθ
N = 15 × 9.8 × Cos 35
N= 147 × 0.8192
N = 120 N
Therefore, the normal force acting on the object is 120 N
Two resistors R1 = 3 Ω and R2 = 6 Ω are connected in parallel. What is the net resistance in the circuit?
Answer:
2ohms
Explanation:
the net resistance is given by
1/R=1/R1 +1/R2,we are supposed to find R
thus by making R the subject ....
R=R1•R2/R1+R2
R=3•6/3+6
R=18/9 =2Ohms