1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
OLga [1]
3 years ago
10

A player kicks a football (from the ground) at an initial angle of 30°. The football is in the air for 2.4 s before it hits an o

pposing player. The opposing player was a horizontal distance x = 50 m away from where the football was kicked. What was the initial horizontal velocity component of the football?

Physics
1 answer:
wolverine [178]3 years ago
8 0

Answer:

The initial horizontal velocity was 21 m/s

Explanation:

Please, see the figure for a better understanding of the problem.

The equation for the position of an object moving in a parabolic trajectory is as follows:

r = (x0 + v0 · t · cos α, y0 + v0 · t · sin α + 1/2 · g ·t²)

Where:

r = vector position at time t

x0 = initial horizontal position

v0 = initial velocity

t = time

α = launching angle

y0 = initial vertical position

g = acceleration due to gravity

Notice that at time t = 2.4 s the vector "r" is the one in the figure. We know that the x-component of that vector is 50 m. Then using the equation for the x-component of the vector "r", we can calculate the initial velocity:

x = x0 + v0 · t · cos α

Let´s place the center of the frame of reference at the point of the kick so that x0 = 0.

x =  v0 · t · cos α

x/t = v0 · cos α

Notice in the figure that v0 · cos 30° = v0x which is the initial horizontal velocity. Remember trigonometry of right triangles:

cos α = adjacent / hypotenuse = v0x / v0

Then:

50 m/ 2.4 s = v0 · cos 30° = v0x

v0x = 21 m/s

You might be interested in
Will mark as brainliest if correct!!!!!!!!!!!
Aneli [31]

Answer:

The answer is A.

Explanation:

The diagram shows the light ray bending away from the normal. Light rays bend away from the normal when their speed increases. This means that in the diagram, the light ray moves from a medium in which light has a lower speed to a medium in light has a higher speed. The only choice where the speed of light increases from A to B is answer A. So that has to be the answer.

7 0
3 years ago
Is N2 a triple bond
krek1111 [17]
Yes, N2 is a triple bond.
Hope it helps!
5 0
3 years ago
A succession of single tones or pitches perceived as a unit is called:
jeka57 [31]
A succession of single tones or pitches perceived as a unit is called a melody. It is a linear succesion of tones in music that is seen as one single entity. It is a combination of rhythm, pitch and tonal color. Melodies usually has one ormore motifs or phrases that are being repeated all throughout a composition. Melodies are characterized by the melodic motion it posses , the pitch, intervals between the pitches, continuity and pitch range. Due to the a wide range of melodies that can be made from tones, differet genres of music arise. Examples are Jazz, Rock music, Classical, pop, R&B and the like. 
5 0
3 years ago
An AA battery is connected to a parallel-plate capacitor having 3.9cm×3.9cm plates spaced 1.5 mm apart. How much charge does the
djyliett [7]

Answer:

Q = 1.35*10⁻¹¹ C.

Explanation:

By definition, the capacitance of a capacitor, is the charge on one of the plates, divided by the potential difference between them, as follows:

C= \frac{Q}{V}

At the same time, we can show (applying Gauss' Law to the surface of one of the plates), that the capacitance of a parallel-plate capacitor (with a dielectric of air), can be written as follows:

C = ε₀*A / d

Replacing by the values of A, and d, and taking into account that

ε₀ = 8.85*10⁻¹² F/m,

we get the value of the capacitance as follows:

C = 8.97*10⁻¹² F

As the voltage of an AA battery is 1.5 V, and is all applied to the capacitor, we can conclude that the charge on one of the plates is as follows:

Q = C* V = 8.97*10⁻¹² F* 1.5 V = 1.35*10⁻¹¹ C

5 0
3 years ago
Read 2 more answers
Can someone help me with this physics question? I don't know which answer is correct.
san4es73 [151]

3. Distance is a quantity that is always a vector.

B.

5 0
2 years ago
Other questions:
  • Operators must slow to no wake speed when within what distance of a u.s. naval vessel?
    11·2 answers
  • A satellite orbits the earth a distance of 2.50 × 10^7 m above the planet’s surface and takes 6.43 hours for each revolution abo
    8·1 answer
  • In the formula vy = ayt, what is the value of ay for an object in projectile motion?
    10·2 answers
  • What is the marble's range if it is fired horizontally from 1.6 m above the ground?
    9·1 answer
  • Sully uses a battery and a coil of wire to create an electromagnet. Using the same materials, if he wants to increase the streng
    9·2 answers
  • Sometimes, when the wind blows across a long wire, a low-frequency "moaning" sound is produced. The sound arises because a stand
    15·1 answer
  • As an object moves along the x axis, many measurements are made of its position, enough to generate a smooth, accurate graph of
    12·2 answers
  • Choose the correct statement concerning units of power or energy. a. A kilojoule (kJ) is a unit of power. b. A gigawatt (GW) is
    7·1 answer
  • A grandfather clock has a pendulum that consists of a thin brass disk of radius r = 13.62 cm and mass 1.199 kg that is attached
    8·1 answer
  • A projectile is fired horizontally from a height of 78.4 m at a speed of 300 m/sec. How far did it travel horizontally before hi
    11·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!