PLEASE HELPP
Select ALL the correct answers.
Which of these factors make hydrogen fuel cells a better option than burning fossil fuels?
1. Hydrogen fuel cells have a higher energy efficiency.
2. Hydrogen fuel cells create less pollution.
3. Burning fossil fuels relies on outdated devices and technology.
4. Hydrogen is the most abundant element in the universe.
5.Hydrogen fuel cells are more expensive than fossil fuels.
Answer:
Hydrogen fuel cells have a higher energy efficiency.
Hydrogen fuel cells create less pollution.
Explanation:
During which changes of state do atoms overcome the attractive forces between them?
A freezing and condensation
B boiling and deposition
C condensation and melting
D vaporization and sublimation
Answer:
D) vaporisation and sublimation
Explanation:
Answer:
D
Explanation:
vaporization and sublimation
The FITT principles of training include __________.
A.
fundamental, intensity, time, and type
B.
frequency, intensity, time, and type
C.
frequency, individual, time, and type
D.
frequency, intensity, tough, and time
Please select the best answer from the choices provided.
Answer:
IT Will be Answer choice B
Explanation:
frequency, intensity, time, and type
FITT (frequency, intensity, time, and type) is one way to remember the general guidelines for what should be included in a fitness plan.
Answer:
B. frequency, intensity, time, and type
Explanation:
^^^^
How much would a 1000 gram soccer ball accelerate if I kicked it with a force of 15 N?
Answer:
15m/s2
Explanation:
Acceleration = Force / Mass
Acceleration = 15N / 1kg
Acceleration = 15m/s2
3. Elizabeth tested how high five different brands of new tennis balls would bounce when dropped from the same height of 2 meters. She dropped the balls so that they hit the same floor tile each time. In this consumer testing she did not have a control experiment but took factual information from the manufacturers on how well their product bounced (resiliency). She tested 100 balls of each brand. She measured the bounces in centimeters. what is the controlled variable and the Independant variable and the dependent variable
Answer:
Controlled variable: the height from which the ball is dropped and the floor tile on which the ball hits
Independent variable: different tennis ball brands
Dependent variable: height of bounce in centimeters
Explanation:
Scientific experiments have three major kinds of variables:
Independent variable: This is the variable that is subject to the manipulation of the experimenter. The values of this variable are determined by the experimenter. In this example, Elizabeth determines the brand of tennis ball to be tested, hence the tennis ball brand is the independent variable
Dependent variable: This variable has values which are a result of the effect of the manipulation of the independent variable. The values of the dependent variable are not under the direct control of the experimenter. They are simply the results of the experiment. Here, the height to which the ball bounces is not predetermined, hence it is the outcome or dependent variable.
Control variables; These are variables that can affect the outcome of the results of the experiment but are kept constant throughout the experiment, to rule out biases when testing the effect of the independent variable.
what would be the distance a bomb traveled in the X direction if it fell out of an airplane at 25,000 meters high and was traveling 50 meters per second.
Answer:
The bomb will land at approximately 3.5 Km
Explanation:
Horizontal Motion
The bomb is thrown horizontally by an airplane with a speed v=50 m/s from a height h=25,000. The range or maximum horizontal distance traveled by the object can be calculated as follows:
[tex]\displaystyle d=v\cdot\sqrt{\frac {2h}{g}}[/tex]
[tex]\displaystyle d=50\cdot\sqrt{\frac {2*25,000}{9.8}}[/tex]
[tex]\displaystyle d=3,571.43\ m[/tex]
The bomb will land at approximately 3.5 Km
20. A hurricane in the Gulf of Mexico travels 360 km in 15 h. What is the average speed of this hurricane?
Answer:
The average speed of this hurricane is 24 kph.
Explanation:
let me know if this helps
How much mass is required to exert a force of 25 Newtons, accelerating at 5 m/s2?
help pleaseee!
Answer:
5
explanation:
25 divided by 5
Answer:
25/5= 5
Explanation:
Issac throws an apple straight down from a tree with an initial speed of 5.0 m/s
Answer:
what's the question to this
I really need help plz
fzfgf1234556887543113
Answer:
true!! hope this helps
it has to be 20 characters ignore my extra typing
What is the acceleration of a car that moves in a straight line and decreases its speed from 80km/hr to 15km/hr in exactly 5.0 seconds
Answer:
-3.6 m/s
Explanation:
first go from km/hr to m/s
so 80km/hr⇒ 22.2222 m/s
15km/hr ⇒4.16667 m/s
now use the equation for acceleration
[tex]\frac{v-v0}{t}[/tex]
(4.16667-22.2222)/5 = 18.05553/ 5 = -3.611106 m/s
with sig figs
-3.6 m/s
What is true about the electric and magnetif fields as the electromagnetic wave moves?
a The angle between them is constantly increasing
b the angle between them is decreasing
c They are parallel
d They are perpendicular (90º)
Answer:
d They are perpendicular (90º)
Explanation:
When electric and magnetic fields moves they are perpendicular to one another.
Electromagnetic fields are composed of both electric and magnetic fields. In motion, the two fields moves perpendicular to one another. These waves are mostly generated through natural activities. They are called transverse waves and moves perpendicular to the particles. Examples are light waves, radio waves, etc.a dog with mass of 14kg has a kinetic energy of 135.5j. what is the speed of the dog
Answer:
v = 4.39968 m/s
v = 9.8418038654259 mi/h
v = 14.434645669291 ft/s
v = 15.838846732892 km/h
Explanation:
v=KE/1/2m
Why is visible light between infrared and ultraviolet
Answer:
The infrared has longer wavelengths (700 nm to 1 mm) than those of visible lights (390 nm to 700 nm). Note though that visible light is the only radiation that can be seen by the human eye. The ultraviolet is much more intense and has a shorter wavelength (400 nm to 10 nm) compared to visible light.
Explanation:
GREETINGS!
Visible light is in between UV and IR region because visible light has a wavelength ranging from 400nm to 700nm, and below 400nm is the region of UV and above 700 is the region of IR, So visible lights is in between UV and IR
To understand things more clearly you could see the electromagnetic spectrum to see which ray lies lies in what region.
HOPE THIS HELPS YOU
Which two phrases describe the nature of an electromagnetic force?
A. Not a fundamental force of nature
B. Produced by interactions between magnetic objects
C. Acts only when objects tough each other
D. Produced by interactions between electrically charged objects
Answer:
I think its C and D
Explanation:
Atoms are neutral in electric charge because they have the same
number of negative electrons as positive protons, and the electric
charges "cancel out."
A: True
B: False
Acids and bases are compounds with very different properties. Which of the following is a property of an acid?
Answer:
reacts to mos metlal
Explanation:
An object starts at position 12 on a horizontal line with a reference point of 0. What is the position of the object if it moves 14 units to the left?
–26
–2
2
26
Answer:
Answer is negative -2 think about this is basically a sbrtaction problem the number starts at 12 and then it moves 14 to left which means backwards so 12-14=-2 so thats were u get -2 as your answer.
Explanation:
wanted to help people plus I am doing the quiz right now.
A boy on his skateboard is accelerating at a rate of 5 m/s2 and has a mass of 40kg. How much force does the boy on his skateboard have?
Answer:
The answer is 200 NExplanation:
The force acting on an object given it's mass and acceleration can be found by using the formula
force = mass × acceleration
From the question we have
force = 40 × 5
We have the final answer as
200 NHope this helps you
what is the average speed of a person who swims 105m in 70s ?
Answer:
v = 1.5 [m/s]
Explanation:
This problem can be solved using the definition of velocity which is the relationship between space and time.
v = x/t
where:
v = speed [m/s]
x = distance = 105 [m]
t = time = 70 [s]
v = 105/70
v = 1.5 [m/s]
Answer:time.
v = x/t
where:
v = speed [m/s]
x = distance = 105 [m]
t = time = 70 [s]
v = 105/70
v = 1.5 [m/s]
Explanation:time.
v = x/t
where:
v = speed [m/s]
x = distance = 105 [m]
t = time = 70 [s]
v = 105/70
v = 1.5 [m/s]
A motorcyclist started a race from START line and from rest, and accelerated with the acceleration of 2 m/s2 for 7 seconds. Then he increased the acceleration to 4 m/s2 and went with that acceleration for 8 seconds. What was the racer’s position from the START line after 7+8 seconds from the start of the race?
Answer:
289 m .
Explanation:
s = ut + 1/2 at² , u is initial velocity , t is time , a is acceleration and s is distance covered .
For t = 7 s
s = 0 + 1/2 x 2 x 7²
= 49 m
velocity after 7 s
= a x t = 2 x 7 = 14 m /s
for next 8 s , initial velocity u = 14 m /s
S = ut + 1/2 at²
= 14 x 8 + 1/2 x 4 x 8²
= 112 + 128
= 240 m
Total displacement in 7 + 8 s
= 49 + 240 = 289 m .
Increased globalization has been caused by all of the following except
A improved technology
B. increased transportation speeds
C. improved communication speeds
D. decreased distances between nations
Please select the best answer from the choices provided.
Answer: D. decreased distances between nations
just did test on edge
i really need brainliest plz
A motorcyclist started a race from START line and from rest, and accelerated with the acceleration of 2 m/s2 for 7 seconds. Then he increased the acceleration to 4 m/s2 and went with that acceleration for 8 seconds. What was the racer’s position from the START line after 7+8 seconds from the start of the race?
Answer:
.
Explanation:
If a student leaves home at 7:30 AM to walk to his school 2 km away, stops at a neighbor's house for 15 min, then arrives at school at 8:00 AM, what is the student's average speed for the trip to school?
Answer:
The student's average speed for the trip to school is 4 [tex]\frac{km}{h}[/tex]
Explanation:
Speed is a quantity that relates the displacement that an object makes in a given unit of time. In other words, speed is a physical quantity that expresses the relationship between the space traveled by an object, the time used for it and its direction.
Since the average speed relates the change in position to the time taken to effect said change, then:
[tex]speed=\frac{change in position}{time}[/tex]
In this case, the student travels a total distance of 2 km between his home and school and the total time spent on the trip is 30 minutes, then:
change in position= 2 kmtime= 30 minutes= 0.5 hours (being 60 minutes = 60 hours)Replacing:
[tex]speed=\frac{2 km}{0.5 hours}[/tex]
Solving:
speed= 4[tex]\frac{km}{hours}[/tex]
The student's average speed for the trip to school is 4 [tex]\frac{km}{h}[/tex]
A runner is jogging in a straight line at a steady vr= 8.8 km/hr. When the runner is L= 3 km from the finish line, a bird begins flying straight from the runner to the finish line at vb= 17.6 km/hr (2 times as fast as the runner). When the bird reaches the finish
Answer:
Explanation:
Speed of runner Vr = 8.8 km / h
distance to be covered = 3 km
time taken by runner to reach finish line = 3 / 8.8 h = .34 s
distance covered by the bird during this period = speed of bird x time
= 17.6 x .34 = 5.98 km .
Which of the following is not a word to describe a part of a wave?
Amplitude
Crest
Wavelength
Color
Answer:
Color, as far as I'm aware.
A car is traveling in a straight line path at a maximum speed of 7.00 m/s. The driver of the vehicle applies the brakes bringing the car to a stop after traveling 10.0 m. What is the magnitude of the car's acceleration to the nearest hundredths place?
Answer:
[tex]a=-2.45\ m/s^2[/tex]
Explanation:
An object is traveling at constant acceleration if its changes in speed are constant at the same intervals of time.
The acceleration can be calculated as follows:
[tex]\displaystyle a=\frac{v_f-v_o}{t}[/tex]
Where vo is the initial speed, vf the final speed and t is the time.
The acceleration and the distance x are related through the following equation:
[tex]v_f^2=v_o^2+2.a.x[/tex]
The car has an initial speed of vo=7 m/s when the driver stops the car (vf=0) after traveling x=10 m.
The acceleration can be calculated by solving the last equation for a:
[tex]\displaystyle a=\frac{v_f^2-v_o^2}{2x}[/tex]
[tex]\displaystyle a=\frac{0-7^2}{2*10}[/tex]
[tex]\displaystyle a=\frac{-49}{20}[/tex]
[tex]\boxed{a=-2.45\ m/s^2}[/tex]
Alisa needs to make some hot tea for her ill mother. She uses some ice-cold water from the freezer and heats it up in the kettle. As she hears the teapot whistling, she asks herself, “How is the motion of the ice water’s particles changing as the hot tea is being made?”
An automobile tire with a radius of 0.30 m starts at rest and accelerates at a constant angular acceleration of 2.0 rad/s2 for 5.0 s. What is the angular displacement of the tire?
Answer:
The value is [tex]\theta = 25 \ radian[/tex]
Explanation:
From the question we are told that
The radius is [tex]r = 0.30 \ m[/tex]
The acceleration is [tex]\alpha = 2.0 \ rad/s^2[/tex]
The time taken is [tex]t = 5.0[/tex]
Generally the angular displacement is mathematically represented as
[tex]\theta = \frac{s}{r}[/tex]
Here s is the linear distance covered by the tire which is mathematically represented as
[tex]s = u t + \frac{1}{2}a t^2[/tex]
Here u is 0 given that the car started from rest and
[tex]a = \alpha * r = 2.0 * 0.30= 0.6\ m/s^2[/tex]
So
[tex]s = 0 + \frac{1}{2}*0.6* 5^2[/tex]
[tex]s = 7.5 \ m[/tex]
So
[tex]\theta = \frac{7.5}{0.30}[/tex]
=> [tex]\theta = 25 \ radian[/tex]
The distance between pitcher and catcher on a baseball field is 18.4 m. If a pitcher releases a ball from a height of 1.5 m and the catcher catches the ball right at ground level, how fast did the pitcher throw the ball?
Answer:
33.26 m/s
Explanation:
The initial velocity of the ball can be determined by;
R = v[tex]\sqrt{\frac{2H}{g} }[/tex]
Where R is the range (distance between pitcher and catcher), H is the height covered, v is the initial velocity and g is the acceleration due gravity (9.8 m/[tex]s^{2}[/tex]).
So that;
18.4 = v[tex]\sqrt{\frac{2*1.5}{9.8} }[/tex]
= v [tex]\sqrt{\frac{3}{9.8} }[/tex]
= v [tex]\sqrt{0.3061}[/tex]
= 0.5533v
⇒ v = [tex]\frac{18.4}{0.5533}[/tex]
= 33.2550
The initial velocity of the ball is 33.26 m/s.This is the velocity with which the pitcher threw the ball.