A ball is thrown straight up from the ground with an unknown velocity. It returns to the ground after 4.0 s. With what velocity did it leave the ground?
Answer:
It must return at the same velocity with which it was thrown or else there would be a preferred direction of motion leading to perpetual motion.
a = (v2 - v1) / t = (v2 - 0) / 2 = v2 / 2 for a falling object
v2 = 2 a = 2 sec * 9.8 m/sec^2 = 19.6 m/s
You can check with
H = V0 t - 1/2 g t^2 (V0 and g are in different directions)
H = 0
V0 = 1/2 g * 4 = 19.6 m/s
write the importance of international Bureu of weights and Measures in the country.
Answer:
International Bureau of Weights and Measures (BIPM), French Bureau International des Poids et Mesures, international organization founded to bring about the unification of measurement systems, to establish and preserve fundamental international standards and prototypes, to verify national standards, and to determine fundamental physical constants. The bureau was established by a convention signed in Paris on May 20, 1875, effective January 1876. In 1921 a modified convention was signed.
Please help me to solve this question .
Answer:
P1 = momentum before collision = .5 kg * .32 m/s = .16 kg-m/s
Momentum is conserved
P1 = P2 = V * (M + m) = .16 kg-m/sec
V = .16 kg-m/sec / (.5 kg + .3 kg) = .2 m/sec
Someone help me please I don’t even know if that’s physics or not I just need help
Answer:
1. the robber carrying the metal safe will hurt more because the metal safe is heavier, so the heavier will be the force on the opposite direction from the one he was running when he hit the wall
2. ???
Explanation:
1. 3rd newton law: "If two bodies exert forces on each other, these forces are equal in magnitude and opposite in direction"
2. I don't know
If the activity of a source is 70 Bq after 2 years, and 35 Bq after 15 years. How long will be until the activity is 8.75 Bq?
Answer:
The SI unit for activity is one decay per second and is given the name becquerel (Bq) in honor of the discoverer of radioactivity. That is, 1 Bq = 1 decay/s. Activity R is often expressed in other units, such as decays per minute or decays per year.
how does a second class lever make our work easier
Answer:
In a second class lever, the load is located between the effort and the fulcrum. If the load is closer to the fulcrum than the effort, then less effort will be required to move the load. If the load is closer to the effort than the fulcrum, then more effort will be required to move the load.
Explanation:
from what i learned, if its farther away from the load, its easier to lift, like a wheel barrel
A projectile is shot on level ground with a
horizontal velocity of 17 m/s and a vertical
velocity of 34 m/s.
-Find the time the projectile is in the air.
The acceleration due to gravity is 9.8 m/s2.
Answer in units of s.
-Find range R.
Answer in units of m.
Answer:
time rising = 34 / 9.8 = 3.47 sec
total time in air = 2 * 3.47 sec = 6.94 sec
(time rising must equal time falling)
R = 17 m/s * 6.94 s = 118 m
Can also use range formula
R = v^2 sin (2 theta) / g
tan theta = 34 / 17 = 2
theta = 63.4 deg
2 theta = 126.9 deg
sin 126.9 = .8
v^2 = 17^2 + 34^2 = 1445 m^2/s^2
R = 1445 * .8 / 9.8 = 118 m agreeing with answer found above
un auto recorre 212 km en un tiempo de 3.1 h.Calcular su rapidez en m/s
Para hacerlo a m/s un método muy práctico es sólo dividir entre 3.6, por cuestiones de conversiones, lo puedes comprobar.
212 km/hr /3.6 = 58 m/s
Comprobación :
V= d / t
V= 212 m / 18000 seg <---- nota que aquí los segundos son de las 3.1hrs
V= 58 m/seg
Why did explorers want to find a way accross the North American continent
Answer:
The Desire for New Trade Routes
Extra:
European explorers found the New World by mistake; they were not looking to find new continents but new sea routes. Europeans mainly wanted to find better trade routes to China, India, and Southeast Asia.
please give brainliest if possible
What do you think will happen to current if we increase or decrease the resistance of the connecting wire?
Answer:
If resistance is increased, the current decreases and if the resistance is decreased, the current flowing through the wire increases.
Explanation:
V = IR is ohm's law which implies I = V/R, where I is the current and V is the voltage and R is the resistance. Hence, I is inversely proportional to R.
1. A sailboat accelerates uniformly from 3.0 m/s to 12.0 m/s at a rate of 1.5 m/s2. What distance does the boat travel?
Answer:
45 m
Explanation:
Use the equations of motion.
We know that:
S= the unknown
U=3 m/s
V=12 m/s
A=1.5 m/s
T= we won't need it
The equation used: [tex]v^2=u^2+2as[/tex]
Subsitute the values: [tex]12^2=3^2+2*1.5*s\\[/tex]
Solve the equation:
[tex]144=9+3s[/tex]
[tex]135=3s[/tex]
[tex]s=45 m[/tex]
what is the equation for newton’s second law of motion, in terms of mass, velocity and time, when the mass of the system is constant?
Answer:
Newton's second law of motion is F = ma, or force is equal to mass times acceleration.
If you ran at an average speed of 8 m/s, how long would it take you to run 200 meters?
To which kinds of objects do Newton's laws of motion apply?
only objects flying
only objects going down a hill
all objects
only objects rolling
Answer:
All objects
Explanation: Did test
I NEED A 100% ACCURATE ANSWER FOR THIS QUESTION ASAP NO LINKS !!!
Answer:
The answer is static friction. This is the friction that involves objects that do not move.
Explanation:
Friction is a force which opposes the motion of one object moving relative to another. static friction and kinetic friction are the two type of friction.
Static friction is that type of friction which keeps an object at rest. Force must be applied greater than static friction to move an object. Therefore it is the static friction which helps the pile of rocks from falling apart.
(Brainiest and thanks appreciated)
Answer:
static friction
Explanation:
I did a test like this yesterday same question different object
a large bottle contains a number of medicinal tablets each having a mass of 250mg the mass of all the tablets is 0.5kg calculate the number of tablets in the bottle
Considering the change of units and rule of three, the number of tablets in the bottle is 2,000.
First of all, you know that each medicinal tablet has a mass of 250 mg, while the mass of all tablets is 0.5 kg. You can see that the measurements are in different units of measurement, so you must make a change of units so that they are in the same units.
So, knowing that 1 kg is equal to 1,000,000 mg, you can apply the following rule of three: if 1 kg is equal to 1,000,000 mg, 0.5 kg is equal to how many mg?
1 kg ⇒ 1,000,000 mg
0.5 kg ⇒ x mg
So: [tex]x=\frac{0.5 kgx1,000,000 mg}{1 kg}[/tex]
x= 500,000 mg
Then, you know that each medicinal tablet has a mass of 250 mg, while the mass of all tablets is 500,000 mg. Now that the values are in the same units, to calculate the number of medicinal tablets you must apply the following rule of three: if 1 tablet has a mass of 250 mg, how many tablets have a mass of 500,000 mg?
[tex]number of medicinal tablets=\frac{500,000 mgx1 tablet}{250 mg}[/tex]
number of medicinal tablets= 2,000
Finally, the number of tablets in the bottle is 2,000.
Learn more:
brainly.com/question/12482948?referrer=searchResultshttps://brainly.com/question/24534599https://brainly.com/question/18328859?referrer=searchResultsAndy took a bus and then walked from his home to downtown. For the first 1.6 hour, the bus drove at an average speed of (15km)/(h). For the next 0.4 hours, he walked at an average speed of (4.5km)/(h). What was the average speed for the whole journey?
Answer:
240
Explanation:
a car is running with the velocity of 72km/h. what will be its velocity after 5s if its acceleration is -2m/s2 ?
Answer:
36 km / hr
Explanation:
velocity final = velocity initial + accel * time
20 m/s + (-2)*5 ( 20 m/s = 72 km/hr)
10 m/s ( or 36 km/hr)
please someone should help me and solve this is under Hooke's law
[tex]F=k(l_1-l_2)[/tex]
[tex]10=5k[/tex]
[tex]k=2[/tex]
[tex]15=2*(30-l_2)[/tex]
[tex]15=60-2l_2[/tex]
[tex]2l_2=45[/tex]
[tex]l_2=22,5cm[/tex]
Convert: 8 mm: ____________ cm
-1^10
centi=10 mm and mm=1/10=10^-1 cm
if a person with the arm dimensions shown pushes down hard with a 90 n force, what force must the triceps muscle provide? ignore the mass of the arm and hand in your calculation.
Answer:
1125 N
Explanation:
Which of the following would require more energy to heat it from 10°C to 20°C?
a. 200 kg of water
b. 200 kg of aluminum
C. 100 kg of steel
Answer:200kg of water
Explanation:
In the absence of friction, explain why the horizontal component of a projectile’s velocity is a constant.
Answer:
This downward force and acceleration results in a downward displacement from the position that the object would be if there were no gravity. The force of gravity does not affect the horizontal component of motion; a projectile maintains a constant horizontal velocity since there are no horizontal forces acting upon it
explain why so much thermal energy is released in a chain reaction
Answer:
It is the chain reaction process that is used in reactors and nuclear weapons to generate a large number of fissions. In a reactor, the propagation of fissions takes place in a controlled manner, in a nuclear weapon in an uncontrolled, explosive manner.
The products of nuclear fission are usually accompanied by two to three secondary, free neutrons which can be absorbed later by other fissile nuclei. These absorptions in turn lead to further fissions, then to the production of other neutrons etc ..., a process commonly called chain reaction.
15. A boy on board a cruise ship drops a 30.0 gram marble into the ocean. If the resistive force proportionality
constant is 0.50 kg/s, what is the terminal speed of the marble in m/s?
a. 0.06
b. 0.294
c.0.588
d. 60.0
e. 588.0
Physic about newton's law
1.
How much work done by Olympic gold medalist power lifter Hydilyn Diaz when she
pushes a car with a force of 900 N at a distance of 250m?
2.
How much work done by a tractor if a large rock is pushed with a force of 5000
N at 2.0 m/s for 20 seconds?
#1
Force=900NDisplacement=250m[tex]\\ \sf\longmapsto Work=Force(Displacement)[/tex]
[tex]\\ \sf\longmapsto Work=900(250)[/tex]
[tex]\\ \sf\longmapsto Work=225000J[/tex]
[tex]\\ \sf\longmapsto Work=225KJ[/tex]
#2
Displacement=2(20)=40mForce=5000N[tex]\\ \sf\longmapsto Work=40(5000)[/tex]
[tex]\\ \sf\longmapsto Work=200000J[/tex]
[tex]\\ \sf\longmapsto Work=200KJ[/tex]
According to newtons third law if an eighth grader pushed against a large boulder with a force of 8 N how much force would the boulder exert on the eighth grader
Answer:
8n
Explanation
Ok, so the runner then goes from 20m to 11m. Distance? Displacement?
Answer:
honestly a bit confused by the question, but this would be a 9 meter difference in the distance, moving from 20m to 11m
Explanation:
Which can lead scientists to change a theory that has already been accepted? Check all that apply.
changes to scientific laws
new experimental methods
new hypotheses
technological inventions
repetitions of old experiments
Answer:
B, C, and D
Explanation:
PLEASE I NEED HELP 35 POINTS PLSSSS
Answer:
i think the products have four hydrogen atoms and two oxygen atoms and the reactants have the same atoms in two molecules of h2o