In the lab, a student is investigating the effects of texting and driving on reaction time. A
student determines his/her reaction time by having a friend release a meter stick at
random intervals while the driver sends text messages. The student, on average,
catches the meter stick after it has traveled 0.64 m.
How far will the student
travel in a car moving at 25 m/s horizontally before reacting?
9.0 m
0.64 m
69 m
We know that we can write the speed of something as the quotient between the distance it moves and the time it takes to move that distance.
speed = distance/time
Using this, we will find that the correct option is the first one, 9.0 m
The information we know is:
The student, on average, catches the meter stick after it has traveled 0.64m
We need to transform this into time.
Assuming that the meter stick is just released, the only acceleration it will have is the gravitational one, so we have:
a(t) = -9.8m/s^2
To get the velocity of the stick we need to integrate over time, as the it is just released, it will not have initial velocity, thus the constant of integration is zero:
v(t) = (-9.8m/s^2)*t
To get the position equation we need to integrate again, and as the initial position is relative, we can define it as zero, so again the constant of integration is zero:
p(t) = (1/2)(-9.8m/s^2)*t^2
p(t) = (-4.9 m/s^2)*t
We know that the student catches the stick after it traveled (downwards) 0.64m
Then we need to solve:
-0.64m = (-4.9 m/s^2)*t
√[(-0.64m)/(-4.9m/s^2)] = t = 0.36s
So the reaction time of the student is 0.36 seconds.
Now we can use the first equation:
speed = distance/time
And rewrite it as:
distance = speed*time
So if the car moves at 25m/s and the student needs 0.36 s to react, the distance that he/she will move in that time frame is:
d = (25m/s)*0.36s = 9.0m
So the correct option is the first one.
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how do you find displacement
Answer:
Displacement can be calculated by measuring the final distance away from a point, and then subtracting the initial distance. Displacement is key when determining velocity (which is also a vector). Velocity = displacement/time whereas speed is distance/time. I hope it helped. Please give brainliest
Explanation:
Consider a box sliding down horizontally across a straight line. Which of the following factors affects the amount of work done against friction in this situation?
A. Speed of the box
B. Time taken to move the box
C. Distance the box is moved
D. Direction of the box is moved
Answer:
uhhh speed of box??? I think
The factor affecting the amount of work done against friction is the distance traveled by the box.
The work done against friction is energy dissipated in reducing frictional force along the horizontal surface.
The magnitude of the work done in reducing the frictional force along the horizontal surface is given as;
W = μFd
where;
μ is the coefficient of frictionF is applied horizontal forced is the horizontal distance traveled by the boxThus, we can conclude that the factor affecting the amount of work done against friction is the distance traveled by the box.
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What happens to potential energy as the mass of an object decreases?
Answer:
As the mass of the object decreaes, the potential energy also decreases.
Explanation:
5. A vehicle having a mass of 1000 kg had an accident on a wet, but level, concrete road under foggy
conditions. The tires were measured to have y = 0.55 on wet concrete. The driver locked the
brakes, skidded for 6 seconds, and then hit the guardrail causing a very small dent because the
vehicle stopped just as it touched the guardrail. The driver claimed to be driving 65 miles per hour
(29 m/s). You have been hired as an investigator to determine if the driver is telling the truth.
a. What is the weight of the vehicle?
b. The frictional force produces the negative acceleration that reduces the velocity of the
vehicle from its initial unknown speed to zero. Find the value of the frictional force.
Use the frictional force to calculate the acceleration (remember that it is a negative
number). Hint: Use Newton's 2nd Law.
d. Using your acceleration from partc, what was the driver's initial velocity? Hint: Use this
equation - The final velocity is 0 m/s.
6. Complete this form to let me know what your questions are. This helps me get you the help you
need - either during class or individually through videos
Answer:
Explanation:
1) weight = mg = 9.81*1000 = 9810 Newtons
2) frictional force = normal force *
we must assume that the vehicle is on a flat surface so therefore the normal force is the same as the weight of the vehicle.
frictional force = 9810 * 0.55 = 5 395.5 N
3) acceleration: F = ma, a = F/m
assume that only the frictional force is acting on the vehicle:
a = 5395.5/1000 = 5.3955 m/s
4) the car decelerates at 5.3955m/s
over 6 seconds, the car decelerates by: 32.37m/s
5) original speed = 29m/s final speed = 29-32.37 = -3.37m/s which is a negative number, therefore the vehicle would have stopped before it hit the rail.
6) to get to the rail, the vehicle would have had to be traveling at least 32.37m/s which is 72.41 mph
PLS HELP!!!- The moon rotates around the Earth every 28 days. What is the frequency of the moon’s revolution?
Answer: the frequency is every 27.322 days
2. Who was the first woman to dunk in a professional basketball game?
Answer: Lisa Leslie
Explanation: On July 30, 2002, Leslie became the first woman to dunk the ball in a WNBA game.
Answer:
Lisa Leslie
Explanation:
On July 30, 2002, Leslie became the first woman to dunk the ball in a WNBA game
non-example of Newton's third law of motion
Answer:
Unbalanced forces
Explanation:
a nucleus with four protons have a total positive charge of what
Answer:
The name of element is Beryllium.
Explanation:
Given that,
A nucleus with four protons have a total positive charge.
Suppose, what is the name of element ?
We know that,
The name of element which have 4 positive charge is Beryllium.
Beryllium is a element which is symbol is Be.
Atomic number of beryllium is 4 and atomic mass is 9.
The number of neutrons are 5.
Hence, The name of element is Beryllium.
my little cousin wanted me to ask this so, How does thermal energy travel to Earth?
Heat moves in three ways: Radiation, conduction, and convection. Radiation happens when heat moves as energy waves, called infrared waves, directly from its source to something else. This is how the heat from the Sun gets to Earth. In fact, all hot things radiate heat to cooler things.
Chlorine has 17 electrons. According to the modern atomic theory, how many electrons are found in n = 2?
Answer:
8 electrons
Explanation:
According to the modern atomic theory, the electronic configuration of chlorine (e⁻ = 17, Z = 17) is:
1 s² → 2 electrons
2 s² 2 p⁶ → 8 electrons
3 s² 3 p⁵ → 7 electrons
Total: 17 electrons
In n = 1 chlorine has 2 electrons, in n = 2 chlorine has 8 electrons and in n = 3 it has 7 electrons.
Therefore, in n = 2 chlorine has 8 electrons (2 from s orbital and 6 from p orbital).
I hope it helps you!
Which of the following is NOT an acceleration?
O Riding your bike faster when you head down a hill
Slowing your bike so you can make it up a hill
O Coming to a stop at an intersection
Riding down the street at a constant velocity
Answer:
coming to stop at intersecton
Explanation do u not know what acceleration is?
Two persons A and B are walking with the speed of 5km/h and 6km/h respectively in the same direction. Find how far will B be from A after 2 hours??
Answer:2 km
Explanation:
If you travel 10 miles, how many kilometers are traveling
Answer:
16.0934
Explanation:
Miles to kilometers
what cells secrete myelin for neurons?
a. schwann cells
b. other neurons
c. osteocytes
d. leukocytes
Answer:
A. Schwann cells
Explanation:
PLEASE HELP AND HURRRRY
A package is dropped from a plane flying at a constant speed. Neglecting air resistance, when the package hits the ground the horizontal location of the plane will....
A. Be behind the package
B. Depend on speed of package
C. Be directly over the package
D. Be in front of the package
Answer:
A. Be behind the package
Which of these chemical properties of a sheet of paper
Answer:
Paper is created mainly from organic compounds such as oxygen, carbon, hydrogen. Paper has non-organic compounds also for improving the properties.
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First to answer.
A boat sends a sound to the bottom of the ocean and it takes 3 seconds to return to the boat. How deep in the ocean? The speed of sound on water is 1500m/s.
Answer:
2,250 meters deep
Explanation:
If the time taken for the the signal to return to the boat means that it took 3 seconds for the signal to travel to and from the floor the same distance. That means it took 1.5 seconds to travel to the floor at a speed of 1500m/s means that it is 1500 multiplied by 1.5 to a distance of 2,250m. (Derived from the speed = distance divided by time formula to distance = speed multipled by time)
Who is Josh Gibson write a short paragraph 3-5 sentences
Answer:
Hope this helps
Explanation:
Josh Gibson, (born December 21, 1911, Buena Vista, Georgia, U.S.—died January 20, 1947, Pittsburgh, Pennsylvania), American professional baseball catcher who was one of the most prodigious home run hitters in the game’s history. Known as “the black Babe Ruth,” Gibson is considered to be the greatest player who never played in the major leagues, there being an unwritten rule (enforced until the year of his death) against hiring black ballplayers
Which person has the most kinetic energy?
O A. A person sitting in a chair
OB. A person sitting at the top of a slide
O C. A person riding a bicycle
O D. A person walking
A person riding a bicycle has the most kinetic energy among the given options, therefore the correct option is C.
What is mechanical energy?Mechanical energy is the combination of all the energy in motion represented by total kinetic energy and the total stored energy in the system which is represented by total potential energy.
The expression for total mechanical energy is as follows
ME= PE+KE
Where ME is the mechanical energy
PE is the total potential energy
KE is the total kinetic energy
The kinetic energy is the body depends on the mass as well as the speed of the object and is given by the mathematical expression as follows
K.E = 1/2*m*v²
where K.E is the kinetic energy of the object
m is the mass of the object
v is the velocity of the object
For the given problem and the options provided for the person riding the bicycle has the most kinetic energy among all, therefore the correct option is C.
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You are in a car moving at 50 mph to the right, from the reference frame of the ground. A truck is next to you moving at 30 mph to the right, also from the reference frame of the ground. Which is true from your reference frame of the car?
a. The truck would appear to stand still.This answer is incorrect.
b. The truck would appear to be moving forward.
c. The truck would appear to be moving backward.
Who was the first person to walk on the moon ?
Answer:
god correct correct
Explanation:
How long does it take a cyclist to increase his velocity from 4.0m/s to 10m/s if he accelerates at 3.0m/s2
Hydrogen is found as a gas on Earth but exists in all four states in the solar
system. Four samples of hydrogen have equal masses but are each in a
different state. Which statement about the relative amounts of thermal
energy in the samples is true?
Answer: the sample of solid has less energy than the sample of gas
Explanation:
APEX
Johnny often hits his brother even though his brother does not do anything to the tag and eyes assume Johnny aggression is more like most likely due to a combination of
when maggie applies the brake of her car, the car slows
Help please asap!!!!
Answer:
Line A is fastest and Line D is slowest
Explanation:
Line A is the fastest moving object because the bar is steepest. Line A travelled the furthest in the least time, so Line A is moving fastest. Line D is the slowest object because the bar is least steep. Line D travelled the least distance in the most time, so Line D moves the slowest.
Hopefully the answer and explanation helps!
Spring A has a spring constant of 5 N/m and spring B has a force constant of 9 N/m. A weight of 2 kg is applied to spring A and a weight of 10 kg is applied to spring B. Which of the following is true for the final displacements of springs A and B?
a) Spring B has a larger displacement than spring A. b) Spring A has a larger displacement than spring B. c) Spring A and spring B have the same displacement.
Answer: Option A.
Spring B has a larger displacement that spring A.
Explanation:
Spring B has a larger displacement that spring A .
By using Hooke's law.
F=-Kx
Where F is force, K is spring constant and x is displacement.
For spring a
Weight / force is 2 kg
Spring constant (K) is 5/nm
Therefore,
F=-Kx
2=-5x
X=2/-5
X= -0.4m
For spring B.
Weight is 10Kg
Spring constant is 9N/m
F=-Kx
10=-9x
X=-10/9
=-1.1m
Therefore Spring B have larger displacement than spring A.
In Hooke's law, negative sign that is present on the spring's force indicate that the force exerted by the spring opposes the spring's displacement.
Help!!
Earth has a radius R = 1.5 x 1011 m, T= 365.3 days, and m= 5.97 x 1024 kg. Calculate the
speed of Earth around the sun, assuming a circular orbit.
Answer:
[tex]29861.23\ \text{m/s}[/tex]
Explanation:
[tex]R=\text{Radius of Earth's orbit}=1.5\times10^{11}\ \text{m}[/tex]
[tex]T=\text{Time taken by the Earth to complete the orbit}=365.3\ \text{days}[/tex]
Assuming the orbit is of circular shape the distance the Earth has to travel is the circumference
[tex]C=2\pi R\\\Rightarrow C=2\pi\times 1.5\times10^{11}\\\Rightarrow C=942477796076.938\ \text{m}[/tex]
Velocity is given by
[tex]v=\dfrac{C}{T}\\\Rightarrow v=\dfrac{942477796076.938}{365.3\times 24\times 60\times 60}\\\Rightarrow v=29861.23\ \text{m/s}[/tex]
The speed of the Earth around the Sun is [tex]29861.23\ \text{m/s}[/tex]
1. Who were the first three countries to build rocket engines?
O Russia, Germany, China
O Germany, China, Canada
O Russia, USA, Germany
O USA. China, Russia
Answer:
i think its Russia, USA, Germany.