Answer:
A) v(t) = (32 - 1.6t) m/s
a(t) = -1.6 m/s²
B) t = 20 seconds
C) 320 m
D) t = 5.85 seconds going up and 34.14 seconds going down
E) 40 seconds
Explanation:
Height is given by the equation;
S(t) = 32t - 0.8t²
A) Velocity after time t is gotten from first derivative of the distance.
Thus;
v(t) = dS/dt = 32 - 1.6t
Acceleration at time t is gotten from derivative of the velocity.
Thus;
a(t) = d²S/dt² = -1.6 m/s²
B) At highest point, velocity is zero.
Thus;
32 - 1.6t = 0
1.6t = 32
t = 32/1.6
t = 20 seconds
C) To find how high the rock goes, it means we are looking for maximum height.
This will be at t = 20 seconds.
Thus;
S(20) = 32(20) - 0.8(20)²
S(20) = 640 - 320
S(20) = 320 m
D) we want to find the time it will take to reach half its maximum height.
since maximum height is 320 m, then half the maximum height is; S_½ = 320/2 = 160
Thus;
160 = 32t - 0.8t²
0.8t² - 32t + 160 = 0
Using quadratic formula, we will get;
t = 5.85 seconds going up and 34.14 seconds going down
E) time the rock is aloft = twice the time it took to reach maximum height.
Thus; t_aloft = 2 × 20 = 40 seconds
A runner completes the 200-meter dash with a time of 19.80 seconds. What was the runner's average speed in miles per hour?
Answer:
v = 22.54 mph.
Explanation:
Given that,
Distance moved, d = 200 m
Time, t = 19.8 s
We need to find the runner's average speed.
We know that,
1 mile = 1609.34 m
200 m = 0.124 miles
19.8 seconds = 0.0055 h
So,
Speed = distance/time
[tex]v=\dfrac{0.124}{0.0055}\\\\v=22.54\ mph[/tex]
So, the runner's average speed is 22.54 mph.
What is the net power needed to change the speed of a 1600-kg sport utility vehicle from 15.0 m/s to 40.0 m/s in 4.00 seconds
Answer:
The net power needed to change the speed of the vehicle is 275,000 W
Explanation:
Given;
mass of the sport vehicle, m = 1600 kg
initial velocity of the vehicle, u = 15 m/s
final velocity of the vehicle, v = 40 m/s
time of motion, t = 4 s
The force needed to change the speed of the sport vehicle;
[tex]F = \frac{m(v-u)}{t} \\\\F = \frac{1600(40-15)}{4} \\\\F = 10,000 \ N[/tex]
The net power needed to change the speed of the vehicle is calculated as;
[tex]P_{net} = \frac{1}{2} F[u + v]\\\\P_{net} = \frac{1}{2} \times 10,000[15 + 40]\\\\P_{net} = 275,000 \ W[/tex]
The net power needed to change the speed of the vehicle is 275.000Watts
Power is the ratio of workdone with respect to the time taken.
Power = workdone/timeWorkdone = force * distance/timeWorkdone = Force * speedGet the required force:
F = m(v-u)/t
F = 1600(40-15)/4
F = 1600(25)/4
F = 400 * 25
F = 10,000N
The required net power will be calculated as shown:
P = 1/2*F(u+v)
P = 1/2(10000)*(15+40)
P = 5000(55)
P = 275,000Watts
Hence the net power needed to change the speed of the vehicle is 275.000Watts
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The driver of a car traveling at 21.6 m/s applies the brakes and undergoes a constant deceleration of 1.86 m/s 2 . How many revolutions does each tire make before the car comes to a stop, assuming that the car does not skid and that the tires have radii of 0.35 m
Answer:
each tire made 57.03 revolutions before the car halted
Explanation:
Given that;
Initial Velocity u = 21.6 m/s
final velocity v = 0 m/s
acceleration = - 1.86 m/s²
radii r = 0.35 m
first we calculate distance travelled by the car to stop;
v² - u² = 2as
s = v² - u² / 2a
we substitute
s = (0² - (21.6)² / 2 × (-1.86)
s = (0 - 466.56) / ( - 3.72 )
s = 125.419 m
Now Distance traveled by each tire in 1 revolution = 2πr
i.e 2πr is travelled in 1 revolution
so
n×2πr = 125.419 m
n = 125.419 m / 2πr
n = 125.419 m / 2π(0.35)
n = 125.419 / 0.7π
n = 57.03 revolutions
Therefore, each tire made 57.03 revolutions before the car halted
Consider a plastic rod that is being charged up by rubbing a wool cloth. It is then brought to an initially neutral metallic sphere, and allowed to touch the sphere for a few seconds. The rod is then separated from the sphere by a small distance. After becoming separated, the rod:________.
A) is repelled by the sphere.B) is attracted to the sphere.C) feels no force due to the sphere.
Answer:
A) is repelled by the sphere
Explanation:
When a piece of plastic is rubbed with a wooden cloth, it sinks negativelyLet it change Q. So it is now allowed to touch the neutral zone. Therefore, there is a difference in the surface capacity of the two bodies, so that charge transfer takes placeSome of its negative charge is transferred to the metal sphere, now both the rod and the sphere are negatively charged and the same chargers as we know are repelled by each other.so correct answer is A) is repelled by sphereA student drives the 105-mi trip back to campus after spring break and travels with an average speed of 53 mi/h for 1 hour and 30 minutes for the first part of the trip. (a) What distance was traveled during this time?
Answer:
79.5 miles.
Explanation:
From the question given above, the following data were obtained:
Average speed = 53 mi/h
Time = 1 hr 30 minutes
Distance travelled =?
Next, we shall convert 1 hr 30 minutes to hours. This can be obtained as follow:
Recall:
1 hr = 60 mins
Therefore,
1 hr 30 mins = 60 + 30 = 90 minutes.
60 mins = 1 hr
Therefore,
90 mins = 90 mins × 1 hr / 60 mins
90 mins = 1.5 hr
Finally, we shall determine the distance travelled during the time. This can be obtained as follow:
Average speed = 53 mi/h
Time = 1.5 hr
Distance travelled =?
Average speed = Distance travelled / time
53 = Distance travelled / 1.5
Cross multiply
Distance travelled = 53 × 1.5
Distance travelled = 79.5 miles
6. A baseball player hits a 0.155-kilogram fastball traveling at -44.0 m/s into center field at a speed of 50.0
m/s. If the impact lasts for 0.00450 second, with what force does he hit the
baseball?
Answer:
3,237.78N
Explanation:
According to Newton's second law of motion
F = mass * acceleration
Since a = v-u/t
F = m(v-u)/t
Given
Mass m = 0.155kg
v = 50.0m/s
u = -44.0m/s
Time t = 0.00450secs
Substitute
F = 0.155(50-(-44))/0.00450
F = 0.155(50+44)/0.00450
F = 0.155(94)/0.00450
F = 14.57/0.00450
F = 3,237.78N
hence he hit the baseball with a force of 3,237.78N
Which would have more kinetic energy a dog walking or the same dog running?
Answer:
dog walking
Explanation:
a student that just received their driver's license decides to buy a new car. he remembers from physics class that heat engines have thermal efficiency that can be calculated. he asks the car dealer for a car that has a high thermal efficiency rating. the car dealer say he has a car that is 100% efficient. which law of thermodynamics best describes why the car cannot be 100% efficient?
Answer: the first law of thermodynamics
Explanation:
The second law of thermodynamics is the best description for the car to cannot be having 100% efficient engine.
What is the second law of thermodynamics?Thermodynamics is the branch of science which deals with the study of heat. Heat is a form of energy which exists as a result of the change in the temperature between the two bodies or objects under study.
The second law of thermodynamics is a physical law, which is based up on the universal experience concerning with the heat and energy interconversions between bodies present in the system and surrounding. One simple statement of this law is that, the heat energy always moves from the hotter objects to the colder objects, unless the energy in some form is supplied to the object to reverse the direction of heat flow between the objects.
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1pt If the room is the frame of reference for the study of an object moving in three dimensions, from where should distances be measured?
O A. one wall and the floor
OB. two walls and the floor
O c. the floor and the ceiling
O D. the door
Answer:
Option B, two walls and the floor
Explanation:
The distance should be measured from the point where at least the three axed meet.
Two walls and the floor are equivalent to three axes.
Vertical wall 1 = Y Axis
Horizontal wall2 = X Axis
Floor = Z Axis
Thus, the distance should be measured from the point where two walls and one floor meet.
Option , B is correct
A car traveling at 55 MPH North is an example velocity vector.
O True
O False
Answer:
false
Explanation:
a ball is thrown upward with a beginning speed of 40m/s. The graph below shows how the speed of the ball changes until it reaches its maximum height.
use the graph to find
a) the time when the ball reaches its maximum height
b) the acceleration of the ball
c) the maximum height the ball went
Answer:
a) 4.0816s
b) -9.8 ms^-1
c) 81.63265m
A particle moving in the xy-plane has velocity v⃗ =(2ti^+(3−t2)j^)m/s, where t is in s.
Part A
What is the x component of the particle's acceleration vector at t = 6 s?
Express your answer with the appropriate units.
Part B
What is the y component of the particle's acceleration vector at t = 6 s?
Express your answer with the appropriate units.
Answer:
A) 2 m/s²
B) -12 m/s²
Explanation:
A)
Applying the definition of instantaneous acceleration as the derivative of the velocity with respect to time, the acceleration vector can be expressed as follows:a = 2i^ + (-2t) j^ m/s²So, the x-component of the acceleration vector is constant, and equal to 2m/s², at any time.When t=6 s, aₓ= 2 m/s²B)
Applying the definition of instantaneous acceleration as the derivative of the velocity with respect to time, the acceleration vector can be expressed as follows:a = 2i^ + (-2t) j^ m/s²So, when t= 6s, the y component of a is as follows:ay = -2(6s) = -12 m/s²A) The x-component of the particle's acceleration is; 2 m/s²
B) The y-component of the particle's acceleration at t = 6 is; -12 m/s²
X and Y components of Acceleration
We are given the velocity as;
v^ = 2t i^ + (3 − t²) j^ m/s
A) We know that acceleration is simply a derivative of velocity with respect to time. Thus;
a^ = dv/dt = 2 i^ + (-2t) j^ m/s²
The x - component of the acceleration is the figure attached to the vector i^.
Thus, x-component of acceleration = 2 m/s²
B) The y-component of the acceleration will be the value attached to the vector j^. Thus;
y-component of acceleration = -2t m/s²
At t = 6 s, we have;
y-component of acceleration = -2(6) = -12 m/s²
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A crane is used to lower weights into a lake for an underwater construction project. Determine the tension in the cable of the crane due to a concrete sphere with a radius of 2 m when the sphere is lowered into the water. The concrete has a specific gravity of 2.8.
Answer:
Tension in the cable = 591292.8 N or 591.3 kN
Explanation:
Tension in the cable = Weight of object in air - upthrust/bouyancy due to the liquid
Weight of object in air = mass * acceleration due to gravity, g
Since mass is not given, it is obtained from the formula, mass = density * volume
Volume of the sphere = 4/3πr³ where r, radius = 2 m; π = 22/7
volume = 4/3 * 22/7 * (2m)³
volume of sphere = 33.52 m³
Density of concrete sphere = specific gravity * density of water
where, specific gravity = 2.8, density of water = 1000 kg/m³
density of concrete = 2.8 * 1000 kg/m³
density of concrete = 2800 kg/m³
acceleration due to gravity, g = 9.8 m/s²
Thus, weight of concrete = 2800 kg/m³ * 33.52 m³ * 9.8 m/s² = 919788.8 N
Upthrust = density of water * volume of sphere * g
Upthrust = 1000 kg/m³ * 33.52 m³ * 9.8 m/s² = 328496 N
The tension in the cable is the calculated as below;
Tension in the cable = Weight of object in air - upthrust/bouyancy due to the liquid
Tension in cable = 919788.8 N - 328.496 N = 591292.8 N
Therefore, tension in the cable is 591292.8 N or 591.3 kN
An offshore oil platform houses a drill for drilling oil. The drill descends from the platform and enters the ocean. At the bottom of the ocean, the drill starts to dig into the rock. It continues drilling into the rock for another 7,000 feet and then stops. Where does the drill stop?
Answer:
Geosphere
Explanation:
I did it and got the answer right.
Answer:
in the geosphere
Explanation:
Secondly, a man is rock climbing when suddenly the rock face he grabs breaks away and he is left with a 1200 lb. rock on his chest. How do scientists say he was able to lift this incredible weight and save himself
Answer:
rush of adrenaline
Explanation:
This is believed to have been possible due to the rush of adrenaline that the individual was experiencing. This has happened a couple times in moments of extreme distress where an individual's body is flooded with adrenaline. This adrenaline allows for super human like strength as well as increased senses. The individual that has lifted the most amount of weight in such a scenario, lifted a total of 3000 lbs. Therefore, it is fair to say that 1200 lb. rock was lifted due to adrenaline.
what are the four intermittent reinforcement schedules in your own words?
A 0.20 kg mass is oscillating on Planet X at a small angle from a light string of length 0.15 m with a period of
0.75 s.
What is the acceleration of gravity on Planet X?
Round answer to two significant digits.
Answer:
11 m/s^2
Explanation:
We can determine the acceleration of gravity from the pendulum’s period and length.
Let’s use the equation for the period of a pendulum and solve for the acceleration of gravity:
A copper atom has an atomic number of 29 and an atomic mass of 64. What is the structure of this atom?
A. It has a central nucleus composed of 29 protons and 35 neutrons,
surrounded by an electron cloud containing 29 electrons.
B. It has a central nucleus composed of 29 protons and 64 neutrons,
surrounded by an electron cloud containing 29 electrons.
C. It has a central nucleus composed of 35 protons and 29 neutrons,
surrounded by an electron cloud containing 29 electrons.
D. It has a central nucleus composed of 29 protons and 29 neutrons,
surrounded by an electron cloud containing 35 electrons.
Answer:
Explanation:
Atomic mass is nuetrons + protons.
Basically it's
? nuetrons + protons = 64
I did process of elimination:
b) It cannot be "b" because 29 + 64 doesn't equal 64.
c) It cannot be "c" because in a regular molecule the amount of protons equals to amount of electron(s).
d) 29 + 29 doesn't = 64.
Therefore, the answer is "A"
Answer: A
Explanation: Just took the test on a.pex
At 10 seconds, you used 55 Joules. Can you tell me the power?
Answer:
5.5
Explanation:
power =energy÷time
power=55÷10
power=5.5
A woman is reported to have fallen 144 ft from the 17th floor of a building, landing on a metal ventilator box that she crushed to a depth of 18.0 in. She suffered only minor injuries. Ignoring air resistance, calculate
A) The speed of the woman just before she collided with the ventilator.
B) Her average acceleration while in contact with the box.
C) Modeling her acceleration as constant, calculate the time interval it took to crush the box.
Answer:
Okay uh gimme some time though
Two trucks are traveling east on I-40 when the Walmart truck (61 mph, 57 ft long) decides to pass the FedEx truck (53 mph, 60 ft long). A 'pass' starts when the front of the Walmart truck is 45 ft behind the rear of the FedEx truck and ends when the rear of the Walmart truck is 45 ft in front of the front of the FedEx truck.
How long does it take for the Walmart truck to pass the FedEx truck?
How far does the Walmart truck travel while passing the FedEx truck?
Answer:
The answer is below
Explanation:
Let us assume that the slower truck which is the FedEx truck travels d mile. The pass started when the Walmart truck was 45 ft behind the FedEx truck and ended when the Walmart truck is 45 ft in front of the FedEx truck.
The additional distance covered by the truck Walmart = 45 ft + 60 ft (length of FedEx truck) + 45 ft = 150 ft
1 mile = 5280 ft
150 ft = 150 ft * 1 mile/5280 ft = 0.0284 mile
Therefore the Walmart truck covered an additional 0.0284 mile. Hence the distance covered by the walmart truck = d + 0.0284
Let us say it took t hours for the pass to be completed. Hence:
For FedEx; 53 mph = d / t. t =d / 53
For Walmart; 61 mph = (d + 0.0284) / t. t = (d + 0.0284) / 61
Since it took the trucks the same time. Hence:
d / 53 = (d + 0.0284) / 61
61d = 53d + 1.506
8d = 1.506
d = 1.506/8
d = 0.1882 mile = 993.75 ft
The FedEx truck traveled 993.75 mile while the Walmart truck traveled 1143.75 ft (993.75 + 150 ft)
The time (t) = d / 53 = 0.1882 / 53
t=0.00355 h = 12.8 seconds
Using the graph, when (in seconds) would you expect the object to have the highest velocity? Explain your answer.
Answer:
blue
Explanation:
nswer the following about two objects, A and B, whose motion produced ihe following ... "A" starts with a greater (t) position. Since they ... since you are moving away from the origin
Sort the following properties as quantitative or qualitative property MASS-DENSITY-VOLUME-MELTING POINT
Answer:
mass, volume: quantitative propereties: extensive properties
volume, melting point: quantitative propereties: intensive properties
Explanation:
The quantitative properties of matter are characteristics of matter that can be measured and of which quantities can be expressed.
Quantitative properties can be divided into 2 groups:
Extensive properties: This is whose value depends on the amount of substance analyzed. They are not properties that allow us to distinguish one substance from another, since its value changes depending on the size of the object or sample that you have. Intensive properties: are those that do not depend on the mass or size of a body. That is, these are properties whose value is independent of the amount of substance analyzed; they are useful for differentiating substances.On the other hand, the qualitative properties of matter are those that cannot be expressed in numerical values or quantities. They are detected, in many cases, through the senses, since they do not measure them.
In this case:
mass, volume: quantitative propereties: extensive propertiesvolume, melting point: quantitative propereties: intensive propertiesWhat recreational drug does an alcopop contain?
An "alcopop" is a term used to describe a flavored alcoholic beverage that typically resembles a soft drink or a fruit juice in appearance and taste. It is also referred to as a "ready-to-drink" (RTD) beverage.
Alcopops are often targeted toward younger consumers and are known for their sweet and fruity flavors, which can mask the taste of alcohol.
The specific recreational drug that an alcopop contains is alcohol itself. Alcohol, or ethanol, is a psychoactive substance that can have intoxicating effects when consumed.
It is considered a recreational drug because of its ability to alter consciousness, impair judgment and coordination, and produce pleasurable or mood-altering effects.
The alcohol content in alcopops can vary, but it is typically lower than in pure spirits or liquors. This is often achieved through dilution with other ingredients, such as carbonated water or fruit juices, to create a milder alcoholic beverage.
Alcopops may also contain additional flavorings, sweeteners, and additives to enhance their taste and appeal.
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Points A, B, and C lie along a line from left to right, respectively. Point B is at a lower electric potential than point A. Point C is at a lower electric potential than point B. What would best describes the subsequent motion, if any, of a positively-charged particle released from rest at point B?
Answer:
Please see below as the answer is self-explanatory.
Explanation:
If the potential at B is lower than A, and the potential at C is lower than B, this means that there is an electric field, directed from A to C.If a positively-charged particle is released at rest at point B, it will be accelerated by the electric field (which is a force per unit charge, so it produces an acceleration) in the same direction than the field (because it is a positive charge) towards point C.Anastasia constructed a simple circuit with a battery and a light bulb. She knows that the resistance of the light bulb is 10
2 and that the voltage given to the light bulb is 12 V. What is the current through the light bulb?
Answer:
Simple Single Loop Circuits. J. E σ. = ∆V = IR ... To find the current, use the total voltage and equivalent resistance: S. V ... A circuit contains a 48-V battery and two 240Ω light bulbs.
Help please ............
Answer:
Explanation:
Electrical current is the movement of charge. The units are Amperes (Amps)
36.0 g of water is to be heated through a temperature change of 9.00 C. How much energy will be required?
36.0 g water is to be heated through a
As per specific heat capacity ,42,638 J/Kg°C energy is required to raise the temperature by 9°C.
What is specific heat capacity?Specific heat capacity is defined as the amount of energy required to raise the temperature of one gram of substance by one degree Celsius. It has units of calories or joules per gram per degree Celsius.
It varies with temperature and is different for each state of matter. Water in the liquid form has the highest specific heat capacity among all common substances .Specific heat capacity of a substance is infinite as it undergoes phase transition ,it is highest for gases and can rise if the gas is allowed to expand.
It is given by the formula ,
Q=mcΔT
For the given question, it is calculated by substituting the values in the given formula,
Q=30×4.2×282
=42,638 J/Kg°C
Thus, 42,638 J/Kg°C of energy is required for raising the temperature by 9°C.
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pls help ;-; this is the question btw
The answer is "Infrared"
Hope this helps
Answer:
x-rays
Explanation:
What is the frequency of this wave
1
2
3
4
Answer: The answer is 2
Explanation:
I got it wrong by picking 3 and the correct option was 2 on edge