Answer:
Before the collision:
m v1 = .5 kg * 15 m/s = 7.5 kg-m/s
Incidentally, after the collision
(M + m) v2 = 7.5
v2 = 7.5 / (1 + .5) = 5 m/s
A book with a mass of 2 kg sits on top of a book shelf at a height of 3 m. How much potential energy does the book have
Answer:
Answer is 98 joules
Explanation:
P. E=2*9.8*3=98
S.i unit of potential energy ⚡ is joules
So answer is 98 joules
PLS HELPP HURRYYY
The trapdoor swings open and the ball falls to the ground. The ball does not bounce when it hits the ground. Show that the final speed of the ball at the instant before it hits the ground is about 5 m/s.
Answer:
5 m/s
Explanation:
As the ball falls to the ground, it is acted upon by a force which is due to the gravitational force. Hence, the ball falls with an acceleration called the acceleration due to gravity.
Let us assume that the acceleration due to gravity (g) = 10 m/s², Since initially, the body was at rest, hence the initial velocity (u) = 0 m/s. The height to the ground (h) = 1.3 m. Hence using the equation of motion, the final velocity (v) is:
v² = u² + 2gh
Substituting:
v² = 0² + 2(10)(1.3)
v² = 26
v = √26 = 5
v = 5 m/s
Answer this question fast please
Which of the following physical quantity is having same SI units?
a) Speed and average speed
b) Speed and velocity
c) Speed and average velocity
d) All the above
Answer:
d) All the above
Explanation:
Speed SI unit is metre per second.Velocity SI unit is metre per second.Average speed SI unit is metre per second.Average velocity SI unit is metre per second.Therefore, as all of the physical quantities have the same SI units, the answer is d) all of the above.
1. 10. waves break on the beach in 2.0 min. What is the frequency in hertz of these waves (cycles per
second)? What is the time between successive waves, in seconds?
Answer:
there it is fella tried o. ma own consciousness
Sound travels slowest through gases _____________________. Group of answer choices because the molecules of gas are close together because gases are air because the molecules of gas are far apart because gases have the lowest temperature
I need help with this science question, 50 points!
Answer:
an open circuit (A battery, bulb, wire,switch)
Explanation:
the battery supplies the power the wire carries the current from the battery to the bulb but the circuit is not completed if the switch is not connected (Switch )
Ponds and lakes are part of marine ecosystem.
True or false ?
Answer:
True
Explanation:
because they can hold marine organism inside
Si un automóvil logra una potencia util promedio de 250kw y se sabe que tiene un rendimiento energético del 25%. ¿Cuanta energia total consume en 1 min? Exprese el resultado en kj
Answer:
W = 3.75 kJ
Explanation:
Power is defined by the relational
P = W / t
W = P t
the yield is 25% = 0.25
W = 0.25 Wo
W = 0.25 250 60
W = 3750 J
W = 3.75 kJ
give reason for the following observation
The smell of hot sizzling food reaches you several metres away but to get the smell from cold food you have to go close.
Answer: The smell of hot sizzling food reaches you several metres away, but to get the smell from cold food you have to go close because the kinetic energy of the particles of matter increases with the increase in temperature. In cold foods, kinetic energy is less while in hot foods, kinetic energy is more
hope this helps
Smell spreads due to diffusion. In hot food the molecules have a lot of kinetic energy , and they therefore spread fast , whereas in cold food the kinetic energy of the molecules are less and they don't spread far.
I need help pleaseee
Answer:
a refraction
b reflection
creflection
d refraction
brainliest plzz
Select all the correct answers. Which statements about potential energy are true?
Answer: The statement gaining potential energy is always associated with a force field, is true about potential energy.
Explanation:
The energy acquired by an object due to its position is called potential energy.
Basically, a force field exerts a force that gives rise to potential energy of an object. For example, gravity, spring force etc.
This means that gaining potential energy is always associated with a force field.
A change in position does not always means that an object gains potential energy. For example, a spring will have more potential energy when it is compressed or stretched.
Hence, change in position of an object not necessarily means always gain in potential energy.
There are two types of potential energy that is, gravitational potential energy and elastic potential energy.
Thus, we can conclude that the statement gaining potential energy is always associated with a force field, is true about potential energy.
Answer:
Explanation:
The first one and the last one are the correct answer.
how can you reduce output voltage to 6v in transformers if the input voltage is 240v
Answer:
[tex]N_P = 40\ N_S[/tex]
To reduce the output voltage to 6v in transformers if the input voltage is 240v, we need to have 40 times as many turns in the primary coil as there are in the secondary coil.
Explanation:
The change in voltage of a transformer depends upon the turns ratio of the transformer between secondary and primary coil. Following formula can be used to determine the turns ratio in this case:
[tex]\frac{N_P}{N_S} = \frac{V_P}{V_S} \\\\[/tex]
where,
[tex]N_P[/tex] = No. of turns in the primary coil
[tex]N_S[/tex] = No. of turns in the secondary coil
[tex]V_P[/tex] = voltage in the primary coil = 240 V
[tex]V_S[/tex] = voltage in the secondary coil = 6 V
Therefore,
[tex]\frac{N_P}{N_S} = \frac{240\ V}{6\ V} \\\\N_P = 40\ N_S[/tex]
To reduce the output voltage to 6v in transformers if the input voltage is 240v, we need to have 40 times as many turns in the primary coil as there are in the secondary coil.
The atomic mass of calcium is 40.08. What is the mass of 6.02 × 1023 atoms of calcium?
Answer:
It is 40.08 g
Explanation:
[tex]6.02 \times 10 {}^{23} \: atoms = 1 \: mole = 40.08 \: g[/tex]
An electrical heating coil is immersed in 4.6kg of water 22°C.The coil, which has a resistance of 250Ω, warms the water to 32°C in 15min. What is the potential difference at which the coil operates?
Answer:
242.4 V
Explanation:
Applying,
Q = cm(t₂-t₁)................ Equation 1
Where Q = amount of heat, c = specific heat capacity, m = mass, t₁ = initial temperature, t₂ = final temperature.
But this heat is produced by electrical power
Therefore,
P = Q/t
Where P = Electrical power, t = time
Also,
P = V²/R
Where V = voltage, R = resistance
Therefore
V²/R = Q/t......................... Equation 2
Substitute equation 1 into equation 2
V²/R = cm(t₂-t₁)/t................. Equation 3
Given: R = 250 ohms, m = 4.6 kg, t₁ = 22°C, t₂ = 32°C, t = 15 min. = (15×60) = 900 seconds
Constant: c = 4600 J/kg.°C
Substitute these values into equation 2
V²/250 = 4600(4.6)(32-22)/900
V²/250 = 235.11
V² = 250×235.11
V² = 58777.78
V = √58777.78
V = 242.4 V
find out the speed of the car from home to school in meters per second.
Time - 15 mins
Distance - 8 km
1.875
Explanation:
speed = distance moved ÷ time taken
Which property of the coating on fiber-optic strands makes light visible only at the ends of the strands?
reflectivity
absorbency
transparency
translucency
The answer is A, Hope this helps and sorry for being late :)
The total momentum before a collision is___to the total momentum after a collision
Answer:
Equal
Explanation:
The law of conservation of energy states that the total momentum before and after a collision are equal
Answer:
Equal to the total momentum of the two objects after the collision.
A scientist is examining an unknown solid. Which procedure would most likely help determine a chemical property of the substance?
heating it to find the temperature at which it melts
exposing it to a flame to see if it catches on fire
hitting it with a hammer to determine if it breaks or bends
placing it in water to find out whether or not it dissolves
Answer:
hitting it with a hammer to determine if it breaks or bends
Answer:
exposing it to a flame to see if it catches on fire
Explanation:
A chemical property is when the matter changes into a different substance. This is true when you expose it to a flame because if a substance is burned, it will change into a new substance. All the other options are examples of physical changes.
-I also took the quiz and got 100%
Hope this helps!
6. A ball rolled 125 m from the top of a hill to the bottom of a hill. How long
did it take for the ball to roll if the average velocity was 5m/s? *
Henry mixed salt and water together in a cup until he observed a clear solution. He measured the mass of the solution. Then he placed the cup outside for several sunny days during the summer. After a week, he observed that only solid salt remained in the cup and the mass had decreased. Henry concluded that a physical and chemical change occurred in this investigation.
Which statements correctly defend or dispute his conclusion?
He is correct. Dissolving salt in water is a physical change, but evaporating the water is a chemical change. Formation of a solid is evidence that a chemical change occurred.
He is correct. Evaporation is a physical change, but dissolving salt in water is a chemical change. The change in mass is evidence that a chemical change occurred.
He is incorrect. Dissolving salt in water and evaporation of the water are both physical changes. The reappearance of salt is evidence that the change was reversible by a physical change, so it could not be a chemical change.
He is incorrect. Dissolving salt in water and evaporation of the water are both chemical
Answer:
He is incorrect. Dissolving salt in water and evaporation of the water are both physical changes. The reappearance of salt is evidence that the change was reversible by a physical change, so it could not be a chemical change.
Answer:c
Explanation:
A hippopotamus laying on the rock exerts 10,000 N on the rock. The rock has a mass of
2 tons. How much work is being done? Be sure to show your work.
Answer:
Explanation:
If the hippo is laying on the rock, I'm assuming that there is no movement going on at all, in either the hippo or the rock. If no movement occurs, there is no work being done.
A 91.5 kg football player running
east at 2.73 m/s tackles a 63.5 kg
player running west at 3.09 m/s.
What is their velocity afterward?
Answer:
I'm pretty sure the velocity is 2.88 m/s
Explanation:
hope this is right good luck
Answer:
0.348
Explanation:
Acellus
what is unit of pressure?why is it called a derived unit ? give reasons
Answer:
Unit of pressure is pascal (Pa)
The SI-derived unit of measurement for pressure. The pascal is one newton (an SI-derived unit itself) per square meter.
True or False. Friction is a non-contact force?
( please answer !! i’ll mark brainliest! )
Answer:
False
Explanation:
Friction is a force exerted by a surface against the motion of a body across its surface. Therefore, friction is a type of contact force only.
Which of the motion variables is the same in both thex and y axis?
A) velocity
B) acceleration
C) time
D) displacement
Answer:
Acceleration (b) not sure tho
Explanation:
(v) A car
A car is pulled with a force of 60.N at angle of 30 ron, the
horizontal. Find the vertical and horizontal components of the applied
force.
Answer:
Explanation:
The vertical component is found in the magnitude of the force times the sine of the angle; the horizontal component is found in the magnitude of the force times the cosine of the angle. Thus:
vertical component = [tex]60.0sin(30.0)=30.0[/tex] and
horizontal component = [tex]60.0cos(30.0)=52.0[/tex]
A CAR APPROACHING A SCHOOL ZONE SLOWS DOWN FROM 38 M/S TO 10 M/S AT A CONSTANT ACCELERATION -4 METER PER SEC SQUARE HOW MUCH TIME IS REQUIRED TO SLOW DOWN TO FINAL VELOCITY
Answer:
7 seconds
Explanation:
he went down -28 m/s so 7 times -4 equals -28 m/s which is what he needed to slowness down to 10 m/s
A _____ is a model of an atom in which each dot represents a valence electron
Answer:
electron dot diagram is the answer to your question.
A body at rest or moving with uniform velocity will have acceleration equals
to:
A.
1
B.
0
C.
Negligible
D.
Infinity
Answer:
B:O
Explanation:
As acceleration is the rate of change of velocity with time, if velocity is uniform, there will be no change in it and acceleration will be zero.
