Answer:
A change in protons changes the element identity. A change in neutrons changes the element's atomic weight, but does not change the identity. More protons than electrons is a positive charge, more electrons than protons is a negative charge.
Explanation:
A stone dropped from the top of a building strikes the ground in 4.2 s. How tall is the building? Someone explain please!
Answer:
well i'm not sure if which unit of measure you need but i think its 86.49 meters tall.
A sprinter can run 100.0 meters in 10.4 seconds. Find the velocity of this runner. (Please put answer into ladder cancellation format!!)
pls help asap pls explain. Just before opening her parachute a skydiver having a mass of 50 kg reaches terminal velocity. Calculate the force of air resistance if the buoyant force is 20 N. Be careful! Use the skydiver’s mass to calculate his/her Fg (force of gravity).
Answer:
490N
Explanation:
Given that,
Mass of a skydiver, m = 50 kg
Buoyant force = 20 N
When the skydiver reaches the terminal velocity, net force on her is equal to 0. So, air drag is equal to the weight of the skydiver.
D = mg
Putting all the values,
D = 50 × 9.8
D = 490 N
So, the force of air resistance is 490 N.
Suppose a boat moves at 12.0m/s relative to the water. If the boat is in a river with the current directed east of 2.50m/s, what is the boat's speed relative to the groiund when it is heading (a) east, with the current, and (b) west, against the current?
Answer:
(a) 14.5 m/s
(b) 9.5 m/s
Explanation:
Let the speed of the boat in the still water (i.e relative to ground) is [tex]v_0[/tex].
Given that the speed of the boat relative to water, [tex]v_r=12.0[/tex] m/s.
Speed of the water current of the river relative to the ground, [tex]u_0=2.50[/tex] m/s towards east.
(a) When the boat is heading toward the east (in the same direction of the current of the river)
The relative velocity, [tex]v_r[/tex], of the boat with respect to ground is
[tex]v_r=v_0-u_0[/tex]
[tex]\Rightarrow 12=v_0-2.5[/tex]
[tex]\Rightarrow v_0=12+2.5=14.5[/tex] m/s
Hence, the boat's speed relative to the ground when it is heading east, with the current, is 14.5 m/s.
(b) When the boat is heading toward the west (in the opposite direction of the current of the river)
The relative velocity, [tex]v_r[/tex], of the boat with respect to ground is
[tex]v_r=v_0-(-u_0)[/tex]
[tex]\Rightarrow 12=v_0+2.5[/tex]
[tex]\Rightarrow v_0=12-2.5=9.5[/tex] m/s
Hence, the boat's speed relative to the ground when it is heading west, against the current, is 9.5 m/s.
1.Why is wheel and axle a simple machine?
2.What is meant by effort is multiplied?
Answer:
The wheel and axle is a type of simple machine used to make tasks easier in terms of manipulating force by applying the concept of mechanical advantage.Due to the size difference in the radius of the wheel and axle, this means that the distance the two parts rotate through in the same amount of time is different.
If a car accelerates at a uniform 4.0 m/s, how long will it take to reach a speed of 36.0 m/s,
starting from rest?
Answer:
9s
Explanation:
v=u+at
36=0+4t
t=36-0/4
t=9s
What is meant by the term total internal reflection? What two conditions must be met for total internal reflection to occur?
Answer:
Hello....
Explanation:
Total internal reflection, in physics, complete reflection of a ray of light within a medium such as water or glass from the surrounding surfaces back into the medium. The phenomenon occurs if the angle of incidence is greater than a certain limiting angle, called the critical angle.
The conditions required for total internal reflection (TIR) to occur are:
1)the light must be travelling from a more dense medium into a less dense medium (ie glass to air)
2)the angle of incidence must be greater than the critical angle.
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Look at pic.... 2 examples of radiation and how they are radiation
Answer:21
Explanation:
Lucy and JoJo need to make 140 cupcakes for the school dance. Lucy made 35 of the cupcakes. JoJo made 42 cupcakes What fraction of the cupcakes do Lucy and JoJo still need to make?
Answer:
9/20
Explanation:
According to this question, Lucy and JoJo need to make 140 cupcakes for the school dance. Lucy made 35 of the cupcakes while JoJo made 42 cupcakes. This means that in total, (42 + 35) cupcakes has been made by both Lucy and JoJo
That is, 77 cupcakes out of 140 has been made. This is 77/140 i.e. 11/20
Since 77/140 cupcakes has been made, Lucy and JoJo still need to make;
140 - 77 = 63 cupcakes to meet up their target for the school dance.
This means that the fraction left is 63/140
63/140 in its lowest term is 9/20
Hence, 9/20 of the cupcakes still need to be made by Lucy and JoJo.
Explanation: 140 - 35 = 105 - 42 = 63
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Which characteristic is related to kinetic energy but not potential energy?
A. An object's shape
B. An object's mass
C. An object's speed
D. An object's height
Answer:
c
Explanation:
An object's speed is the characteristic which is related to kinetic energy but not the potential energy. Thus, the correct option is C.
What is Kinetic energy?The kinetic energy of an object is the energy which it possesses due to the motion of the object. Kinetic energy is defined as the work which is needed to accelerate an object of a given mass from rest position to its stated velocity. Having gained this amount of energy during the acceleration of the object, the object maintains this kinetic energy unless its speed changes or it experiences acceleration.
Kinetic energy is directly proportional to the mass of the object and to the square of the velocity of the object, the expression is:
K.E. = 1/2 m × v²
where, KE = Kinetic energy,
m = mass of the object,
v = velocity of the object.
Therefore, the correct option is C.
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he lower the frequency of the wave the ____________ it will have.
a
more medium
b
more energy
c
more amplitude
d
less energy
Explanation:
D. Less Energy
The more energy in a wave, the higher it's frequency
The less energy in a wave, the lower the frequency is
A model railroad train travels at a constant speed of 8 cm/s . How far would the train travel in one minute ?
Answer:
Answer:
480cm or 0.48m
Explanation:
Given parameter:
Speed of the train = 8cm/s
time of travel = 1minute
Unknown:
Distance traveled = ?
Solution:
Speed is the rate of change of distance with time. This suggests that mathematically;
Speed =
Distance covered = speed x time
Now to solve for the distance;
Convert the time to seconds;
60seconds = 1 minute
Distance covered = 8cm/s x 60s = 480cm
Distance covered is 480cm or 0.48m
A car travels at a constant speed of 70 km/hr for 15 minutes. The car decreases its speed from 70 to 40 km/hr over the next two minutes and then continues to travel at a constant speed of 40 km/hr for the next 5 minutes Which of the following graphs best represents the car's motion during the given time period?
Answer:
A car travels at a constanT
Scientists have changed the model of the atom as they have gathered new evidence. One of the atomic models is shown below.
A purple center outlined in black with two concentric black circles around the center, the inner circle having 2 small green balls on it and the outer circle having 8 small green balls on it.
What experimental evidence led scientists to change from the previous model to this one?
A few of the positive particles aimed at a gold foil seemed to bounce back.
The colors of light emitted from heated atoms had very specific energies.
Experiments with water vapor showed that elements combine in specific proportions.
Cathode rays were bent in the same way whenever a magnet was brought near them.
Answer:
B: The colors of light emitted from heated atoms had very specific energies.
Explanation:
In Thompson's model of an atom the atom is said to be constituted of electrons which are surrounded by a haze of positive charge in order to balance the electrons' negative charges. It is also called plum prodding model because of negatively charged plums which are surrounded by the positively charged pudding.
Now, as the electrons move from higher to lower energy levels a photon which is a particle of light will be given off.
Thus, the correct answer is option B
Answer:
B: The colors of light emitted from heated atoms had very specific energies.
Explanation:
An object on another planet with g = 25 m/s^2 hits the ground from rest in 4 seconds. How far did it fall?
Choices:
•200.0m
•100.0m
•1000.0m
•25.0m
3. A person who is initially stationary is eventually walking
at a speed of 1.5 m/s after an acceleration of 0.5 m/s?,
calculate the distance it takes them to reach this speed.
4. A lorry pulls forward after initially being stationary, it
takes the lorry 40 m to reach a speed of 8 m/s, calculate the
lorry's acceleration.
7. A person begins moving after initially being stationary, the person
accelerates at 0.5m/s2 over a distance of 9m what is their final speed
Explanation:
3. A person who is initially stationary is eventually walking
at a speed of 1.5 m/s after an acceleration of 0.5 m/s?,
calculate the distance it takes them to reach this speed.
Given parameters:
Initial velocity = 0m/s
Final velocity = 1.5m/s
Acceleration = 0.5m/s
Unknown:
Distance = ?
Solution:
To solve this problem, we apply the relevant motion equation;
V² = U² + 2aS
where V is the final velocity
U is the initial velocity
a is the acceleration
S is the distance
Input the parameters;
1.5² = 0 + 2 x 0.5 x S
2.25= S
The distance to reach this speed is 2.25m
4. A lorry pulls forward after initially being stationary, it
takes the lorry 40 m to reach a speed of 8 m/s, calculate the
lorry's acceleration.
Given parameters:
Initial velocity = 0m/s
Final velocity = 8m/s
Distance = 40m
Unknown:
Acceleration = ?
Solution:
V² = U² + 2aS
Input the parameters and solve;
8² = 0² + 2 x a x 40
64 = 80a
a = [tex]\frac{64}{80}[/tex] = 0.8m/s²
7. A person begins moving after initially being stationary, the person
accelerates at 0.5m/s2 over a distance of 9m what is their final speed
Given parameters:
Initial velocity = 0m/s
acceleration = 0.5m/s²
distance = 9m
Unknown:
Final velocity = ?
Solution:
V² = U² + 2aS
Input the parameters and solve;
V² = 0² + 3 x 0.5 x 9
V² = 13.5
V = 3.7m/s
which of the following is the same as 1 second
Answer:
theres no
Explanation:
picture or anything so... ur question doesnt make sense
Consider a buggy being pulled by a horse.
Which is correct?
1. The horse can pull the buggy forward only
if the horse weighs more than the buggy.
2. The force on the buggy is as strong as the
force on the horse. The horse is joined to the
Earth by flat hoofs, while the buggy is free to
roll on its round wheels.
3. The horse pulls before the buggy has time
to react so they move forward.
4. The horse pulls forward slightly harder
than the buggy pulls backward on the horse,
so they move forward.
Answer:
Option 2
Explanation:
Answer:B
Explanation:because she started of with no money and now she made her money up
How do Newton's and Kepler's laws apply to galaxies(or galaxy collisions)?
Answer:
Newton's Laws of Motion
If Kepler's laws define the motion of the planets, Newton's laws define motion. Thinking on Kepler's laws, Newton realized that all motion, whether it was the orbit of the Moon around the Earth or an apple falling from a tree, followed the same basic principles.
The sum of potential energy and kinetic energy is
Answer:
The total mechanical energy
Explanation:
M = Mass
V = Velocity
G = Gravity
H = Height
KE = 1/2mv²
PE = mgh
ME = KE + PE
ME = 1/2 mv² + mgh
If an object is moving up, is it considered to have a positive or negative velocity?
Answer:
A positive velocity
Explanation:
A car is said to go "zero to sixty in six point six
seconds" (0 to 60 mph in 6.6 seconds). What is its
acceleration in m/s??
5 grams is thes than greater than or equal too 508mg
Answer:
yes 5 is greater
Explanation:
Answer: 5 grams is greater than 508 milligrams. Even though the number '508' is larger than '5,' you need to look at the units.
A boat covered 5/9 of a journey at an average speed of 25
mph. Then, it travelled the remaining 120 miles at another
speed. If the total time of the whole journey was 8.5 hours,
what was the amount of time the boat spent on the remaining
120 miles? (Write as a decimal.)
_____ hours
Need it for now
Answer:
Thus, the time for the remaining 120 miles: 8.5 - 6 = 2.5 h
Explanation:
The remaining 120 miles was (1 - 5/9 = 4/9) of the total journey.
Then, total distance: 120 ÷ 4/9 = 120 × 9/4 = 270 miles
The distance for 25 mph: 270 × 5/9 = 150 miles
The time for 25 mph: 150 ÷ 25 = 6 h
The boat spent 2.5 hours on the remaining 120 miles.
What is speed?Speed is distance travelled by the object per unit time. Due to having no direction and only having magnitude, speed is a scalar quantity With SI unit meter/second.
According to the question, The remaining 120 miles was (1 - 5/9) = 4/9of the total journey.
Then, total distance travelled by the boat: 120 ÷ 4/9 = 120 × 9/4 = 270 miles.
The distance travelled by the boat at 25 mph: 270 × 5/9 = 150 miles.
The time taken to travel this distance: 150 ÷ 25 = 6 hours.
Hence, the time for the remaining 120 miles is: 8.5 - 6 = 2.5 hours.
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what is the distance from letter D to A?
Answer:
5 is a correct Answer iiiiiiiiiii
match the letter with the layer
Answer:
Thermosphere A,B
Mesosphere B,C,D
Stratosphere D,E,F
Troposphere G
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If an object starts accelerating from rest at a rate of 35 m/s2, then how far does it travel during the first second?
List out Units For: Acceleration
Unit for Acceleration is m/s² or ms raised to -2
A force of 500 N acts for a time interval of 0.001 second on an object of mass 0.20 kg that was initially at rest. Calculate the final velocity of the object after the force acts
Answer:
100
Explanation:
The final velocity of the object after the force acts is 2.5 meters per second.
To calculate the final velocity of the object after the force acts, we can use Newton's second law of motion, which states that:
Force = Mass × Acceleration
We need to find the acceleration of the object first. Since the object was initially at rest, its initial velocity (u) is 0 m/s.
The force acting on the object is 500 N, and the mass of the object is 0.20 kg. We can rearrange the equation to find the acceleration (a):
Acceleration (a) = Force / Mass
a = 500 N / 0.20 kg
a = 2500 m/s²
Now, we can use the kinematic equation to find the final velocity (v) of the object:
Final velocity (v) = Initial velocity (u) + (Acceleration × Time)
The initial velocity (u) is 0 m/s (since the object was initially at rest), and the time interval (t) is 0.001 second.
Final velocity (v) = 0 m/s + (2500 m/s² × 0.001 s)
v = 0 m/s + 2.5 m/s
v = 2.5 m/s
Hence, the final velocity of the object after the force acts is 2.5 meters per second.
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Which scenario does not describe an example of acceleration?
A car increases its speed while turning to the left.
A car decreases its speed while driving straight ahead.
A car maintains a constant speed while turning to the right.
A car maintains a constant speed while driving straight ahead.
Answer:
B is the right answer
Explanation:
It is decreasing.
A car maintains a constant speed while driving straight ahead.
What is acceleration?The acceleration of an object is the rate of change of velocity with time. It is measured in meter per second square.
Velocity of the carThe car undergoes velocity when there is change in direction of the speed.
Thus, the only option that does not describe acceleration is a car maintains a constant speed while driving straight ahead.
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