A man standing on top of a 30 m tall building throws a brick downwards with a velocity of 12 m/s. Determine the speed of the brick just before it hits the ground.

Answers

Answer 1

Answer:

27.1m/s

Explanation:

Given parameters:

Height of the building  = 30m

Initial velocity  = 12m/s

Unknown:

Final velocity  = ?

Solution:

We apply one of the kinematics equation to solve this problem:

         v²  = u²  + 2gh

v is the final velocity

u is the initial velocity

g is the acceleration due to gravity

h is the height

          v²   = 12²  + (2 x 9.8 x 30)

          v  = 27.1m/s


Related Questions

Sam is moving house and is carrying a 300N box of books up a flight of steps 5m high, it takes her 30 seconds. Gary follows her carrying a bag of clothes doing 1000 J of work; it only takes him 25 seconds. Who provides the biggest power? Show your working.

Answers

Answer:

Sam is providing the biggest power i.e. 50 W

Explanation:

Sam is moving house and is carrying a 300N box of books up a flight of steps 5m high, it takes her 30 seconds.

Sam's power :

[tex]P_1=\dfrac{W_1}{t_1}\\\\P_1=\dfrac{F_1d}{t_1}\\\\P_1=\dfrac{300\times 5}{30}\\\\P_1=50\ W[/tex]

Gary follows her carrying a bag of clothes doing 1000 J of work; it only takes him 25 seconds.

Gary's power :

[tex]P_2=\dfrac{W_2}{t_2}\\\\P_2=\dfrac{1000}{25}\\\\P_2=40\ W[/tex]

So, it is clear that Sam is providing the biggest power.

magnetic field strength decrease when what is increases

Answers

Ans: One way to increase or decrease the strength of the magnetic field is to change the number of loops in the coil. The more loops you add, the stronger the field will become. The more loops you remove, the weaker the field will become.

What is osomsis and diffusion ​

Answers

Answer:

Osmosis is the movement of solvent particles across a semipermeable membrane from a dilute solution into a concentrated solution. ... Diffusion: Diffusion is the movement of particles from an area of higher concentration to lower concentration. The overall effect is to equalize concentration throughout the medium.

6. In baseball, a fastball takes about 1/2 second to reach the plate. Assuming that such a pitch is thrown horizontally, compare the distance the ball falls in the first 1/4 second with the distance it falls in the second 1/4 second.

Answers

Answer:

The ball falls 0.3 m in the first 1/4 seconds, and it falls 0.92 m in the second 1/4 second

Explanation:

Horizontal Launch

When an object is thrown horizontally with a speed v from a height h, it describes a curved path ruled exclusively by gravity until it eventually hits the ground.

To calculate the vertical distance (y) traveled by the object in terms of the time (t) we use:

[tex]\displaystyle y=\frac{g.t^2}{2}[/tex]

The fastball is thrown horizontally. The distance the ball falls in t=1/4 seconds = 0.25 seconds, is:

[tex]\displaystyle y_1=\frac{9.8*0.25^2}{2}[/tex]

[tex]\displaystyle y_1=0.30625\ m[/tex]

The distance the ball falls in t=1/2 seconds = 0.5 seconds is:

[tex]\displaystyle y_2=\frac{9.8*0.5^2}{2}[/tex]

[tex]\displaystyle y_2=1.225\ m[/tex]

The distance it falls in the second 1/4 second is:

[tex]y_2-y_1=1.225\ m-0.30625\ m[/tex]

[tex]y_2-y_1=0.91875\ m[/tex]

The ball falls 0.3 m in the first 1/4 seconds, and it falls 0.92 m in the second 1/4 second

A ray diagram is shown.

Answers

Answer:

Angle of Refraction ?

Explanation:

My decided answer on this question

6. Which phase of matter has a definite volume and shape.
a. solid
b. liquid
c. gas
d.plasma

Answers

Answer:

solids

Explanation:

beacause if you take an ice cube does it change its shape no and if it has a definite shape it is sure to have a definite volume

Which of the following determines and objects ability to float in water

Atomic number

Mass and volume

Displacement in a liquid

Mass and gravity

Answers

I think its
Mass and volume

why do prescribed drugs need to be prescribed by doctors what can happen if you abuse these drugs without a pressure?

Answers

Answer:

unperscriebed drugs can e harmful to your body

Explanation:

How do I find the change in velocity of a hockey puck?
Mass=0.1697 kg btw

Answers

Answer:The foot exerts a force on the ball during a well-defined

duration t (time extent of the contact)

Explanation:

If the body's temperature is above 105 °F for a prolonged period, heat stroke
can result. Express this temperature on the Celsius scale.
OA 40.5°C
OB 58.3°C
OC 76.1°C
KOD 131.4°C

Answers

Answer:

A

Explanation:

C = (F-32)*5/9 = 73*5/9 = 40.55555

since the answers are spread apart, technically you can just estimate by doing -32

and then /2

since 5/9 is close to 1/2

A golfer hits a golf ball upwards at an angle. We can ignore air resistance on the ball.
Which diagram best describes the velocity vectors and trajectory of the golf ball's motion?

Answers

Answer:

Check the diagram from the photo

Explanation:

Energy that depends upon object mass and object height.

Answers

Answer:

That is Gravitational potential energy.

Help me please with science

Answers

Answer:its b

Explanation:

You look at yourself in the mirror and notice many of your physical features: your hair color, eye color, your height, dimples, etc. How does DNA relate to the way you look the way you do?

Answers

well, you get some DNA from both of your parents, so when you hear the phrase, "You have your mother's eyes!" That means you have some of your mother's DNA that gave you her eye color. The DNA you get from your parents help determine how you look today


On the pH scale, where can you find strong acids and strong bases?

Answers

Answer

Higher number = strong acids

Explanation:

The pH scale is an index ranging from 0-14 which measures the acidity or basicity of substances. The closer the pH of an acid to 0 the stronger it is and the closer the pH of a base to 14,the stronger it is.

How can shorter string produce more fundamental frequency in two string of different length?​

Answers

Answer:

Shorter string produces more frequency in two different strings because the equation for frequency is velocity/wavelength , this means that a shorter string creates a shorter wavelength which essentially increases the total frequency produced

What conclusion can you draw from the information shown in the graph?
O A. Global temperatures are increasing due to human activity.
B. Earth is currently experiencing a period of global warming.
O C. Temperature is the only aspect of climate that is changing.
O D. Global temperatures are increasing due to natural causes.

Answers

Answer:

The correct option is;

B. Earth is currently experiencing a period of global warming

Explanation:

From the graph, we have;

1) From 1880 to 1900 the temperature anomaly (°C) averages a few degrees below the average surface temperature

2) The decrease below the average surface temperature is larger from  1900 to 1920

3) The surface temperature rises more steadily from below average to a little above average from 1920 to 1940

4) Between 1940 to 1980, the temperature hovers around the average surface temperature

5) The Earth's surface temperature is more or less steadily increasing from 1960 to present

Therefore, the Earth is experiencing a period of global warming

An LED light bulb is favored over an incandescent light bulb because it is more , what?

Answers

An LED light bulb is favoured because it is more bright.

An LED light is favored over an incandescent light bulb because it is more bright than the incandescent bulb.

What is an LED bulb?

An LED is a light emitting diode. It is used widely for the production of light because it shows some advantages which include:

Many traditional lighting systems like the incandescent bulbs turn more than 90% of the energy which they use to heat, allocating only about  10% of energy to actual light production. LEDs emit almost no heat energy, and most of the light energy they emit is within the visible spectrum.

LEDs use much less energy than that of incandescent bulbs because the diode light is much more efficient, power-wise, than the filament light. LED bulbs use more than 75% less energy than those of incandescent lighting.

Learn more about LED bulb here:

https://brainly.com/question/30272515

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Which is NOT a part of an electric motor?
a.
armature
b.
brushes
c.
commutator
d.
slip ring

Answers

D. Slip ring, hope this helps

A ball is pushed into a spring-loaded launcher with a force of 20 N, which compresses the spring 0.08 m.
A) What is the spring constant of the spring
B) Find the elastic potential energy (PEs) stored in the spring (or the work done on the spring)

Answers

Answer:

0.8J

Explanation:

Given parameters:

Force  = 20N

Compression  = 0.08m

Unknown:

Spring constant  = ?

Elastic potential energy  = ?

Solution:

To solve this problem, we use the expression below:

           F = k e

F is the force

k is the spring constant

e is the compression

             20  = k x 0.08

              k  = 250N/m

Elastic potential energy;

       EPE  = [tex]\frac{1}{2}[/tex] k e²    =  [tex]\frac{1}{2}[/tex]  x 250 x 0.08²

 Elastic potential energy = 0.8J

Select the correct answer.
Which diagram represents an object in equilibrium?
ОА.
applied
force = 20 N
force due to
friction = 15 N
OB.
applied
force = 20 N
force due to
friction = 20 N
OC.
applied
force = 15 N
force due to
friction = 25 N
OD.
applied
force = 30 N
force due to
friction = 20 N
ОЕ.
applied
force = 30 N
force due to
friction = 15 N
Reset
Next
My

Answers

Answer:

B

Explanation:

The force and friction cancel each other.

20N - 20N = 0N acting on the object.

in 1965, two scientists made a surprising discovery. they detected a faint microwave radiation signal coming from all over the universe
what is this microwave radiation?i’ll give brainlist

Answers

Answer: someone took down my answer I don’t know why when I took this test and got it right but the answer is C like the other person said.

Explanation:

The microwave radiation referred to in this context is radiation that was released as matter formed in the early universe. Therefore option A is correct.

Microwave radiation, also known as cosmic microwave background radiation (CMB), is a faint radiation that permeates throughout the universe.

It is considered to be the remnants of the thermal radiation released shortly after the Big Bang, during a phase called recombination. At this time, the universe transitioned from a hot, dense plasma to a state where neutral atoms could form, allowing photons to travel freely.

The cosmic microwave background radiation is isotropic, meaning it is uniformly distributed in all directions, and it has a characteristic temperature of approximately 2.7 Kelvin (-270.45 degrees Celsius).

It was first detected in 1965 by Arno Penzias and Robert Wilson, who were awarded the Nobel Prize in Physics for their discovery.

The presence of cosmic microwave background radiation provides strong evidence for the Big Bang theory and helps to support the understanding of the early universe's formation and evolution.

It serves as an important tool for studying cosmology and provides insights into the structure, age, and composition of the universe.

Know more about CMB:

https://brainly.com/question/30416668

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What causes wind to follow patterns

Answers

Answer: Wind follows a pattern because the Earth is spinning in one motion. If we were spinning in one way then another we would have one day go by then the spinning cycle would change and we would have to go through that day all over again, it would not be logical because then we would be in the same season as well, we would be in one season for the rest of our lives until we died.

I don't know if this was helpfull or not but I hope it was somewhat close to helpful? If it is not then please do not report this, I am sorry if this was the least bit helpful.

HAVE A NICE DAY! :)

What is the kinetic energy of a 74.0 kg man traveling in a car at a speed of 52.0 m/s?

Answers

Kinetic energy = 1/2mv^2
Mass m=74kg
Velocity C=52m/s
K.E= 0.5*74*52*52
K.E=100048J or 100.048kJ

Which of the following is an example of kinetic energy?


athlete running in a race

battery charging in a garage

apple hanging from a tree

water boiling on a stove

Answers

Answer:

A. Athlete running in a race

Explanation:

Kinetic energy haves something to do with movement

Athlete running in a race
Why: I took the test

4. Describe solids and
give an example.

Answers

Answer:

A solids molecules are tightly packed to get her and an examle of a sold is a rock

Explanation:

Solids is a solid or hard molecules

Using the information given, find the Atomic Mass of the unknown element: 12 PROTONS, 12 NEUTRONS, 12 ELECTRONS​

Answers

Answer:

A. 12

Explanation:

Answer is 12

Explanation

Which graph accurately shows the relationship between kinetic energy and mass as mass increases

Answers

Answer:

c

Explanation:

energy doesnt affect to mass of a object

friction that resists the motion between two objects that are not moving

Answers

Answer:

static friction is the friction that resists the motion between two objects that are not moving

Hooke's Law Question - Will mark brainliest

A spring of natural length 10cm and spring constant 4.00Ncm −1 has a load of 22.0N placed on it. What is its new length?

Answers

Explanation:

Hooke's Law: Fe = kx

x = Fe / k = (22.0N) / (4.00N/cm) = 5.50cm.

10.00cm + 5.50cm = 15.50cm

The new length of the spring is 15.50cm.

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