Explanation:
By Hooke's Law, Fe = kx.
Since Fe = 1.6N and x = 9.2cm - 8cm = 1.2cm,
k = Fe/x = 1.6N/1.2cm = 1.33N/cm.
An astronaut floating at rest in space throws a wrench in one direction and subsequently recoils back with a velocity in the opposite direction. Which of the following statements is/are true?
I. The velocity of the wrench is equal and opposite to the velocity of the astronaut.
Il. The momentum of the wrench is equal and opposite to the momentum of the astronaut.
III. The impulse applied to the wrench is equal and opposite to the impulse applied to the astronaut
a) ll and ill only
b) I only II only
c) I, II, and III
d) I and Il only
Answer:
a) ll and Ill only
Explanation:
Let the mass of the wrench = m
and the mass of the astronaut = M
Initially, the velocity of the astronaut and wrench are zero.
The astronaut throws the wrench in one direction and subsequently recoils back with a velocity in the opposite direction.
Let v and V be the velocity of the wrench and the velocity of the astronaut respectively.
In space, there is no external force acting, the momentum must be conserved.
So, m(0)+M(0)=m(v)+M(V)
So, 0=mv+MV
[tex]\Rightarrow mv=-MV[/tex] ...(i)
Here, the momentum of the wrench = mv, and the momentum of the astronaut= MV. The negative sign showing that both the momentum are in opposite direction.
Therefore, the momentum of the wrench is equal and opposite to the momentum of the astronaut.
According to Newton's second law, the rate of change of momentum = applied force.
Let it take [tex]\Delta t[/tex] seconds to change the momentum.
So, for the wrench
[tex]m(v-0)/\Delta t= F_w \\\\\Rightarrow m(v-0)=F_w\Delta t \\\\\Rightarrow mv=F_w\Delta t \cdots(ii)[/tex]
Here, [tex]F_w\Delta t[/tex] is the impulse applied to the wrench.
Similarly, for the astronaut
[tex]M(-V-0)/\Delta t= F_a[/tex] [negative sign (-V) for opposite direction]
[tex]\Rightarrow M(-V-0)=F_a\Delta t \\\\\Rightarrow -MV=F_a\Delta t[/tex]
Here, [tex]F_a\Delta t[/tex] is the impulse applied to the astronaut.
So, the impulse on the astronaut.
By using equations (i) and (ii)
[tex]F_a\Delta t=F_w\Delta t[/tex]
Therefore, the impulse applied to the wrench is equal and opposite to the impulse applied to the astronaut.
Hence, option (a) is correct.
Joe applies a force of 50 N to a box which has a mass of 15 kg. What is the acceleration of the box?
a.
Answer:
3.333 m/s^2
Explanation:
50/15 = 3.33 m/s^2
A Ferris wheel with 60 spokes has a diameter of 100 m. It makes one rotation every 60 seconds. Find the speed of the passengers when the Ferris wheel is rotating at this rate.
Answer:
The speed of the passengers is 5.24 m/s
Explanation:
Uniform Circular Motion
It occurs when an object in a circular path travels equal angles in equal times.
The angular speed can be calculated in two different ways:
[tex]\displaystyle \omega=\frac{v}{r}[/tex]
Where:
v = tangential speed
r = radius of the circle described by the rotating object
Also:
[tex]\omega=2\pi f[/tex]
Where:
f = frequency
Since the frequency is calculated when the number of revolutions n and the time t are known:
[tex]\displaystyle f=\frac{n}{t}[/tex]
The Ferris wheel has a diameter of 100 m and makes n=1 rotation in t=60 seconds, thus the frequency is:
[tex]\displaystyle f=\frac{1}{60}\ Hz[/tex]
The angular speed is:
[tex]\displaystyle \omega=2\pi \frac{1}{60} =\frac{\pi}{30} \ rad/s[/tex]
Now we calculate the tangential speed, solving this formula for v:
[tex]\displaystyle \omega=\frac{v}{r}[/tex]
[tex]v=\omega . r[/tex]
The radius is half the diameter, r=100/2=50 m:
[tex]\displaystyle v=\frac{\pi}{30} . 50[/tex]
Calculating:
v = 5.24 m/s
The speed of the passengers is 5.24 m/s
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 = (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=\frac{W}{t}[/tex]
where:
P = power [W] (units of watts)
W = work [J]
t = time = 40 [s]
[tex]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]
name three characteristics of sound
1. If a 4000 kg rocket reaches 7,000 m/s in 8 minutes after blastoff, what is its acceleration?
2. What force is being applied to the rocket?
3. What is the rocket's potential energy when it is 12 km off the ground?
(Hint - Change kilometers to meters)
4. If the rocket were to fall from the 12 km height, what would be its speed right before hitting the ground? (assume no air resistance)
+ answer all the questions plz
Answer:
I guess the Ans for second one is gravitational force
If forces acting on an object are unbalanced, the object could experience a change in ________.
mass, speed, or direction
negative acceleration or mass
direction, mass, or both
speed, direction, or both
D) Speed, direction, or both
Mass doesn’t just CHANGE like that.
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
A 300 g bird flying along at 6.0 m/s sees a 10 g insect heading straight toward it with a speed of 30 m/s. the bird opens its mouth wide and enjoys a nice lunch. What is the bird's speed immediately after swallowing?
Answer:
6.77m/s
Explanation:
Using the law of conservation of momentum
m1u1 + m2u2 = (m1+m2)v
m1 and m2 are the masses of the object
u1 and u2 are the velocities before collision
v is the final collision
Given
m1 = 300g = 0.3kg
u1 = 6.0m/s
m2 = 10g = 0.01kg
u2 = 30m/s
Required
The bird's speed immediately after swallowing v
Substitute the given values into the formula
m1u1 + m2u2 = (m1+m2)v
0.3(6) + 0.01(30) = (0.3+0.01)v
1.8+0.3 = 0.31v
2.1 = 0.31v
v = 2.1/0.31
v = 6.77m/s
Hence the bird's speed immediately after swallowing is 6.77m/s
Need help ASAP plsss
Write 5-6 sentences about
:how do parachutes work ??
A ripcord system pulls a closing pin, which releases a spring-loaded pilot chute, and opens the container; from which the parachute comes out.
If a skydiver is unable to open her/his parachute, an automatic activation device will automatically open the parachute.
A parachute works by forcing air into the front of it and creating a structured 'wing' under which the canopy pilot can fly. Parachutes are controlled by pulling down on steering lines which change the shape of the wing, cause it to turn, or to increase or decrease its rate of descent.
Select the correct answer.
Derick has been working as a first responder since many years. His primary responsibility at a crime scene is to question witnesses and gather
useful information from the scene. Which of these first responder career roles does Derick fit into?
OA paramedic
OB. police officer
Oc. fire truck driver
OD. firefighter
Answer:
Police officer
Explanation:
Because police officers wants to gather information on what happens and question people to know everything. That is what Derick is doing
A truck is traveling at 27 m/s down the interstate highway where you are changing a flat tire. frequency of 185 Hz.
A) What frequency do you hear?
B) Suppose after fixing the flat you were driving your car at 22 m/s the truck drives blows his horn again. What frequency do you hear? (Speed of sound in air is 340 mis).
Answer:
(a) the observed frequency is 200 Hz
(b) the observed frequency is 188 Hz.
Explanation:
speed of the truck, Vs = 27 m/s
frequency of the truck as it approaches, Fs = 185 Hz
(a) Apply Doppler effect to determine the frequency you will hear.
As the truck approaches you, the observed frequency will be higher than the source frequency because of decrease in distance.
[tex]F_s = F_o [\frac{V}{V_S + V} ][/tex]
Where;
Fo is the observed frequency which is the frequency you will hear.
V is speed of sound in air
[tex]F_s = F_o [\frac{V}{V_S + V} ]\\\\185 = F_o [\frac{340}{27 + 340} ]\\\\185 = F_o (0.926)\\\\F_o = \frac{185}{0.926}\\\\F_o = 199.78 \ Hz[/tex]
[tex]F_o = 200 \ Hz[/tex]
(b) Apply the following formula for a moving observer and a moving source;
[tex]F_o = F_s[\frac{V-V_o}{V} ](\frac{V}{V-V_S} )[/tex]
The observed frequency is negative since you are driving away from the truck and the source frequency is also negative since it is driving towards you.
[tex]F_o = F_s[\frac{V-V_o}{V} ](\frac{V}{V-V_S} )\\\\F_o = 185[\frac{340-22}{340} ](\frac{340}{340-27} )\\\\F_o = 185(0.9353)(1.0863)\\\\F_o = 188 \ Hz[/tex]
What kind of electricity does turning wheel generates? Please help!
Answer: Kinetic Energy to Electrical.
Explanation: The magnet is rotated as a result of the spinning wheels, and this results in a powerful stream of electrons, therefore converting kinetic to electrical.
how is solar impulse is different than conventional airplane
Answer:
Solar Impulse is a Swiss long-range experimental solar-powered aircraft project and Conventional Aircraft are the atmosphere-only aircraft that have been around since the Wright Flyer's first takeoff. Though modern craft are much more advanced and capable than that early model, Conventional Aircraft have been superseded in modern times by the AeroSpace Fighter, which can operate in both atmosphere and space.
Explanation:
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.
Use the image below to answer the question.
What does the arrow 'B' represent?
Question 7 options:
wavelength
refraction
frequency
compression
A ball of mass 4kg moving with a velocity of 20m/s collides with another ball of mass 15kg moving with a velocity of 15m/s in the same direction. Calculate the velocity of the 5kg ball if the collision is perfectly inelastic.
Answer:
velocity = 16.05 m/s
Explanation:
inelastic collision formula:
m1u1 + m2u2 = (m1 + m2)v
m1 = 4kg
u1 = 20m/s
m2 = 15kg
u2 = 15m/s
find v ?
m1u1 + m2u2 = (m1 + m2)v
(4×20) + (15×15) = (4+15)v
80 + 225 = 19v
305 = 19v
19v = 305
v = 305/19
v = 16.05 m/s
Pelican hunts fish in the water as th pelican the waters surface why must it aim for the fish in a slightly different place than where the fish appears to be located
The Pelican must aim differently than where the fish appears to be because light is refracted from air to water.
Refraction is the change in the direction of a wave at the interface between two media. The effects of refraction are easily seen when light is travelling from air to water hence objects are not really where they appear to be when viewed above the water surface.
Hence, the Pelican must aim differently than where the fish appears to be because light is refracted from air to water.
Learn more about refraction: https://brainly.com/question/11155928
True/False: The Earth's core is completely solid, and the only liquid portion of the Earth's layers is the crust.
Answer:
true i believe
Explanation:
Answer:
true
Explanation:
true because other guy said it lol
What are some ways that the Greeks demonstrated their passion for public life?
Answer:
The Greeks had drama and arts competitions that were considered very popular, and important in society.
Explanation:
hope it helps!
what is the difference between alcoholic and Mercury thermometer based on their function?
The rate of change of velocity or speed is known as acceleration. If a car increases it speed form 10 to 20m/s in 2 seconds, then what is its rate of change in velocity?
A) 5 m/s/s
B) 10 m/s/s
C) 20 m/s/s
D) 40 m/s/s
Answer:
A) 5 m/s/s
Explanation:
Given the following data;
Initial velocity = 10m/s²
Final velocity = 20m/s²
Time, t = 2 seconds.
In physics, acceleration can be defined as the rate of change of the velocity of an object with respect to time.
This simply means that, acceleration is given by the subtraction of initial velocity from the final velocity all over time.
Hence, if we subtract the initial velocity from the final velocity and divide that by the time, we can calculate an object’s acceleration.
Mathematically, acceleration is given by the equation;
[tex]Acceleration, a = \frac{final \; velocity - initial \; velocity}{time}[/tex]
Substituting into the equation, we have;
[tex]Acceleration, a = \frac{20 - 10}{2}[/tex]
[tex]Acceleration, a = \frac{10}{2}[/tex]
Acceleration, a = 5m/s²
Which of the following is an opinion about friction?
It always acts in the opposite direction as the motion of the object.
It stops objects on Earth from staying in motion forever.
It slows objects down too much.
It happens any time two objects are in contact.
Help me out please-
You'll get 40 points
My opinion about friction is that It always acts in the opposite direction as the motion of the object.
What is friction?Friction refers to the resistance of motion of one object that is moving relative to another object. Fricton has many application but it has also many disadvantages.
So we can conclude that friction is always acts in the opposite direction as the motion of the object.
Learn more about friction here: https://brainly.com/question/24338873
What is unique regarding the abdominal muscle when is compared to other muscle in the body?
(A) it is a very large muscle
(B) it does not develop easily
(C) it can move the body either from the ribcage or the pelvis.
(D) it can get injured easily if you perform a lot os repetitions.
(E) none of the above
SOMEBODY ONCE TOLD ME THE WORLD WAS GONNA ROLL ME
I AIN'T THE SHARPEST TOOL IN THE SHED~
SHE WAS LOOKING KINDA DUM WITH HER FINGER AND HER THUMB
IN THE SHAPE OF AN "L" ON HER FOREHEAD~
WELL THE YEARS START COMING AND THEY DON'T STOP COMING
FED TO THE RULES AND I HIT THE GROUND RUNNING
DIDN'T MAKE SENSE NOT TO LIVE FOR FUN
YOUR BRAIN GETS SMART BUT YOUR HEAD GETS DUM
SO MUCH TO DO, SO MUCH TO SEE--
SO WHATS WRONG WITH TAKING THE BACKSTREETS?
YOU'LL NEVER KNOW IF YOU DON'T GO
YOU'LL NEVER SHINE IF YOU DON'T GLOW.
Answer:
so true though
Explanation:
What is the force (in Newtons, 1 Newton = 1Kgm/s2) required to accelerate a 1500 Kg car to 3 m/s2?
Answer:
F=4500N
Explanation:
F=m×g
F=1500kg×3m/s²
F=4500N
Answer:
F=4500N
Explanation:
F=m×g
F=1500kg×3m/s²
F=4500N
Do YOU think aliens are real? HELP PLS
Which answer best displays Adam's use of the civic virtue "diversity"?
Diversity means something is benifical to an entire group.
Diversity means fair treatment of all people the
Answer:Yes
Explanation:yeah i think it could be possible because the universe is so far and wide its probably infinite and if we did i personally believe that we would be absolutely be annihilated by them because we would be so far behind technology wise we would have no use for the\
YOU FELL FOR IT FOOL THUNDER CROSS SPLIT ATTACK
1. A girl drops a ball off the roof of her house. It takes the ball 2 seconds to hit the ground. How tall
is the house?
If the acceleration constant..
you can use the formula s = ut + 1/2at²
Known that :
s = ?
u = 0
t = 2s
a = 10ms-²
Then you can apply the formula
s = ut + 1/2at²
s = 0 + 1/2(10)(2)²
s = 5 × 4
s = 20m
Answer : 20m
Explanation :
The gravity can be 9,8 or 10. Also im not sure how people teach you but in my school, if the ball goes down the gravity is positive and not negative thats why i put 10ms-² and not -10ms-²
s = displacement/distance
u = initial speed
a = acceleration
t = time
sorry if im wrong
Which wave has a greater frequency
Answer:
A I think
Explanation:
because what is the most frequency a because it has more frequency I think I'm not that sure
help plz i need it in the next 30 mins
Answer:
i think it's d
Explanation:
Answer:
D
Explanation:
i feel like this one is it