a place-kicker must kick a football from a point 36.0 m (about 40 yards) from the goal. half the crowd hopes the ball will clear the crossbar, which is 3.05 m high. when kicked, the ball leaves the ground with a speed of 23.9 m/s at an angle of 51.5 degrees to the horizontal. (a) by how much does the ball clear or fall short of clearing the crossbar?
(b) does the ball approach the crossbar while still rising or while falling?
Explanation:
Let's calculate the components of the football's velocity:
[tex]v_{0x} = (23.9\:\text{m/s})\cos{51.5°} = 14.9\:\text{m/s}[/tex]
[tex]v_{0y} = (23.9\:\text{m/s})\sin{51.5°} = 18.7\:\text{m/s}[/tex]
a) The time it takes for the football to travel 36.0 m horizontally is
[tex]t = \dfrac{x}{v_{0x}} = \dfrac{36.0\:\text{m}}{14.9\:\text{m/s}} = 2.4\:\text{s}[/tex]
During this time, the y-displacement of the football is
[tex]y = v_{0x}t - \frac{1}{2}gt^2[/tex]
[tex]\:\:\:\:= (18.7\:\text{m/s})(2.4\:\text{s}) - \frac{1}{2}(9.8\:\text{m/s}^2)(2.4\:\text{s})^2[/tex]
[tex]\:\:\:\:= 16.7\:\text{m}[/tex]
This means that the football cleared the crossbar by 16.7 m - 3.05 m = 13.7 m
b) To determine whether the football was rising or falling while clearing the crossbar, let's look at the y-component of its velocity after 2.4 s:
[tex]v_y = v_{0y} - gt = 18.7\:\text{m/s} - (9.8\:\text{m/s}^2)(2.4\:\text{s})[/tex]
[tex]\:\:\:\:\:\:= -4.82\:\text{s}[/tex]
Since its sign is negative, this means that the football was already on its way down.
Consider the frame shown in (Figure 1). The suspended cylinder has a mass of 90 kg .
Determine the x and y components of reaction at pin B on BC using scalar notation.
Determine the x and y components of force at pin C using scalar notation.
A system in equilibrium has a moment sum of zero and the sum of upward
forces equal to the sum of the downward forces.
The correct values are;
The x and y component of the reaction at pin B are;
Bₓ = 1471.5 N
[tex]B_y[/tex] = 1103.625 N
The x and y component of the force at pin C are;
Cₓ = 588.6 N
[tex]C_y[/tex] = 220.725 N
Reasons:
The weight of the cylinder, W = 90 kg × 9.81 m/s² = 882.9 N
Considering member AB, gives;
[tex]\sum M_A[/tex] = [tex]B_y[/tex] × 2 - [tex]B_x[/tex] × 1.5 = 0 ⇒ [tex]B_y[/tex] = 0.75·Bₓ
Considering member CB, gives;
[tex]\mathbf{\sum M_C}[/tex] = -[tex]B_y[/tex] × 2 + 882.9 × 2.5 = 0 ⇒ [tex]B_y = \dfrac{882.9 \times 2.5}{2} = 1103.625[/tex]
[tex]B_y[/tex] = 0.75·Bₓ ⇒ [tex]B_x = \dfrac{B_y}{0.75} = \dfrac{1103.625}{0.75} = 1471.5[/tex]
The x and y component of the reaction at pin B are;
Bₓ = 1471.5 N, [tex]B_y[/tex] = 1103.625 N
[tex]\mathbf{\sum F_y}[/tex] = 0 ⇒ -[tex]C_y[/tex] + [tex]B_y[/tex] - 882.9 = 0 ⇒ [tex]-C_y[/tex] + 1103.625 - 882.9 = 0
[tex]C_y[/tex] = 1103.625 - 882.9 = 220.725
[tex]\sum F_x[/tex] = 0 ⇒ -Cₓ + Bₓ - 882.9 = 0 ⇒ -Cₓ + 1471.5 - 882.9 = 0
Cₓ = 588.6
The x and y component of the reaction at pin C are;
Cₓ = 588.6 N, and [tex]C_y[/tex] = 220.725 N
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Atoms of which two elements could combine with atoms of carbon (C) to
form covalent bonds?
A. S
B. Na
C. N
D. K
E. Ca
Answer:
Correct answer is letter E.Ca
Bill is sitting on a tree limb that is 4 meters above the ground with a water balloon. He wants to drop the water balloon so that it falls on his friend Tim who is approaching on a bike at a constant speed of 8 meters per second. How far away should Tim be from a point directly under bill when bill drops the balloon?
Answer:
wow poor bill
Explanation:
The surface of a running track is made of rubber. A heavy trolley is pulled on to the track and it exerts a large force on the rubber track. State two effects that this force has on the rubber
Answer:
hi im from canada so can we be friends
A cabinet weighs 98N. What is the mass of the cabinet in kilogram?
Note: No need to write the units in your answer. Just the number only.
Write your solution and answer with units in your science portfolio.
Formulas: m=w/g: or w=mg
Answer:
the answer to ur questioj is 10 kg
11. A plow pushes 100 kg of snow with 300 N of force. How much is the pile of snow
accelerated?
Answer:
Explanation:
This is an application of Newton's second Law.
Formula
F = m * a
F = 300 N
m = 100 kg
a = ?
F = m * a
300N = 100 kg * a Divide by 100
300N/100kg = a
a = 3 m/sec^2
A player kicks a soccer ball.
What is the reaction force?
A. The ball pushes back on the player's
foot.
B. The ground pushes back on the player.
C. The ground pushes back on the ball.
Answer:
the ground pushes back on the player
Answer:
c
Explanation:
force is every where so anything that goes up must come down
what is one measurement needed to calculate the speed of an object
Answer:
The equation for speed is simple: distance divided by time. You take the distance traveled (for example 3 meters), and divide it by the time (three seconds) to get the speed (one meter per second).
Explanation:
Which factors would increase heating of Earth, and which factors would decrease it
Answer:
So as sunlight continued to enter the box and the walls continued to warm, heat built up inside and increased the temperature.
I WILL MARK BRAINLIEST !! PLEASE HELP!
Answer:
b
Explanation:
The pulley shown in the attached diagram has a diameter of 30 centimeters and a mass of 19 kilograms. The pulley is a solid disk with an axle through its center.
(a.) What is the moment of inertia of the pulley?
(b.) What is the magnitude of the net torque on the pulley about its axis
(c.) What is the direction of the net torque on the pulley?
(d.) What is the magnitude of the angular acceleration of the pulley?
(e.) What is direction of the angular acceleration?
Answer:
Explanation:
a) I = ½mR² = ½(19)(0.15²) = 0.21375 kg•m²
b) τ = Fnet(r) = (25 - 12)(0.15) = 1.95 N•m
c) CCW
d) a = τ/I = 1.95 / 0.21375 = 9.12280701... = 9.1 rad/s²
e) CCW
2. a) A disc rotates about its axis at speed 25 revolutions per minute and takes 15 s to stop. Calculate the
i) angular acceleration of the disc.
ii) number of rotation of the dise makes before it stops.
The statement shows a case of rotational motion, in which the disc decelerates at constant rate.
i) The angular acceleration of the disc ([tex]\alpha[/tex]), in revolutions per square second, is found by the following kinematic formula:
[tex]\alpha = \frac{\omega_{f}-\omega_{o}}{t}[/tex] (1)
Where:
[tex]\omega_{o}[/tex] - Initial angular speed, in revolutions per second.[tex]\omega_{f}[/tex] - Final angular speed, in revolutions per second. [tex]t[/tex] - Time, in seconds.If we know that [tex]\omega_{o} = \frac{5}{12}\,\frac{rev}{s}[/tex], [tex]\omega_{f} = 0\,\frac{rev}{s}[/tex] y [tex]t = 15\,s[/tex], then the angular acceleration of the disc is:
[tex]\alpha = \frac{0\,\frac{rev}{s}-\frac{5}{12}\,\frac{rev}{s}}{15\,s}[/tex]
[tex]\alpha = -\frac{1}{36}\,\frac{rev}{s^{2}}[/tex]
The angular acceleration of the disc is [tex]\frac{1}{36}[/tex] radians per square second.
ii) The number of rotations that the disk makes before it stops ([tex]\Delta \theta[/tex]), in revolutions, is determined by the following formula:
[tex]\Delta \theta = \frac{\omega_{f}^{2}-\omega_{o}^{2}}{2\cdot \alpha}[/tex] (2)
If we know that [tex]\omega_{o} = \frac{5}{12}\,\frac{rev}{s}[/tex], [tex]\omega_{f} = 0\,\frac{rev}{s}[/tex] y [tex]\alpha = -\frac{1}{36}\,\frac{rev}{s^{2}}[/tex], then the number of rotations done by the disc is:
[tex]\Delta \theta = 3.125\,rev[/tex]
The disc makes 3.125 revolutions before it stops.
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Give two examples of contact and non-contact forces and explain why they are contact and non-contact forces respectively.
The Two examples of contact forces are:
frictional force Contact force.The two examples of non contact forces are:
Gravitational forcemagnetic force.Contact forces happens due to the contact between two objects
Non Contact forces happens because there is no contact between two objects. There is no attraction.
An instructor gives a demonstration in which he makes a standing wave on a long thin slinky. The slinky is 6.0 meters long. If you see 3 loops on the slinky when the instructor shakes the end of the slinky at a rate of 2.50 cycles per second, then the speed (in m/s) of transverse traveling waves on the slinky is
The characteristics of standing waves allows to find the result for the speed of the wave is:
The speed wave is: v = 10 m / sThe wave is a way of transmitting energy without mass displacement, , in the attachment we can see a diagram of the standing wave.
Each cycle corresponds to half a wavelength, they indicate that the frequency is 2.50 Hz and there are three cycles, so the wavelength is:
L = [tex]n \frac{\lambda}{2}[/tex]
λ = 2L/n
λ = 2 6 /3
λ = 4 m
Wave speed is related to wavelength and frequency
v = λ f
v = 4 2.5
v = 10 m / s
In conclusion, using the characteristics of standing waves we can find the result for the speed of the wave is:
The wave speed is: v = 10 m / sLearn more here: brainly.com/question/12536719
Choose the items that are examples of unalienable rights.
A) criticizing the government
B) to live wherever you want to
C) the government requiring safety standards in cars
D) preventing unpopular religions from holding services
E) not having the government listen to your phone calls
I NEED HELP ASAP
Answer:
the answer is D
Explanation:
bc the goverment cannot stop any religion from its service
The examples of unalienable rights include:
To live wherever you want to.The government requiring safety standards in cars.Not having the government listen to your phone calls.In the declaration of Independence, the unalienable rights include life, liberty, and the pursuit of happiness.
It should be noted that one can live wherever one wants to. Also, one has the right to religion and should not be disturbed from practicing their religion. The government doesn't have the right to listen to one's phone calls too.
In conclusion, the correct options are A, C, and E.
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What is defined by force per unit area?
1: gravity
2: force
3: temperature
4: pressure
Answer:
4. pressure is defined as force per unit area
Pressure is defined by force per unit area.
WHAT IS PRESSURE:Pressure refers to the force applied to a substance per unit area. Force is measured in Newtons (N) while area is measured in m², hence, the unit of pressure is N/m² also called pascal.Therefore, according to this question, it can be said that pressure is defined by force per unit area
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Bob is riding in a roller coaster, and is at the top of a vertical loop (shown below). The radius of the loop is 18 meters. If his apparent weight is just 28% of his actual weight, what is the speed of the roller coaster? Show all your steps.
In a game of tug of war, team one pulls to the right with a force of 500 newtons and team two pulls to the left with a force of 600 newtons. What is the net force?
Answer:
Explanation:
There is no set way to do this. All you have to do is define left and right. Left will be minus and right will be the opposite --- plus.
That is completely arbitrary. It could be the other way around. It does not matter.
Left is minus so: - 600 N is the force going left.
Right plus so: + 500 N
Now just add.
Net Force = +500 - 600
Net Force = - 100 N
So the Net Force is - 100 N going to the left.
HELP PLEASE
What is the correct definition of amplitude?
A. the height of a wave
B. the distance between two crests or troughs
C. the number of complete waves that pass a point in a second
D. the time it takes for one complete wave to pass a given point
Answer:
correct answer is A) the height of a wave
Explanation:
i just did the test:)
The amplitude is used represent the height of the wave.
What is wave?A wave is a disturbance in a medium that carries energy without a net movement of particles. In general, waves are classified into two types as Longitudinal and Transverse
Given is the amplitude of a wave.
Amplitude of a wave is equal to measure of the length of crest or trough. Crest and trough are the points that represents the maximum and minimum displacement of the wave with respect to the reference axis. The crest and the trough points are both at a equal straight line distance from the reference axis. This distance is also called height of the wave. The amplitude is the distance between the centerline and the Crest or trough. The general equation representing the amplitude of wave is x = A sin (ωt + ϕ) or x = A cos (ωt + ϕ) is the formula.
Therefore, the amplitude represents the height of the wave.
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A baseball is hit straight up in the air with an initial velocity of 38 m/s
How long does it stay in the air?
How high does it go?
The time of motion or time spent in air by the baseball is 7.76 seconds.
The maximum height attained by the baseball is 73.67 m.
The given parameters;
initial velocity of the baseball, u = 38 m/sThe time of motion of the baseball is calculated using the first kinematic equation as follows;
v = u - gt
where;
t is the time to reach maximum heightv is the final velocity of the ball at the maximum height = 00 = u -gt
gt = u
[tex]t = \frac{u}{g} \\\\\t = \frac{38}{9.8} \\\\t = 3.88 \ s[/tex]
The time spent in the air = time of entire motion = 2(3.88 s) = 7.76 seconds
The maximum height attained by the ball is calculated using the second kinematic equation as shown below;
[tex]h = ut -\frac{1}{2} gt^2\\\\h = (38\times 3.88)\ - \ (0.5 \times 9.8 \times 3.88^2)\\\\h = 73.67 \ m[/tex]
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A car accelerates at 4 m/s/s from rest. What is the car's velocity after it travels 20 m?
A uniform string of length 0.50 m is fixed at both ends. Find the
wavelength of the fundamental mode of vibration. If the wave
speed is 300 mis, find the frequency of the fundamental and next
possible modes.
Answer:
configuration of string:
Node - Antinode - Node or N-A-N
This is 1/2 wavelength since a full wavelength is N-A-N-A-N
f (fundamental) = V / wavelength
F0 = 300 m/s / 1 m = 100 / sec
F1 = 300 m/s / .5 m = 600 / sec
Each increase is a multiple of the fundamental since the wavelength
increases by 1/2 wavelength to keep nodes at both ends of the string
Câu 20: Chọn câu sai:
A. Công là đại lượng vô hướng B. Công không có tính tương đối
C. Công phụ thuộc vào đường đi D. Công có giá trị đại số
Answer:
fr
Explanation:
identify impacts of air pollution
Answer:
Explanation:
High levels of air pollution can cause an increased risk of heart attack, wheezing, coughing, and breathing problems, and irritation of the eyes, nose, and throat. Air pollution can also cause worsening of existing heart problems, asthma, and other lung complications.
Ambient air pollution accounts for an estimated 4.2 million deaths per year due to stroke, heart disease, lung cancer and chronic respiratory diseases. Around 91% of the world's population lives in places where air quality levels exceed WHO limits.
Serious Effects of Pollution on Our Humans and Environment
Environment Degradation. The environment is the first casualty for the increase in pollution weather in air or water. ...
Human Health. ...
Global Warming. ...
Ozone Layer Depletion. ...
Infertile Land.
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Thank you,
Miss Hawaii
Jasmine pushing her little brother on the swing the swing passes back-and-forth 14 times in 40 seconds what is the frequency of the motion and what is superior to the swing
Answer:
Explanation:
frequency f = 14 cycles/40 s
f = 0.35 cycles/s or
f = 0.35 Hz.
I suspect you are more concerned with the PERIOD of the swing rather than what is superior to it. (How would one even compare?)
T = 1/f = 1/0.35
T = 2.85714285...
T = 2.86 s
Which requires more work, lifting a 20 kg box vertically 2 meters OR lifting a 10 kg box 4 meters? Explain.
Answer:
I'm not sure in which direction 10kg is lifted but assuming 10kg is lifted (or dragged) horizontally then
the 20kg vertically requires more work because gravity pushing down on it will require a somewhat large output of Energy.
But if they are both lifted vertically (or horizontally)then they are equal in work.
Hope this helps
How are acceleration and velocity related
A: An object with constant velocity also has constant acceleration
B: Acceleration and velocity are not related. C:Acceleration describes how fast the velocity of an object is changing,
D: Acceleration only occurs when the speed of an object changes, but velocity can change if speed or direction changes
Answer:
answer is C
Explanation:
acceleration is rate of changing velocity in a time
Mr. Jones's prescription calls for 1.04 tablets per day. Based on this information, how many tablets should Mr. Jones take per day? a) 1.25 O b) 1.5 c) 1 O d) 2
Due to the fact that no one can consume .04 of a tablet, we can round down this answer to 1. This means that Mr. Jones should take C- 1 tablet per day.
I hope I've helped! :)
Mr. Jones's prescription calls for 1.04 tablets per day. Based on this information, he should take 1 tablet per day. The correct option is C.
What is prescription?The doctor suggests the medicine to be taken by the patient for the treatment of any disease or symptom is called as prescription.
Mr. Jones's prescription calls for 1.04 tablets per day. Based on this information, Mr. Jones must take 1 tablet per day.
No one can consume .04 of a tablet, we can round off 1.04 to 1. This means that Mr. Jones should take 1 tablet per day.
Thus, the correct option is C.
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A double concave lens is a ________ lens, and a double convex lens is a ______ lens.
a.
converging, diverging
c.
converging, converging
b.
diverging, converging
d.
diverging, diverging
Answer:
b. diverging, converging
Answer:diverging, converging
Explanation: