Answer:
A stunt person jumps from the roof of a tall building, but no injury occurs because the person lands on a large, air-filled bag. Which one of the following best describes why no injury occurs?
The bag increases the amount of time during which the momentum is changing and reduces the average force on the person.
ANSWER: A
Answer:
A. The bag increases the amount of time during which the momentum is changing and reduces the average force on the person.
During stunts, people usually put an-air filled bag on the ground for safe landing and to prevent injuries.
Momentum is calculated by m* v where m is for mass and v is for velocity.
Force is directly proportional to momentum
F∝M
The bag in this scenario helps to increases the amount of time the force acts on the person. This implication means that there is a reduction in the change of momentum. Since Force and momentum have a directly proportional relationship then the Force taken to hit the floor is greatly reduced.
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A child of mass m is at the edge of a merry-go-round of diameter d. When the merry-go-round is rotating with angular acceleration α, the torque on the child is τ. The child moves to a position half way between the center and edge of the merry-go-round, and the angular acceleration increases to 2α. The torque on the child is now
Answer:
The torque on the child is now the same, τ.
Explanation:
It can be showed that the external torque applied by a net force on a rigid body, is equal to the product of the moment of inertia of the body with respect to the axis of rotation, times the angular acceleration.In this case, as the movement of the child doesn't create an external torque, the torque must remain the same.The moment of inertia is the sum of the moment of inertia of the merry-go-round (the same that for a solid disk) plus the product of the mass of the child times the square of the distance to the center.When the child is standing at the edge of the merry-go-round, the moment of inertia is as follows:[tex]I_{to} = I_{d} + m*r^{2} = m*\frac{r^{2}}{2} + m*r^{2} = \frac{3}{2}* m*r^{2} (1)[/tex]
So, τ = 3/2*m*r²*α (2)When the child moves to a position half way between the center and the edge of the merry-go-round, the moment of inertia of the child decreases, as the distance to the center is less than before, as follows:[tex]I_{t} = I_{d} + m*\frac{r^{2}}{4} = m*\frac{r^{2}}{2} + m*\frac{r^{2}}{4} = \frac{3}{4}* m*r^{2} (3)[/tex]
Since the angular acceleration increases from α to 2*α, we can write the torque expression as follows:τ = 3/4*m*r² * (2α) = 3/2*m*r²
same result than in (2), so the torque remains the same.
What's a Weber?
in electromagnetism
Answer:
In physics, the weber is the SI derived unit of magnetic flux. A flux density of one Wb/m2 (one weber per square metre) is one tesla.
Hope it helps !
Answer:
Weber unit of magnetic flux in the international system of units (SI), defined as the amount flux that, linking an electrical circuit of one turn (one loop of wire) , produces in it an electromotive force of one volt as the flux is reduced to zero as a uniform rate in one second .
it was named in honour of the 19th century German physicist Wilhelm Eduard Weber
Based on its location on the periodic table, which metal is likely to be less reactive than both strontium and sodium?
magnesium (Mg)
barium (Ba)
cesium (Cs)
rubidium (Rb)
Answer:
Magnesium is the correct answer
Explanation:
It is magnesium because as we move down the periodic table group, atomic sizes increase which is as a result of lesser forces of attraction between nucleus and valence of an atom which makes the atom to be prone to leave as electrons so easily, elements become more reactive.
But as we move along the period , atomic sizes decrease because there is a more force of attraction between nucleus of an atom and it valence electrons making it less reactive just as the case in magnesium. Other elements are more reactive than it across the group.
Answer:
Magnesium
Explanation: Correct on edge!
Hope this Helps! :)
A car is moving at 25.5 m/s when it accelerates at 1.94 m/s^2 for 2.3 s. What is the car's final speed? (Keep in mind direction and round to 2 decimals)
Answer:
29.96m/s
Explanation:
Given parameters:
Initial speed = 25.5m/s
Acceleration = 1.94m/s²
Time = 2.3s
Unknown:
Final speed of the car = ?
Solution:
To solve this problem, we are going to apply the right motion equation:
v = u + at
v is the final speed
u is the initial speed
a is the acceleration
t is the time taken
Now insert the parameters and solve;
v = 25.5 + (1.94 x 2.3) = 29.96m/s
Give reason:
a) In 'coin on card' experiment a smooth card is used.
Answer:
Please mark as brainliest!!
Explanation:
In coin card experiment smooth card is used so that the card can slide easily from glass.
Answer:
In coin card experiment smooth card is used so that the card can slide easily from glass.
The reason why you should always exercise your abdominal during an exercise session is :
(A) because you will be fully warmed up
(B) you can focus on this muscle better
(C) because is the abdominal muscle is needed in all exercises during a workout
(D) because most people do it that way
(E) it does not really matter if you exercise the abdominal first or last
an electric iron draws a current of 5a when connected to a 250v supply. calculate the energy used buy the iron if it's used for 10 minutes
Answer:
The energy used by the iron is 0.2083 KWH.
Explanation:
Electric Energy
The energy consumed by an electrical appliance is given by:
E = P.t
Where:
P = Power consumed
t = Time the appliance is connected to the power supply
The power can be calculated as a function of the voltage V and the current I:
P = V.I
Therefore, the energy is:
E = V.I.t
The electric iron draws a current of I=5 A when connected to a V=250 V supply for t=10 minutes. The time must be expressed in hours, thus t=10/60=0.167 hours.
Thus, the energy is:
E = 250 V * 5 A * 0.167 H
E = 208.33 WH
Converting to KWH:
E = 208.33/1000 = 0.2083 KWH
The energy used by the iron is 0.2083 KWH
Why when i take "The FitnessGram Pacer Test is a multistage aerobic capacity test that progressively gets more difficult as it continues. The 20 meter pacer test will begin in 30 seconds. Line up at the start. The running speed starts slowly, but gets faster each minute after you hear this signal. A single lap should be completed each time you hear this sound. Remember to run in a straight line, and run as long as possible." i don't fall flat on my face?
Answer:
NOOOOOOO NOT THE PACER TEST!!
Explanation:
MEMORIES OF MIDDLE SCHOOL I'D LIKE TO FORGET
also. LOL "Remember to run in a straight line" BRUH WE KNOW XDXD
Multiply.
(2x + 4)(x - 4)
Answer:
(2x + 4)(x - 4)=2x^2-4x-16
what type of plate boundary decreases the amount of the Earth's crust?
Answer:
Convergent.
Explanation:
Just as oceanic crust is formed at mid-ocean ridges, it is destroyed in subduction zones. Subduction is the important geologic process in which a tectonic plate made of dense lithospheric material melts or falls below a plate made of less-dense lithosphere at a convergent plate boundary.
A herdsman yelling out to a fellow herdsman heard his voice reflected by a cliff 4s later.What is
the velocity of sound in air if the cliff is 680m away
Answer:
v = 340 m/s
Explanation:
Given that,
A herdsman yelling out to a fellow herdsman heard his voice reflected by a cliff 4s later.
The cliff is 680 m away
We need to find the velocity of sound in air.
Velocity = distance/time
Distance = 2 × 680 = 1360 m
[tex]v=\dfrac{1360\ m}{4\ s}\\\\=340\ m/s[/tex]
So, the velocity of sound in air is 340 m/s.
The image shows a diagram explaining a concept.
Which concept does the diagram show?
A. tempature
B. Altitude
C. air density
D. air pressure
Answer:
D.
Explanation
Air pressure.
Answer:air pressure
Explanation:
Objects in free fall are weightless.
Please select the best answer from the choices provided
T
F
Answer:
[tex]\boxed{True}[/tex]
Explanation:
Objects are weightless in free fall because their is no other force pushing them rather than the gravitational force.
Hope it helps!<3
Answer:
It's ture hope this answer help have a great day .!Explanation:
Ishan is testing materials to see whether they will stick to a magnet. How can
he use his imagination in this experiment?
OA. To think of different materials to test
OB. To carefully record the results in a chart
O C. To do the test the same way each time
O D. To remember which materials are magnetic
Answer:
The Answer is A "To think of different materials to test"
Explanation:
APE X
(kg)
The table shows the relationship between the masses of two objects, the distance between the
two objects, and the gravitational force between the objects
Mass
of Object 1 Mass of Object 2 Distance between Gravitational
(kg)
Objects 1 and 2 Force between
(m)
Objects 1 and 2
(N)
1
16
2G
2
1 G
3
3
9 G
9
3
3
3G
1
2
1
6. Which conclusion is supported by the data in the table? (1 point)
An increase in the mass of an object causes the same decrease in the gravitational force
An increase in the distance between the objects causes the same decrease in the gravitational force
An increase in the distance between the objects causes a greater change in the gravitational force than the same increase in mass.
An increase in the mass causes a greater change in the gravitational force than the same increase in the distance between the objects
Answer:
(C) an increase in tue distance between the ibject causes a greater change in the gravitational force than the same increase in mass
Hope this helps
Answer:
C: An increase in the distance between the objects causes a greater change in the gravitational force than the same increase in mass.
Explanation:
it's C on edge! hope this helps!!~ (❁´▽`❁)*✲ﾟ*
A person pushing a bin with 45 N of force slides the 3 kg plastic bin on a rough surface with friction. The plastic bin is moving with a constant velocity. What is the net force acting on the box?
Answer:
F = 0
Explanation:
Given that,
Force acting to push a bin = 45 N
Mass of the plastic bin, m = 3 kg
The plastic bin is moving with a constant velocity.
We need to find the net force acting on the box. Constant velocity means the change in velocity is equal to 0. It means acceleration will be 0.
As a result, the force acting on the box is equal to 0.
A ball weighing 60 N is swinging like a pendulum at the end of a 6.0 m rope. As the ball swings through its lowest point, its speed is measured at 5.0 m/s. What is the tension in the rope at this point?
A. 58.6 N
B. 85.4 N
C. 90.2 N
D. 97.3 N
Answer:
B. 85.4 N
Explanation:
The tension in the rope at the lowest point of the motion of the ball is antiparallel to the weight of the ball. By Newton's laws we construct the following equation of equilibrium:
[tex]\Sigma F = T - W = \left(\frac{W}{g} \right)\cdot \frac{v^{2}}{L}[/tex] (1)
Where:
[tex]T[/tex] - Tension in the rope, measured in newtons.
[tex]W[/tex] - Weight, measured in newtons.
[tex]g[/tex] - Gravitational acceleration, measured in meters per square second.
[tex]v[/tex] - Speed of the ball, measured in meters per second.
[tex]L[/tex] - Length of the rope, measured in meters.
If we know that [tex]W = 60\,N[/tex], [tex]g = 9.807\,\frac{m}{s^{2}}[/tex], [tex]v = 5\,\frac{m}{s}[/tex] and [tex]L = 6\,m[/tex], then the tension in the rope at this point is:
[tex]T = W+\frac{W\cdot v^{2}}{g\cdot L}[/tex]
[tex]T = W\cdot \left(1+\frac{v^{2}}{g\cdot L} \right)[/tex]
[tex]T = (60\,N)\cdot \left[1+\frac{\left(5\,\frac{m}{s} \right)^{2}}{\left(9.807\,\frac{m}{s^{2}} \right)\cdot (6\,m)} \right][/tex]
[tex]T = 85.492\,N[/tex]
Hence, the correct answer is B.
the surface of objects in contact are not completely smooth true or false
Answer:
true objects in contact are not completely smooth
A ray moving in water at 55.5 deg
enters plastic, where it bends to
48.7 deg. What is the index of
refraction for the plastic?
( water n = 1.33, Air n = 1.00 )
Answer:
Refractive index of the plastic = 1.46
Explanation:
By Snell's law,
[tex]\frac{\text{sin}\theta _{2} }{\text{sin}\theta _{1}}=\frac{n_1}{n_2}[/tex]
Here, [tex]\theta _1[/tex] = Angle of incidence in medium 1 (Plastic)
[tex]\theta_2[/tex] = Angle of refraction in medium 2 (Water)
[tex]n_1[/tex] = Refractive index of medium 1 (Plastic)
[tex]n_2[/tex] = Refractive index of medium 2 (Water)
By substituting values in the formula,
[tex]\frac{\text{sin}(48.7)}{\text{sin}(55.5)}=\frac{1.33}{n_2}[/tex]
[tex]n_2=\frac{1.33\times \text{sin}(55.5)}{\text{sin}(48.7)}[/tex]
= 1.46
Therefore, refractive index of the plastic = 1.46
A box of weighing 60N is placed on the ground. The bottom of the box measures 2m by 1m. What is the pressure on the ground? *
Answer:
pressure=force/area
p=60N/(2m×1m)
=35N/M
identical spheres are dropped from a height of 100 m above the surfaces of Planet X and Planet Y. The speed of the spheres as a function of time is recorded for each planet in the graph
above. Which planet exerts the greater force of gravity on the sphere, and what evidence supports this conclusion?
A Planet X because its line has the greater area under it.
Planet X, because its line has the greater slope
Planet Y. because it falls for the smaller amount of time
Planet Y because the object's final speed is greater
Answer:
B. Planet X, because its line has the greater slope.
Explanation:
In a speed graph, acceleration is slope. A greater slope means a greater acceleration. According to Newton's 2nd law (F=mg), a greater acceleration means a greater force.
Planet X exerts the greater force of gravity on the sphere, because its line has the greater slope. Hence option B is correct.
What is Gravitational Force ?Gravitational force is force of attraction between two masses. Gravitational force(F) between two bodies is directly proportion to the product of masses(m₁,m₂) of two bodies and inversely proportional to square of distance(r) between them. mathematically it is written as,
F ∝ m₁.m₂
F ∝ 1/r²
F = G m₁,m₂÷r²
where G is gravitational constant, whose value is 6.6743 × 10⁻¹¹ m³ kg-1s⁻².
Force is expressed in Newton N in SI unit. its dimensions are [M¹L¹T⁻²].
This is analogous with coulomb's law which gives force between two charges.
if a planet has greater gravitational force(force of gravity), then body falls with greater speed as compare to other planet which is having less force of gravity. we can see in case of planet X there is greater speed as compare to plane Y in short time. Hence option B is correct.
To know more about Gravity :
https://brainly.com/question/31321801
#SPJ2.
what are the very small particles that make up matter
Answer:
The very small particles that make up matter are I) Atoms
Matter - Anything that have mass and occupies space is called matter . it is made up of atoms and molecules
Atoms - The smallest part of matter is called atom.
Molecule - Group of atoms combine together to form a molecule.
More to know - Atom is made up of even smaller particles called neutron, proton and electron. Electron moves around nucleus ( nucleus is made up of neutron and proton) Different types of atom combine and form molecule ( Nitrogen dioxide No2 has 1 atom of nitrogen and 2 atoms of oxygen)Need help ASAP plz and thank you!!
Answer: Possibly b
Explanation:
a machine
of efficiency of 70% is used to raise
a body of
mass 80 kg through
a vertical distance of 3m in
40 seconds. Calculate the power input. (Take g = 10 m/s²)
Answer:
Power_input = 85.71 [W]
Explanation:
To be able to solve this problem we must first find the work done. Work is defined as the product of force by distance.
[tex]W =F*d[/tex]
where:
W = work [J] (units of Joules)
F = force [N] (units of Newton)
d = distance [m]
We need to bear in mind that the force can be calculated by multiplying the mass by the gravity acceleration.
Now replacing:
[tex]W=m*g*d[/tex]
[tex]W=80*10*3\\W=2400[J][/tex]
Power is defined as the work done over a certain time. In this way by means of the following formula, we can calculate the required power.
[tex]P=W/t[/tex]
where:
P = power [W] (units of watts)
W = work [J]
t = time = 40 [s]
[tex]P=W/t\\P=2400/40\\P=60 [W][/tex]
The calculated power is the required power. Now as we have the efficiency of the machine, we can calculate the power that is introduced, to be able to do that work.
[tex]Effic=0.7\\Effic=P_{required}/P_{introduced}\\P_{introduced}= 60/0.7\\P_{introduced}=85.71[W][/tex]
How long( in hours, will it take for 500 000 C of charge to flow through a diode if it requires
0.05 Amp to operate it.
Answer:
277.78 hours
Explanation:
The formula for calculating the amount of charge is expressed as;
Q = It
I is the current
t is the time
Given
I =0.05A
Q = 50,000C
Required
Time t
Recall that: Q = It
t = Q/I
t = 50,000/0.05
t = 1,000,000secs
Convert to hours
1,000,000secs = 1,000,000/3600
1,000,000secs = 277.78 hours
Hence it will take 277.78 hours for the charge to flow through the diode
If the body is at rest while I am pushing it with a force of 20 Newtons and the force of static friction is 20 Newtons, will it move or should I push with a force greater than 20
Answer:
It will not move, so you should push with a force greater than 20 N.
Explanation:
Static friction is a force that keeps a body at rest. This means static friction will be the force that keeps the body from moving when there is no push or pull hence you should overcome it with enough opposing force for the body to move.
In this case for the body to move , you should push with a force greater than 20 N for it to move.
which is NOT true of the Big Bang Theory?
1. it explains what’s happening in the universe now
2. it explains what caused the big bang.
3. it explains what the universe was like in the beginning
4. it stages that the universe is expanding
Answer:
1. it explains what's happening im the universe now
The wavelength of a water wave is 54 m. It has a frequency of 0.03 Hz. What is the velocity of the wave?
Answer:
1.62 m/s
Explanation:
Wavelength of the water wave= 54 m
The frequency is 0.03 Hz
Therefore the velocity can be calculated as follows
Velocity= frequency × wavelength
= 0.03 × 54
= 1.62 m/s
two spheres A and B are projected off the edge of a 1.0 m high table with the same horizontal velocity . sphere A has a mass of 20.g and sphere B has a mass of 10.g.
If both spheres leave the edge of the table at the same instant, sphere A will land
a. at some time after sphere B.
b. at the same time as sphere B.
c. at some time before sphere B.
d. There is not enough information to decide.
Answer:
A lands first becuase its heavier
What is meant by the statement,the linear expansivity of copper is 0.000017k
Answer:
The change in length per unit length per degree rise in temperature of copper is 0.000017k
Explanation:
Given that :
The linear expansivity of copper is 0.000017k. This simply means that ; for a given copper length, the length of such copper will increase by 0.000017k for every degree rose in temperature of the copper rod.
Therefore, the change in length per unit length per degree rise in temperature (k) is 0.000017