Answer:
24 m/s
Explanation:
Given that the height of the ball from the elevator, h=20 m
The acceleration due to gravity, g=10 m/[tex]s^2[/tex]
The initial velocity of the ball is zero, so, by using the equation of the motion [tex]v^2=u^2+2as[/tex] the velocity of the ball, v, when reached the elevator,
[tex]v^2=0+2\times 10 \times 20 \times h[/tex]
[tex]v=\sqrt{400}=20[/tex] m/s
The velocity of the ball just before the collision is 20 m/s in the downward direction.
The velocity of the lift just before the collision is 2 m/s in the upward direction.
As the ball and the lift moves in the opposite direction, so the speed of approach [tex]= 20+2=22[/tex] m/s.
Assuming that there is negligible change in the speed of the lift, so the velocity of the lift after the collision is 2 m/s
Let the velocity of the ball after the collision is [tex]V_2[/tex] m/s in the direction of the velocity of the lift.
So, the speed of the separation [tex]=V_2 -2[/tex]
As the collision is elastic, so the coefficient of restitution, [tex]\mu=1[/tex]
[tex]\mu = \frac {\text{Speed of seperation}}{\text{speed of approach}}[/tex]
[tex]\Rightarrow 1=\frac{V_2-2}{22} \\\\\Rightarrow V_2-2=22 \\\\\Rightarrow V_2=22+2 \\\\[/tex]
[tex]\Rightarrow V_2=24[/tex] m/s
Hence, the ball rebounds with a velocity of 24 m/s.
why we can not measure the total amount of heat energy that a body contains
Answer:
... As has been previously discussed, heat is not something that is contained in an object.
Explanation:
A double inclined plane that moves is a(n) .
Answer:
a wedge.
Explanation:
it moves when you apply force to one end of the wedge.
Convert 60000cm to m
Answer:
The answer is 600 using metric system
Answer:
600 cm
Explanation:
60,000 ÷100=600
Calculate the force used if 108J of work done is moving a wrapped present 9M
Answer:
F = 12 N
Explanation:
Mechanical Work
Mechanical work is the amount of energy transferred by a force. It's a scalar quantity, with SI units of joules.
Being F the force vector and s the displacement vector, the work is calculated as:
W = F.s
If both the force and displacement are parallel, then we can use the equivalent scalar formula:
W=F.s
When the value of the work is known and we need to find the force, we solve the above equation for F:
[tex]\displaystyle F=\frac{W}{s}[/tex]
The wrapping present is moved by s=9 m doing W=108 J of work. The force used is:
[tex]\displaystyle F=\frac{108}{9}[/tex]
F = 12 N
How much work is done in lifting a 300 Newton rock 10 meters off the ground?
Answer:
3000 JExplanation:
The work done by an object can be found by using the formula
workdone = force × distance
From the question we have
workdone = 300 × 10
We have the final answer as
3000 JHope this helps you
Which of these is not a method of preventing the corrosion of metals?
A) galvanising
B) painting
C) plating
D) rusting
Answer:
D
Explanation:
rusting is actually the corrosion of metals so it can't be a way to prevent itself.
You will measure and record the time it takes the cart to travel certain distances, and then complete some calculations. In the space below, write a scientific question that you will answer by doing this experiment.
Answer:
Take the measurement of the distance (d) with a meter rule (in meters) and also measure the time (t) of the travel in seconds with a stopwatch.
question: What is the speed of the cart?
Explanation:
The speed of an object in motion is the distance covered by the object with respect to time, that is, the ratio of distance covered to the time taken to reach that distance.
Speed = distance / time
= d (in meters m) / t (in seconds s) = m/s
What is the difference between the geographic North Pole and the magnetic north pole?
Answer:
Magnetic north is the direction towards the north magnetic pole, which is a wandering point where the Earth's magnetic field goes vertically down into the planet
Explanation:
I searched it up lol
The number of protons equals the atomic number. TRUE OR FALSE?
Answer:
true
Explanation:
The number of protons, neutrons, and electrons in an atom can be determined from a set of simple rules. The number of protons in the nucleus of the atom is equal to the atomic number (Z). The number of electrons in a neutral atom is equal to the number of protons.
3. A dog walks a distance of 100 ft. in 20 s of time. What is the dog's
speed in feet per second?
O C 120 ft/s
O B80 ft/s
O D 2000 ft/s
O A 5 ft/s
!!Help!!
A 1.5kg apple falls from a tree. If the apple falls for 2.75s before striking the ground, determine how far in meters the apple dropped before hitting the ground
Answer:
s = 37.81 m
Explanation:
Given that,
Mass of an apple, m = 1.5 kg
The apple falls for 2.75s before striking the ground.
We need to find how far the apple dropped before hitting the ground. It means we need to find the distance covered. Using the second equation of motion to find it :
[tex]s=ut+\dfrac{1}{2}gt^2[/tex]
u is initial velocity, u = 0 (at rest)
[tex]s=\dfrac{1}{2}gt^2\\\\s=\dfrac{1}{2}\times 10\times (2.75)^2\\\\=37.81\ m[/tex]
So, Apple dropped 37.81 m before hitting the ground.
Discuss the difference between short-term and long-term fitness goals. Provide an example of each
Answer:
The difference between a short-term and a long-term fitness goal is that short-term fitness goals are ones you could complete in a short period of time, a long term goal is something you'd work on for months or years.
An example of a short-term fitness goal: working out 2 times a week
An example of a long-term fitness goal: having a better diet or more lifestyle improvements
Electric current passing through a wire produces _.
a
a magnetic field around the wire
b
a compass
c
geographic poles
d
a permanent magnet
Answer: Answer is A.
A magnetic field around the wire
Explanation:
A component that is used to break a circuit is
(1 Point)
Wire
Switch
Bulb
Electric cell
Guys i need help please
Answer:
I'm pretty sure the answer is around 9.2 seconds
Explanation:
if the boy and his bike actually had a mass of 40 kg instead of 50 kg how much force would it take for him to accelerate at 0.8 m /s2
please help will give 15 points plus brainless
Answer:
F = 32 [N]
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.
∑F = m*a
where:
F = forces applied [N] (units of Newtons)
m = mass = 40 [kg]
a = acceleration = 0.8 [m/s²]
Now replacing:
[tex]F=m*a\\F = 40*0.8\\F = 32 [N][/tex]
A certain mass of a gas occupies 2 litres at 27 °C and 100
pascal. Find the temperature when volume and pressure
become half of their initial values.
pls give with solution pls pls
Answer:
75k
Explanation:
You can see solution in the picture
If you have a piece of brass and a piece of aluminurn that have the same volume, which will have a larger mass?
Answer:
the aluminum would have the most mass
A material has a low resistivity. Which statement is the best prediction about
this material?
A. It is a conductor that allows charge to move freely through it.
B. It is a conductor that does not allow charge to move freely through
it.
C. It it an insulator that does not allow charge to move freely through
D. It is an insulator that allows charge to move freely through it.
Please help fast
Answer:A
Explanation:I’m taking the test rn and I got it correct
It is a conductor that allows charge to move freely through it.
What is Resistivity?Resistivity is a distinctive attribute of any material that may be used to compare different materials based on how well they conduct electric currents. Low conductivity is indicated by high resistance.
The Greek letter rho is frequently used to represent resistance, which is numerically equivalent to the resistance R of a wire-like specimen, multiplied by its cross-sectional area A, and divided by its length.
The ohm is the measurement of resistance. The ratio of area in square meters to length in meters is reduced to merely meters in the metre-kilogram-second (mks) method.
Therefore, It is a conductor that allows charge to move freely through it.
To learn more about resistance, refer to the link:
https://brainly.com/question/29427458
#SPJ5
please help me asdrtyuio
Answer:
9. The Sun's Gravity
10. The core is the densest layer
HELP!
A position-time graph is shown below: (2 points)
Which statement accurately describes the speed of the object in the graph above over the four seconds?
O
Speed is increasing
Speed is constant.
Speed is decreasing.
Object is at rest.
Answer:
speed is increasing.
this is because the graph has a positive slope (due to it going up ), if it were decreasing, the graph would be going down
The speed of the object in the graph over the four seconds is increasing.
What is speed?Speed is distance travelled by an object in unit time. A distance-time graph, also known as a distance-travel graph, is a graph that shows how an object's distance changes over time.A speed-time graph, often known as a speed curve, is a graph that shows how an object's speed changes over time.
Examining the speed-time and distance-time graphs for an entity that is at rest when time is zero and does not change speed will be our first step. The ensuing figure given in the question.
Given that in the question the graph has a positive slope as the line in graph is going up , if it were decreasing, the graph would be going down from this we conclude that speed of the object in the graph over the four seconds is increasing.
To learn more about speed refer to the link:
brainly.com/question/28224010
#SPJ2
what is the acceleration of a 50kg object with 100 newtons force applied to it
In which case will an object float on a fluid? A) Buoyant force is greater than weight. B) Buoyant force is less than weight. C) Buoyant force equals weight. D) Buoyant force equals zero.
Answer:
The correct option is A
Explanation:
Buoyancy can be described as the upward force that causes an object to float on water. When the buoyant force of a liquid is greater than the weight of an object, the object will move to the surface of the liquid and float (because the buoyant force would be able to push it upwards). If the buoyant force is lesser than the weight of the object, the object will sink (because the buoyant force would not be able to push the object upwards). And when the buoyant force and weight of an object cancel out, the object would be suspended at the depth that this occurs.
Thus, from the explanation above, it can be deduced that for an object to float, buoyant force must be greater than weight of the object. Thus, the correct option is A.
An object will float on a fluid when the buoyant force acting on the object is equal to the weight of the object. This condition is described by option C: Buoyant force equals weight.
When an object is placed in a fluid, it experiences an upward force called the buoyant force. The buoyant force is a result of the pressure difference between the top and bottom surfaces of the object. It depends on the density of the fluid and the volume of the object submerged in the fluid.
For an object to float, the buoyant force must be equal to the weight of the object. If the buoyant force is greater than the weight, the object will experience a net upward force and will rise to the surface. In this case, the object will not remain floating, but rather float upwards.
If the buoyant force is less than the weight, the object will experience a net downward force and will sink in the fluid. The object will not float but instead submerge into the fluid.
Learn more about buoyant force here:
https://brainly.com/question/15706301
#SPJ11
Which one is an example of a force pushing downward toward the ground.
Group of answer choices
A man pulled weeds in his garden
A woman moved her child from one place to another in a wagon
A bird sat on a telephone wire
A dog tugged on a rope held by a child
Answer: A woman moved her child from one place to another in a wagon
or A bird sat on a telephone wire
Explanation:
21. A teacher does the following:
i. walks 4 m, south
ii. walks 8 m, east
iii. walks 4 m, north
iv. walks 8 m, west.
The overall displacement of the teacher is
a. Om
b. 6 m
c. 12 m
d. ... Nonsense! It cannot be calculated without knowing time information.
Answer:
displacement is the change from a starting point. she ends up back where she started so her displacement is zero meters although she traveled 24m in all.
an arrow is shot horizontally at a target 5 meters away with a velocity of 5 m/s. the target and bow are both 3 meters above the ground. will the arrow fall short, hit the target head on, or go above and past the target and by how much
Answer:
okk pls mark brainlist
HELP ASAP
The Target employees are working hard to get the orders out to everyone. The employees need to move packages from the ground level to the top of the loading dock platform. As shown in Figure 1, the employee pushes the package up a ramp (you may assume friction is negligible). In figure 2, the employee lifts the package straight up from ground to the loading dock platform. In which case does the employee do more work on the box and why?
a
Lifting the box straight up, because the incline acts as a simple machine and reduces the force required
b
Lifting the box straight up, because it requires a larger applied force to lift it straight up
c
Pushing the box up the incline, because the force is applied for a longer distance
d
Neither method, because the work is the same in both cases, since using the ramp decreases the force by the same factor that it increases the distance
Answer:
I believe the answer is B
A 20 kg crate initially at rest on a horizontal floor requires a 80 N horizontal force to set it in motion. Find the coefficient of static friction between the crate and the floor.
Answer:
The coefficient of static friction between the crate and the floor is 0.41
Explanation:
Friction Force
When an object is moving and encounters friction in the air or rough surfaces, it loses acceleration and velocity because the friction force opposes motion.
The friction force when an object is moving on a horizontal surface is calculated by:
[tex]Fr=\mu N[/tex] [1]
Where [tex]\mu[/tex] is the coefficient of static or kinetics friction and N is the normal force.
If no forces other then the weight and the normal are acting upon the y-direction, then the weight and the normal are equal in magnitude:
N = W = m.g
The crate of m=20 Kg has a weight of:
W = 20*9.8
W = 196 N
The normal force is also N=196 N
We can find the coefficient of static friction by solving [1] for [tex]\mu[/tex]:
[tex]\displaystyle \mu=\frac{Fr}{N}[/tex]
The friction force is equal to the minimum force required to start moving the object on the floor, thus Fr=80 N and:
[tex]\displaystyle \mu=\frac{80}{196}[/tex]
[tex]\mu=0.41[/tex]
The coefficient of static friction between the crate and the floor is 0.41
A roller coaster travels down a 120 m track in 12.5 seconds how fast does the roller coaster go
Answer:
9.6m/s
Explanation:
Using the equation S=d/t where s=speed, d=distance, and t=time
plug in the known variables
S=120m/12.5s
S=9.6m/s
_______________ is the name for the permanent destruction and clearing of forests
Answer:
DeforestationExplanation:
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According to Vocal Media,
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Deforestation is the permanent destruction of forests in order to utilize the land or trees. Typically, deforestation is clearing a lot of trees without the intention of establishing future growth. Harvesting, forest fires, and insect infestations do not count as deforestation because the affected areas will eventually grow back.
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Hope this helps! <3
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