Answer:
The speed of an object
11. How fast will a pebble be traveling 3 seconds after being dropped? (g = 9.8 m/s2)
A.-9.8 m/s
B.29.4 m/s
C.9.8 m/s2
D.29.4 m/s
When living things use chemical reactions to break down food, some of the energy is transformed into
OA. sound.
OB. heat.
OC. light
OD.waste
waste.
Answer:
OB. Heat
Explanation:
I hope this helped :)
Its velocity changes at different time intervals. Calculate the instantaneous
velocity at time 3 sec. The distance is given by equation 2t² – 4t
Answer:
The instantaneous velocity at time 3 sec is 8 (no units specified).
Explanation:
Instantaneous Velocity
The instantaneous velocity of an object is the derivative of the distance function with respect to time.
The distance is given by the function:
[tex]x(t)=2t^2 - 4t[/tex]
Now we compute the instantaneous velocity function by taking the derivative of x:
[tex]\displaystyle v(t) = \frac{dx}{dt}[/tex]
[tex]\displaystyle v(t) = \frac{d(2t^2 - 4t)}{dt}[/tex]
[tex]v(t) =4t -4[/tex]
Now evaluate the velocity for t=3 sec:
[tex]v(3) =4(3) -4[/tex]
[tex]v(3) =12 -4 = 8[/tex]
The instantaneous velocity at time 3 sec is 8 (no units specified).
Dr. Metallica wants to change the property of an alloy? How could she do this? SELECT ALL THAT APPLY.
A. She could heat the alloy enough that it is malleable.
B. She could change the metal(s) used in the alloy.
C. She could change the nonmetal(s) used in the alloy.
D. She could change the percentages of the elements used in the alloy.
Answer:
METALLICA = HOT BAND
Explanation:
The answer is a, you're welcome babes
Answer: A B D
Explanation:
how can voltage be produced by magnetism and motion?
Answer:
Electromagnetic Induction by a Moving Magnet
Then the action of moving a coil or loop of wire through a magnetic field induces a voltage in the coil with the magnitude of this induced voltage being proportional to the speed or velocity of the movement.
Explanation:
A child sits on a merry-go-round, 1.5 meters from the center. The merry-go-round is turning at a constant rate, and the child is observed to have a radial acceleration of 2.3 m/s2. How long does it take for the merry-go-round to make one revolution
Answer:
5 .07 s .
Explanation:
The child will move on a circle of radius r
r = 1.5 m
Let the velocity of rotation = v
radial acceleration = v² / r
v² / r = 2.3
v² = 2.3 r = 2.3 x 1.5
= 3.45
v = 1.857 m /s
Time of revolution = 2π r / v
= 2 x 3.14 x 1.5 / 1.857
= 5 .07 s .
The merry-go round will take 5.07 s to complete one complete revolution.
Given data:
The distance of child from the center is, r = 1.5 m.
The magnitude of radial acceleration is, [tex]a = 2.3 \;\rm m/s^{2}[/tex].
Since, the child is on merry-go round, which is undergoing a rotational motion. And radial acceleration means that it is under the acceleration, whose value is given as,
[tex]a=\dfrac{v^{2}}{r}\\\\v=\sqrt{a \times r}[/tex]
Here, v is the linear velocity.
Solving as,
[tex]v=\sqrt{2.3 \times 1.5} \\\\v=1.857 \;\rm m/s[/tex]
Now, we to obtain the time taken by merry-go round to complete one revolution. Then the expression for the time taken to complete one revolution is,
[tex]T=\dfrac{2 \pi r}{v}\\\\T=\dfrac{2 \pi \times 1.5}{1.857}\\\\T = 5.07 \;\rm s[/tex]
Thus, we can conclude that the merry-go round will take 5.07 s to complete one revolution.
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A horizontal force of 100 N is applied to move a 50-kg cart (initially at rest) across a 10 m level surface. What is the final kinetic energy of the cart?
The net force on the cart is 100 N in the direction of its motion, so by Newton's second law we can find the acceleration a applied to it:
100 N = (50 kg) a
a = (100 N) / (50 kg)
a = 2 m/s²
The cart starts at rest and travels a distance of 10 m, so that its final velocity v satisfies
v ² - 0² = 2 (2 m/s²) (10 m)
v ²= 40 m²/s²
and so the cart ends up with kinetic energy
KE = 1/2 m v ² = 1/2 (50 kg) (40 m²/s²) = 1000 J
How long would it take a car, starting from rest and accelerating uniformly in a straight line at 5m/s^2, to cover a distance of 200m?
Answer:
The time taken by the car is 8.94 seconds.
At what condition does a body becomes weightless at the equator?
Answer:
The decrease is due to the bulge at the equator (putting more distance between the rest of the planet and the surface
Explanation:
what energy transfer will a stretched rubber band have when let go
Answer:
when the rubber band is realeased the potential energy is quickly converted to kinetic energy this is equal to one mass of the the rubber band multiplied by its velocity( in meters per second)
Which statement correctly describes the diferences between positive and negative acceleration
O Positive acceleration describes a change in speed, negative acceleration desxibes no change in speed,
Positive acceleration describes no change in speed, negative acceleration desibes a change in speed,
Positive acceleration describes an increase in speed, negative sexeleration desnibes a decrease in speed
O Positive acceleration describes a decrease in speed, negative sideration describes an increase in sarees
Answer:The answer is this Positive acceleration describes an increase in speed, negative sexeleration desnibes a decrease in speed
Explanation:
which two conditions would result in the strongest electric force between charged objects
Answer:
A and B
Explanation:
The two conditions which results in the strongest electric force between charged objects are when they close together secondly, when the objects are conductors with balanced charges.
What is electric force ?Electric force is the force generated between charged bodies. There are both repulsive and attractive electric forces. Like charges exerts a force of repulson between each other. Unlike charges will exert an attractive force between each other.
According to Coulomb's law of electric forces is directly proportional to the magnitude of charges and inversely proportional to the distance between them. Thus , when the objects are closer the greater force is exerted between them.
Insulators does not allow flow of free electrons and the electric force between them is weak. Whereas, when two conductors of unlike charges exerts strong electrostatic force of attraction. Hence, option B and C are correct.
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A 300 g object attached to a horizontal spring moves in simple harmonic motion with a period of 0.340 s. The total mechanical energy of the spring–object system is 3.00 J.
(a) What is the spring constant (in N/m)?
(b) What is the amplitude (in m) of the motion?
(c) What is the percentage change in amplitude of motion if the total energy of the system is increased to 5.00 J?
Answer:
Explanation:
angular velocity ω = 2π / T where T is time period of rotation .
= 2 x 3.14 / .34 = 18.47 rad /s
Total mechanical energy = 1/2 m ω²Α² where A is amplitude .
spring constant = k
[tex]\omega=\sqrt{\frac{k}{m} }[/tex]
m is mass
[tex]\omega^2=\frac{k}{m} }[/tex]
18.47² = k / .3
k = 102.34 N /m
b )
energy = 1/2 m ω²Α²
3 = .5 x 18.47² x A²
A² = .01759
A = .1326
13.26 cm .
c )
If energy becomes 5 J
5 = .5 x 18.47² x A²
A² = .0293
A = .1711
= 17.11 cm
percent increase
= (17.11 - 13.26 )x100 / 13.26
= 29%
An artery with cross sectional area of 1 cm2 branches into 20 smaller arteries each with 0.5 cm2 cross sectional area. If the velocity of blood in the thicker artery is v, what is the velocity of the blood in the thinner arteries
Answer:
The velocity of the blood in the thinner arteries is 0.1 times that of the thicker artery.
Explanation:
To find the velocity of the blood we need to use the continuity equation:
[tex] n_{1}A_{1}v_{1} = n_{2}A_{2}v_{2} [/tex] (1)
Where:
n: is the number of branches
A: is the cross-sectional area
v: is the velocity
For artery 1, we have:
n₁ = 1, A₁ = 1 cm², v₁ = v
For the 20 arteries (2), we have:
n₂ = 20, A₂ = 0.5 cm², v₂ =?
By using equation (1):
[tex] n_{1}A_{1}v_{1} = n_{2}A_{2}v_{2} [/tex]
[tex] 1 cm^{2}*v = 20*0.5 cm^{2}*v_{2} [/tex]
[tex] v_{2} = \frac{1 cm^{2}*v}{20*0.5 cm^{2}} = \frac{v}{10} = 0.1v [/tex]
Therefore, the velocity of the blood in the thinner arteries is 0.1 times that of the thicker artery.
I hope it helps you!
Someone help me please it’s urgent
When water changes from a gas in the atmosphere to a liquid droplet in a cloud, this is known as
Group of answer choices
transpiration
condensation
evaporation
precipitation
Answer:
Condensation
Explanation:
Answer:When water changes from a gas in the atmosphere to a liquid droplet in a cloud, this is known as
Group of answer choices
transpiration
condensation
evaporation
precipitation,←, that one is right
Explanation: so ur answer is precipitation
Is a compound considered a pure substance?
Answer:
It depends on which compound you use carbon dioxide can be while helium will not but if you where to sum it up it would be use because simply most compounds are considered pure substance.
Explanation:
Rita wants to make some toast for breakfast, which she knows involves a chemical change to the bread.
She puts a slice of bread in the toaster, but, after 10 minutes, she notices that the sides of the bread are
black. What caused this chemical change to go too far?
A. an increase in temperature
B. a decrease in temperature
C. the size of the bread
D. the type of bread
Answer:
A
Explanation:
The toaster was too high so its the increase in eat
A 2,000 kg car travels with a tangential
velocity of 12 m/s around a circular
track with a radius of 30 meters. What
is the car's rate of centripetal
acceleration?
The car's rate of centripetal acceleration in the circular path is 4.8 m/s².
The given parameters;
mass of the car, m = 2,000 kgvelocity of the car, v = 12 m/sradius of the circular path, r = 30 mThe centripetal acceleration of the car is calculated as follows;
[tex]a_c = \frac{v^2}{r}[/tex]
where;
v is the tangential speed of the carr is the radius of the circular pathSubstitute the given parameters and solve for the centripetal acceleration;
[tex]a_c = \frac{12^2}{30} \\\\a_c = 4.8 \ m/s^2[/tex]
Thus, the car's rate of centripetal acceleration is 4.8 m/s².
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Impact extinction 65 million years ago over 50% of all species became extinct, ending the reign of dinosaurs and opening the way for mammals to become the dominant land vertebrates. A theory for this extinction, with considerable supporting evidence, is that a 10-km-wide 1.8×1015kg asteroid traveling at speed 11 km/s crashed into Earth.
A) Determine the change in velocity of Earth due to the impact. Mass of Earth is 5.98×1024kg.
B) Determine the average force that Earth exerted on the asteroid while stopping it. Assume that stopping distance is 0.60 km (depth of the crater created)
C) Determine the internal energy produced by the collision (a bar chart for the process might help). By comparison, the atomic bombs dropped on Japan during World War II were each equivalent to 15,000 tons of TNT (1 ton of TNT releases 4.2×109J of energy).
Answer:
for a)
Explanation:
(1.8 x 10^15)(11 x 10^3 m/s) = (5.98 x 10^24 + 1.8 x 10^15)vf
vf= (1.8 x 10^15)(11 x 10^3 m/s) / (5.98 x 10^24 + 1.8 x 10^15)
= 3.3×10−6 m/s
Which of these is a base?
HNO3
vinegar
ammonia
HCl
The correct answer is Ammonia
b. Interpret Data Solution A has a pH of 1.6.
Solution B has a pH of 4. Which solution
has a greater concentration of hydrogen
ions? Explain.
Answer:
Solution A has a pH of 6 and solution B has a pH of 8. Which of the following is true regarding the concentration of hydrogen ions in each solution? A) A has 100 times greater H+ concentration than B. B) B has 100 times greater H+ concentration than A. C) A has 7/9 of the H+ concentration of B. D) A has 9/7 of the H+ concentration of B. E) none of these
Explanation:
Hey im super sorry if i get this wrong :)
1. A person weighs 155 lbs and is walking 3.1 miles per hour. How much kinetic energy does the person have? (Keep in mind, 1 kg is 2.2 lb, and 1 m/s is 2.24 mi/h.)2. What is the kinetic energy of a 5 g bullet travelling 400 m/s?
3. Is it possible to have a negative KE? Why or why not?
Answer:
Explanation:
Kinetic energy is expressed as;
KE =1/2 mv²
M is the mass
v is the velocity of the object
1) Given
Mass = 155lb
Velocity = 3.1mi/hr
Since 1kg = 2.2lb
x = 155lb
x= 155/2.2
x = 70.45kg
Also
1m/s = 2.24mi/hr
y = 3.1mi/hr
y = 3.1/2.24
y = 1.384m/s
KE = 1/2(70.45)(1.384)²
KE = 0.9577×70.45
KE = 67.47Joules
2) M = 5g =0.005kg
V = 400m/s
KE = 1/2(0.005)400²
KE = 80000×0.005
KE = 400Joules
3} Since a body decelerates (negative acceleration) this mean that the velocity of a body can be a negative value showing that it is possible for a moving body to possess negative kinetic energy.
The engine of a boat (m = 2280 kg) exerts an
1800 N force northward, while the current
pushes it 1050 N eastward.
What is the magnitude of the acceleration
of the boat?
Answer:
a = 0.9139 [m/s²]
Explanation:
To solve this problem we must use Newton's second law, which tells us that the sum of forces on a body is equal to the product of mass by acceleration.
The forces are on two different axes, x & y axes (North and East). In this way, the Pythagorean theorem should be used to determine the total force.
Fx = 1800 [N]
Fy = 1050 [N]
[tex]F = \sqrt{(F_{x} )^{2} +(F_{y} )^{2} } \\F=\sqrt{(1800)^{2} +(1050)^{2} } \\F=2083[N][/tex]
Now using Newton's second law.
ΣF = m*a
where:
F = force = 2083.8 [N] (units of Newtons)
m = mass = 2280 [Kg]
a = acceleration [m/s²]
2083.8 = 2280*a
a = 0.9139 [m/s²]
A jogger runs 4 km in 0.4 hr, then 8 km in 0.8 hr. What is the average speed of the jogger?
The jogger would have ran about 10 km/h.
PLZ HELP help me help help
Answer:
matter
Explanation:
Hope I helped :)
Please answer ASAP, and please don't joke around and actually do answer my question. I will give you brainliest if you answer it well:
A girl, standing on a bridge, throws a stone vertically downward with an initial velocity of 12.0 m/s, into the river below. If the stone hits the water 2.50 seconds later, what is the height of the bridge above the water?
Remember to identify all your data, write the equation, and show your work.
Answer:
30 feet
Explanation:
First off, if they are throwing at 12.0 m/s and it takes 2.5 seconds. It will be the act of multiplication.
12 times 2.5 is 30, because 12 times 2 is 24 plus 12 divided by 2 which is 6 so 24 plus 6 is 30.
Having been kicked, a soccer ball rolls past a kid with a stopwatch. At the moment the ball passes the kid, it has an initial velocity of 4.0 m/s and the watch reads 10.0 s. If the watch reads 23.3 s when the ball stops rolling, what is its average acceleration?
The ball rolls to a rest from 4.0 m/s in a span of 23.3 s - 10.0 s = 13.3 s, so the average acceleration is
(0 - 4.0 m/s) / (13.3 s) ≈ -0.30 m/s²
A baseball is thrown horizontally with a velocity of 44 m/s. It travels a horizontal distance of 18
m to the plate before it is caught. How long does the ball stay in the air?
A.0.41 sec
B.41 sec
C.4.1 sec
D.4 sec
Answer:
a 0.41
plug number into equation
A horizontal baseball pitch is launched at 44 m/s. The ball will stay for 4.1 sec (approx) in the air. Hence, option C is correct.
What is Velocity?The rate at which an object's position changes when observed from a specific point of view and when measured against a specific unit of time is known as its velocity.
Its SI unit is represented as m/s, and it is a vector quantity, it means that it has both magnitude and direction.
According to the question, the given values are :
Initial Velocity, u = 44 m/s,
Distance travelled, s = 18 m and,
Final velocity, v = 0.
Use equation of motion :
v = u + at
0 = 44 + (-9.8)t
t = 44 / 9.8
t = 4.3 (approx)
Hence, the time for which the ball stay in the air is 4.1 sec (approx).
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A toaster is rated at 600W, when connected to a120-V source. What current does the toaster carry, and what is its resistance?
Explanation:
Given parameters:
Power of the toaster = 600W
Voltage = 120V
Unknown:
Current = ?
Resistance = ?
Solution:
The power in the circuit is related to resistance and current using the expression below;
P = IV
P = [tex]\frac{V^{2} }{R}[/tex]
P is the power
I is the current
V is the voltage
R is the resistance
To find the current;
I = [tex]\frac{P}{V}[/tex] = [tex]\frac{600}{120}[/tex] = 5A
Now, resistance;
V² = PR
R = [tex]\frac{V^{2} }{P}[/tex] = [tex]\frac{120^{2} }{600}[/tex] = 24ohms
Current, I=5A
Resistance, R=24 ohms
Firstly, let's write the given values:
Power, P=600W
Voltage, V=120V
To find:
Current, I=?
Resistance, R=?
Lets understand ohm's Law:
Ohm's law states that the current through a conductor between two points is directly proportional to the voltage across the two points.
Formula for Ohm's law:
[tex]V=I.R[/tex]
The relation between power, current and resistance can be represented as:[tex]P=I.V[/tex]
Or
[tex]P=\frac{V^2}{R}[/tex]
To find current:
[tex]I=\frac{P}{V}[/tex]
So on substituting given values,
[tex]I=\frac{600}{120} =5A[/tex]
To find resistance:
[tex]R=\frac{V^2}{P}[/tex]
So on substituting given values,
[tex]R=\frac{14400}{600} =24 \text{ohms}[/tex]
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