A student ties a ball at the end of a string and whirls the string at a constant speed. If the radius of the circle along which the ball moves is 1.2 m and the acceleration is 7.5 m/s2what is the speed of the ball?

Answers

Answer 1

a = v ² / R

where a is acceleration, v is speed, and R is the radius. So

7.5 m/s² = v ² / (1.2 m)

v ² = (7.5 m/s²) / (1.2 m)

v ≈ 6.8 m/s


Related Questions

You have a bowling ball with a mass of 4kg. You throw it with an acceleration of 10 m/s/s. With how much force will it hit the pins?

Answers

Answer:

The answer is 40 N

Explanation:

The force acting on an object can be found by using the formula

force = mass × acceleration

From the question

mass = 4 kg

acceleration = 10 m/s²

So we have

force = 4 × 10

We have the final answer as

40 N

Hope this helps you

1.a car sitting at rest on the road
balanced or unbalanced
explain your answer​

Answers

Answer:

Balanced force

Explanation:

Balanced Forces, When forces are in balance, acceleration is zero. Velocity is constant and there is no net or unbalanced force. ... Although friction is acting on the person, there is no change in velocity and friction is not a net force in this case. Friction is only a net force if it changes the velocity of a mass.

The car is balanced.

If there are any forced acting on it, then those are balanced too.

How does the approximate number of atoms
in the air in your lungs compare to the num-
ber of breaths of air in the atmosphere of the
whole world?

I don’t understand what this is asking...

Answers

Consider the Earth as a sphere. Think of the atmosphere as having a height of say about 20000 m. The volume of a sphere is 4/3 * pi * r ^3.
Find the volume of a sphere of radius 6020000 m and subtract the volume of the Earth which is a sphere of radius 6000000 m (approx).
This would be the volume of air in m^3.

Approximate the lungs as a cube, it would be approx 0.2m x 0.2m x 0.2 m = 0.008 m^3

Divide the volume of air around the Earth by 0.008.

0.001 m^3 of air contains about 6 x 10^23 molecules which is about 12 x 10^23 atoms.

If your lungs are 0.008 m^3 then that would be about 96 x 10 ^23 or about 10^25 atoms.

Compare that number with the earlier number when dividing air in the atmosphere by 0.008.

I hope this helps. :)

Light waves pass through two openings and interfere, producing light and dark areas. Which of the following statements is true with regard to the areas that are produced?

A.The bright areas are produced by the destructive refraction of light waves.
B.The dark areas are produced by the destructive refraction of light waves.
C.The dark areas are produced by the constructive interference of light waves.
D.The bright areas are produced by the constructive interferences of light waves.

Answers

i think it’s B. The deal areas are produced by the destructive refraction of light waves

what will be the resistivity of a metal wire of 2m length and 0.6mm in a diameter ,if the resistance of the wire is 50ohm . find the resistance of the same wire of 2m length and 0.3mm thickness​

Answers

Answer:Resistivity of the wire is 7.065 × 10^-8 Ω m.

Explanation:

I have no idea i just googled it

Why is the law of gravity an example of a universal law?


A. Gravity exists between small masses in an open system only.


B. Gravity exists between any two masses.


C. Gravity exists only on the earth and the moon.


D. Gravity exists for masses in a closed system only.

Answers

The answer is B. No matter where you go, you could go to another galaxy, you will always experience gravity. And that happens because of two massive objects. That’s why the law is universal. It’s true for any spot in the universe

Answer:

B

Explanation:

i took the test

A doctor pushes the plunger of syringe down and then pulls it up to a draw liquid into a syringe? give reason please help me with very short answer

Answers

Answer:

When the doctor has the syringe, it is full of air. So, now after the doctor pushes the plunger, hence the air gets released into the medicine container. After this the doctor then takes the plunger and pull it back. Now , the air gets pulled up back into the syringe, but not only does the air come in but also the medicine because of the pressure build up.

If my answer helped, please mark me as the brainliest!!

Thank You!

DESPERATE WILL GIVE BRAINLIST
How long does it usually take for a rock to undergo a stage within the rock cycle?
A. a few days
B. from 300 to 400 years
C. about one thousand years
D. thousands to millions of years

Answers

Answer: D. thousands to millions of years

Explanation: Stages within a rock's cycle cannot happen quickly. The formation and deterioration can take thousands to millions of years to occur.

I hope this helps!

Good luck <3

How can a person’s movement away and towards a reference point be analyzed using a position-time graph?

Answers

Answer:

Explanation:

You can plot their change in position per unit of time. By taking the slope of this graph, you can figure out the velocity at any point

Does change in direction affect the acceleration of a car?

Answers

Answer:

A change in velocity is either a change in an object's speed or its direction. When a moving object changes direction, its velocity changes and it is accelerating.

Explanation:

Yes, but it’s not the only thing that changes it.

Atoms are known to form charges due to their ability to gain and lose electrons in reactions. As a result, atoms
become ions that are positively or negatively charged depending on the loss or gain of electrons. Which of the
following atoms has a charge of +2 given the number of electrons?
O A. O: 10 electrons
OB. N: 10 electrons
O C. Fe: 24 electrons
OD. Cl: 18 electrons

Answers

Answer:

C. Fe: 24 electrons

Explanation:

From the analogy given, the atom with a charge of +2 is Fe having 24 electrons.

To calculate the charges on an atom;

     Number of charges = Number of protons - Number of electrons.

   O: 10 electrons: 8 protons = 8 - 10 = -2

   N: 10 electrons; 7 protons = 7 - 10 = -3

   Cl: 18 electrons; 17 protons = 17 - 18 = -1

So;

    Fe: 24 electrons and 26 protons = 26 -24  = +2

Therefore, the solution is Fe

A parachute on a racing dragster opens and changes the speed of the car from 79.33 m/sec to 41.55 m/sec in a period of 5.21 seconds. What is the acceleration of the dragster?

Answers

Answer:

c: -7.25

Explanation:

Here we can use the equation v=u+at

Where v is the final velocity

u is the initial velocity

a is acceleration

and t is time

41.55=79.33+a(5.21)

41.55-79.33=5.21a

-37.78=5.21a

a=-7.25 m/[tex]s^2[/tex]

The negative sign is due to the fact that they are slowing down

Find kinetic energy if that same mass is now moving at a velocity of 3 m/s

Answers

Answer:

what is the mass???

Explanation:

just take the mass(kg) and half it

then take the halved mass and multiply it by 3 m/s

why light waves are called electromagnetic waves ?​

Answers

because they have electric and magnetic fields. if it contains a low frequency, it has less energy and could possibly be a radio or a tv wave.

You are at the Super Bowl. The coach puts you in during the 4th quarter to be the quarterback to secure your team the win. Since you are fresh off the bench, you are able to throw the ball with more force than the last person. What advantages, using Newton's second law, will this have when playing?

Answers

Answer:

the ball will fly faster, and longer distance, which means there is going to be less air resistnace friction acting upon the ball.

Explanation:

F = ma

Force = mass x acceleration

Mass of football remains constant, fresh arm of QB provides higher acceleration.


Ball will get to receiver faster.

A balloonist drops his camera from a height of 100 m while his balloon is ascending at 5 m/s. How
long did it take to reach the ground?

Answers

20 i think is the answer

An automobile traveling along a straight road
increases its speed from 53 ft/s to 68 ft/s in
180 ft.
If the acceleration is constant. how much
time elapses while the auto moves the 180 ft?
Answer in units of s.

Answers

Answer:

t = 2.97[s]

Explanation:

To solve this problem we must use the following kinematics equations, we must bear in mind that the positive sign of the acceleration value means that the car is increased its speed.

[tex]v_{f}^{2} =v_{o}^{2} +(2*a*(x-x_{o} ))[/tex]

where:

x - xo = 180 [ft]

a = acceleration [ft/s^2]

Vo = initial velocity = 53 [ft/s]

Vf = final velocity = 68 [ft/s]

Now replacing we find:

(68^2) = (53^2) + (2*a*180)

a = 5.04 [ft/s^2]

Now using the following equation:

[tex]v_{f}=v_{0}+a*t[/tex]

68 = 53 + (5.04*t)

t = (68 - 53)/5.04

t = 2.97[s]

If the mass of one object is doubled and mass of other remains the same and if distance between them is halved then how does the gravitational force change?

Answers

Force is proportional to the product of masses and inversely proportional to the square of the separation.

New force = 8 x original force

Tim was recently released from his last job. He was very rigid and would not change a product design once he began a project. He is now working for a new engineering firm and has learned from his last mistake. He is willing to meet with clients to change the needs of each and every situation. As a result, his work is now .

Answers

Answer:

Flexible and responsive to the clients requests

Explanation:

Change in design is the alteration of the specification of a product based on present or current requirements, as such change in design can take place at any stage of a product life cycle.

However, it is more cost effective to make changes to the design at the early stages of a product than at the later stages, due to the cost incurred in making adjustments and the previous expenses incurred if the design that was later changed had moved into more advanced stages.

When you travel 20km in 1 hour, at what speed do you travel.

Answers

Answer:

at 20km/h

Explanation:

A car travels from 20-meters to 60-meters in 10 seconds. Calculate the car's speed.

Answers

Answer:

8 m/s

Explanation:

All you have to do here is add 20 and 60 (giving you 80) and dividing by 10 seconds. 80/10= 8 m/s

Have you ever wondered how a vending machine "knows" that you have put in the correct amount of change to purchase a snack or a drink? These machines use coin detectors that determine the mass and the size of the coins deposited. In other words, they analyze the density of the coins. United States coinage is minted within very narrow specifications, so the density of each type of coin is always the same. The coin detectors compare the coins inserted to the preset standards to determine if the correct combination of coins has been deposited. In this lesson, you too will determine the density of various coins. OBJECTIVES Recognize the characteristics of density. Design and carry out a scientific investigation. Present your findings in a scientific report. Online Lab This animation will allow you to find the density of a penny, a nickel, and a quarter. Make a hypothesis in which you suggest which coin will have the highest density and which will have the lowest density. A model hypothesis might be: "If the (fill in the name of a coin) has a greater density than the _____ and _____, then it will have a greater mass to volume ratio. If the (fill in the name of a coin) has a lower density than the _____ and _____, then it will have a lower mass to volume ratio. Remember to record your data and observations in the data sheet so that you can use them to present your findings. SHOW TRANSCRIPT Present Your Findings Write a one or two summary paragraph discussing this experiment and the results. Use the following questions and topics to help guide the content of your paragraph. According to your data, was your hypothesis correct? (Be sure to refer to your data when answering this question.) Summarize any difficulties or problems you had in performing the experiment that might have affected the results. Describe how you might change the procedure to avoid these problems. List at least two real world examples that apply the findings of this experiment. (Hint: An example of this type was given in the introduction to this project.) What would you like to do next?

Answers

Answer:

If the Quarter has a greater density than the nickel and penny, then it will have a greater mass to volume ratio.

Explanation:

sorry thats all i can help with!

Question: Carbon Dioxide is a serious danger because if causes...?

Answers

Answer:

Symptoms of carbon dioxide toxicity include high blood pressure, flushed skin, headache and twitching muscles

Hope this helps :)

A general contractor drives 5 miles to the hardware store in 10 minutes. He shops for needed tools for 30 minutes, then drives to his customer’s home at an average speed of 45 mph. He arrives 20 minutes later. Calculate the average speed from the time the contractor leaves his office to the time he arrives at his customer’s home.

Answers

Given parameters:

Distance to hardware shop = 5 miles

Time to reach hardware shop = 10 minutes

Time spent at the shop = 30 minutes

Average speed to customer home = 45 mph

Time taken for the travel = 20 minutes

Unknown:

Average speed of the contractor = ?

Solution:

 Average speed is the total distance covered divided by the total time taken.

   Average speed = [tex]\frac{total distance}{total time taken}[/tex]  

     total distance = distance to hardware shop + distance to customer's home

We do not know the distance to customer's home but we have been given the speed and time, so we can find the distance.

  Distance  = speed x time

 Convert the time to hrs and solve;  

                       60 minutes  = 1 hr

                       20 minutes  = [tex]\frac{20}{60} hr[/tex]  = [tex]\frac{1}{3} hr[/tex]

So, Distance  = 45mph x [tex]\frac{1}{3} hr[/tex]   = 15miles

Now;

   Total distance  = 5 + 15 = 20miles

Total time = time to reach hardware shop + time to reach customer's house

                  = 10 + 20

                  = 30 minutes

Convert the time from minutes to hrs;

                 60 minutes  = 1hr

                 30 minutes  = [tex]\frac{30}{60}[/tex]   = 0.5hr

So;

    Average speed  = [tex]\frac{20}{0.5}[/tex] = 40mph

The average speed is 40mph

in a series circuit, why is the current always the same?

Answers

Answer:

here lol

Explanation:

An airplane flying due north at 90km/h is being blown due west at 50 km/h. What is the magnitude of the resultant velocity of the plane?

Answers

Answer: 103 km/hr

Explanation:

Guessed on ck-12 and it ended up being right.

Answer:

50

Explanation:

He/she guessed...Ig its 50.

9. What force is felt on a person when they 'free-fall down a large roller
coaster hill?

Answers

Gravity is counteracted by centripetal force, due to acceleration, which is the force that pushes you into your seat.

Hillary is dropping objects that are the same volume. She wants to investigate how an object’s mass affects the average speed at which it travels when dropped, until it hits the ground. Which variable must Hillary change during the experiment?


A. the timer
B. the drop height
C. the mass of the object
D. the place where she drops it

Answers

Answer:

letter C. The mass of the object.

Explanation:

i hope it helps.

Diamonds have a score of 10 on the Mohs scale. Therefore, they are used in grinding belts to buff and smooth other materials. What physical property is demonstrated by this? brainly

Answers

Answer:

Hardness

Explanation:

It has a score of 10 on the Mohs scale of HARDNESS

Noble Gases do not readily form compounds because they ___ chemically stable with 8 valence electrons

Answers

Answer : Noble Gases do not readily form compounds because they are chemically stable with 8 valence electrons.

Explanation :

Noble gases are the chemical elements that are present in group 18 in the periodic table.

The elements are helium, neon, argon, krypton, xenon and radon.

They are chemically most stable except helium due to having the maximum number of 8 valence electrons can hold their outermost shell that means they have a complete octet.

They are rarely reacts with other elements to form compounds by gaining or losing electrons since they are already chemically stable.

Hence, the noble Gases do not readily form compounds because they are chemically stable with 8 valence electrons.

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