Emmy kicks a soccer ball up at an angle of 45° over a level field. She watches the ball's trajectory and notices that it lands, two seconds after being kicked, about 20 m away to the north. Assume that air resistance is negligible, and plot the horizontal and vertical components of the ball's velocity as a function of time. Consider only the time that the ball is in the air, after being kicked but before landing. Take "north" and "up" as the positive x ‑ and y ‑directions, respectively, and use g≈10 m/s2 for the downward acceleration due to gravity.

If we assume the collision to be elastic the final velocity of the ball will be  -8.65 m/s, therefore the correct option is D.

It is a type of Collison for which the momentum, as well as the kinetic energy after and before the collision, is constant. there is no loss of energy in a perfectly elastic collision.

By using the law of conservation of momentum

momentum before collision = momentum after the collision

the initial momentum of rocket +initial momentum, of ball = final momentum of rocket + final momentum of the ball

By substituting the respective values

-1.75 + 0.00684 = -1.25 + m*v

-1.75 + 0.00684 = -1.25 + 0.057*v

v = -8.65 m/s

Thus, the final velocity of the ball is -8.65 m/s

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Complete Question

A 940-g rock is whirled in a horizontal circle at the end of a 1.30-m-long string,  If the breaking strength of the string is 120 N, what's the minimum angle the string can make with the horizontal?

Answer:

The value is [tex]\theta = 4.41^o[/tex]      

Explanation:

From the question we are told that

  The mass of the rock is  [tex]m_r = 940 \ g = 0.94 \ kg[/tex]

   The length of the string is [tex]l = 1.30 \ m[/tex]

    The breaking strength(i.e the maximum tension) on the string is [tex]T = 120 \ N[/tex]

Gnerally the vertical component of the tension experienced by the string is mathematically represented as

     [tex]T_v = T sin(\theta)[/tex]

Generally this vertical component  of tension is equivalent to the weight of the rock

So

     [tex]Tsin (\theta) = mg[/tex]

=>  [tex]\theta = sin^{-1} [\frac{mg}{ T} ][/tex]

=>    [tex]\theta = sin^{-1} [\frac{0.940 *9.8 }{ 120} ][/tex]

=>    [tex]\theta = 4.41^o[/tex]      

Answer:

Explanation:

The acceleration of an object given it's mass and the force acting on it can be found by using the formula

[tex]a = \frac{f}{m} \\ [/tex]

where

m is the mass

f is the force

We have

[tex]a = \frac{275}{18} \\ = 15.277777...[/tex]

We have the final answer as

Hope this helps you

Answer:

1- bounce rule

2- left

3-11,2

4-true

5- whiffle ball

6- kitchen

7-false

8- ping pong

9- true

10- true

Explanation:

I'm pre5sure they are all right. brainliest please

Answer: I had the same quiz too I’m only doing so the other guy can get brainliest

Explanation:Kfkfkfjgjggj

Answer:

it will take half of the initial time to reach double the velocity

Explanation:

Given that a car accelerates from rest to a certain velocity in a certain time.

Since the car accelerate from rest, the initial velocity U = 0

Using the first equation of motion,

V = U + at

V = at

Assume that there is no friction, and that the engine power is constant. Consider the following scenarios independently. How long would it take to reach double the velocity (also from rest)

That is V = 2V

Using the same formula ,

2( at ) = at

2T = t

T = t/2

Therefore, it will take half of the initial time to reach double the velocity

Answer:

22.3 kg•m/s

Explanation:

Apex;)

Answer:

a) 1.4 m/s2

b) 63N

c) 6.66kg

Answer:

We are given:

m = 1500 kg

initial velocity (u) = 35 m/s

final velocity (v) = 0 m/s

time (t) = 5 seconds

acceleration = a m/s/s

Force (f) = F  newtons

Solving for acceleration:

Using the first equation of motion:

v = u + at

replacing the variables

0 = 35 + a(5)

a = -35/5

a = -7 m/s/s

Force applied by the brakes:

From newton's second law of motion:

F = ma

replacing the variables

F = (1500)(-7)

F = -10500 N

Therefore, the force applied by the brakes is -10500 N, we have a negative sign since the force is being applied opposite to the direction of motion

Answer:

-) It is less than 8 [N]

See the explanation below.

Explanation:

To solve this problem we must analyze each of the answers, and in this way, we will come to the right solution. The most important thing is to keep in mind that the body is moving to the left.

-) It is equal to 8 [N]

This answer is not possible, since if the Force F was equal to 8 [N] the body would be in equilibrium and the body would not move.

-)  It is equal to 10 [N]

This answer is not possible, since if Force F is greater than 8 [N] the body would move to the right.

-)  It is greater than 10 [N]

This answer is not possible, since if Force F is greater than 8 [N] the body would move to the right.

-) It is less than 8 [N]

This is the correct option, as the force of 8 [N] will move the body to the left.

Answer:

Approximately 17.21 seconds

Explanation:

With subtraction, we have the gazelle 18.3 km/h slower than the cheetah, which is about 5.08333 m/s. As the gazelle is 87.5 meters ahead of the cheetah, 87.5 divided by 5.083333333 is about 17.21 seconds.

Which object? More information is needed to answer this question

Answer:

The new freezing point of water is -0.476°C.

Explanation:

Given that,

Mass of water = 4.62 kg

Mass of CaBr₂ = 236.5 g

We need to calculate the molality of solution

Using formula of molality

[tex]m=\dfrac{mass\ of\ CaBr_{2}}{molar\ mass\ of\ CaBr_{2}\times mass\ of\ water}[/tex]

Put the value into the formula

[tex]m=\dfrac{236.5}{200\times4.62}[/tex]

[tex]m=0.256\ mol/kg[/tex]

[tex]m=0.256\ m[/tex]

We need to calculate the depression in freezing point of water

Using formula of freezing point

[tex]\Delta T=m\times k[/tex]

Where, k = depression constant

m = molality of solution

Put the value into the formula

[tex]\Delta T=0.256\times1.86[/tex]

[tex]\Delta T=0.476^{\circ}C[/tex]

We know that,

The standard freezing point of water is 0°C

We need to find the new freezing point of water

Using formula for freezing point of water

Freezing point of 4.62 kg of water = freezing point of water-depression in freezing point of water

[tex]\Delta T'=0-\Delta T[/tex]

Put the value into the formula

[tex]\Delta T'=0-0.476[/tex]

Hence, The new freezing point of water is -0.476°C.

Answer:

an electro magnet is technology contain at least one permanent magnet

Answer:

The second choice

Explanation:

I think the answer is the second choice because if the surface is smooth, there is less friction. With a boat, it is easier to pull it on water than on the sand, because water has less friction, and thus, the answer is the second choice because rough surfaces have more friction.

Hopefully the explanation and answer helps!

Answer:

20.83rad/s

Explanation:

Using the law of conservation of momentum

m1u1+m2u2 = (m1+m2)v

m1 and m2 are the mass of the disc and Brick respectively

u1 and u2 are the linear velocities respectively

v is their final velocity of the block-disc system

Given

m1 = 100kg

m2 = 20kg

u1 = wr =25×1.6

u1 = 40m/s

u2 = 0m/s (brick is stationary)

Substitute and the final linear velocity v

100(40)+20(0) = (100+20)v

4000 = 120v

v = 4000/120

v = 33.3m/s

From the formula;

v = wr

w = v/r

w= 33.3/1.6

w = 20.83rad/s.

Hence the final angular speed of the disc-brick system is 20.83rad/s

Answer:

Atoms in a solid are close and tightly packed.They vibrate about fixed positions .They are arranged in a regular LATTICE.They cannot be compressed nor can they change shape.They have strong forces of attraction between them so they cannot move in order to move they have to gain ENERGY. Whereas the atoms in a liquid are not that close compared to the ones in solid.They take the shape of the container but their volume remains fixed.They have weak forces of attraction between atoms and have more energy which enables them to move.

Explanation:

Answer:

Induced emf = 0

Explanation:

An emf can be induced due to the change in magnetic field. It can be given by :

[tex]\epsilon=\dfrac{d\phi}{dt}\\\\\because \phi=BA\cos\theta\\\\\epsilon=\dfrac{d(BA\cos\theta)}{dt}\\\\\epsilon=A\cos\theta\dfrac{dB}{dt}[/tex]

As the loop is placed perpendicular to a uniform magnetic field of 1 Tesla. It means that [tex]\theta=90^{\circ}[/tex] and cos(90) = 0. Hence, the induced emf is equal to 0.

Answer:

the set of all real numbers

Explanation:

Given the cost of the magazine expressed as:

c=45+3.75m where:

c describes the cost of the yearly subscription.

m is the amount of order.

You must understand that domain are the values of the input variable m that will make the function exist.

The value of m that will produce a positive output since we can only have a positive value of the cost. According to the option, we can say that the domain is on the set of all real numbers (some are negative but all positive real numbers)

Answer:

Mass was added to the water particles, resulting in deposition.

Explanation:

Answer:  The energy was removed from the water particles resulting in condensation

Explanation Think about when you leave a cup of ice of and after a while you see water droplets thats what happened to the grass in the morning and thats called condensation.

Answer:

19.3 m/s

Explanation:

Take down to be positive.  Given:

Δy = 19 m

v₀ = 0 m/s

a = 9.8 m/s²

Find: v

v² = v₀² + 2aΔy

v² = (0 m/s)² + 2 (9.8 m/s²) (19 m)

v = 19.3 m/s

Answer:

The maximum energy that can be transferred to an electron in a single collision of alpha particle is 1.63 keV

Explanation:

let mass of electron, Me = 1

let mass of proton, Mp = 1836Me = 1836

let mass of alpha particle, Ma = 4Mp = 7344

The maximum energy that can be transferred to an electron in a single collision is given by;

[tex]Q_{max} = \frac{4mME}{(M+m)^2}\\\\Q_\alpha_{max} = \frac{4(1)(7344)(3\ MeV)}{(1+7344)^2} = 0.00163 \ MeV = 1.63 \ KeV[/tex]

Therefore, the maximum energy that can be transferred to an electron in a single collision of alpha particle is 1.63 keV

Answer:

[tex]h_p = 30.46\ m[/tex]

Explanation:

Free Fall Motion

A free-falling object refers to an object that is falling under the sole influence of gravity. If the object is dropped from a certain height h, it moves downwards until it reaches ground level.

The speed vf of the object when a time t has passed is given by:

[tex]v_f=g\cdot t[/tex]

Where [tex]g = 9.8 m/s^2[/tex]

Similarly, the distance y the object has traveled is calculated as follows:

[tex]\displaystyle y=\frac{g\cdot t^2}{2}[/tex]

If we know the height h from which the object was dropped, we can solve the above equation for t:

[tex]\displaystyle t=\sqrt{\frac{2\cdot y}{g}}[/tex]

The stadium is h=32 m high. A pair of glasses is dropped from the top and reaches the ground at a time:

[tex]\displaystyle t_1=\sqrt{\frac{2\cdot 32}{9.8}}=2.56\ sec[/tex]

The pen is dropped 2 seconds after the glasses. When the glasses hit the ground, the pen has been falling for:

[tex]t_2=2.56 - 2 = 0.56\ sec[/tex]

Therefore, it has traveled down a distance:

[tex]\displaystyle y=\frac{9.8\cdot 0.56^2}{2} = 1.54\ m[/tex]

Thus, the height of the pen is:

[tex]h_p = 32 - 1.54\Rightarrow h_p=30.46\ m[/tex]

The pen is 30.52 m above the ground.

Given that the height of the stadium is h = 32m

The initial velocity of the glasses will be 0.

[tex]h=\frac{1}{2}gt^{2} \\t=\sqrt{\frac{2h}{g} } \\t=\sqrt{\frac{2*32}{9.8} }\\t=2.55s[/tex]is the time taken for the glasses to hit the ground.

Now the pen is released 2 seconds later. So by the time the glasses hit the ground the pen has spent:

[tex]t^{'}=2.55-2\\t^{'}=0.55s[/tex]in the air

distance traveled by the pen:

[tex]d=\frac{1}{2}gt^{2}\\\\d=\frac{1}{2}*9.8*0.55*0.55\\\\d=1.48m[/tex]

So the pen is  [tex]h-d=32-1.48=30.52m[/tex]  above the ground.

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Answer:

answer: 105 sin 30 = 52.5

Answer:

The size of the magnetic force on the wire due to the Earth's magnetic field is 4.62 × 10⁻⁶ N.

Explanation:

To determine the size of the magnetic force on the wire due to the Earth's magnetic field,

The magnetic force is given by the formula

F = ILB sinθ

Where F is the magnetic force on the wire

I is the electric current in Amperes (A)

L is is the length of wire in meters (m)

B is the magnetic field in Tesla (T)

and θ is the angle between current and magnetic field

From the question,

L = 0.30 m

I = 0.50 A

B = 0.50 gauss = 0.5 × 10⁻⁴ T (NOTE: 1 Gauss = 10⁻⁴ Tesla)

θ = 38°

Now, putting the values into the equation

F = ILB sinθ

F = 0.50 × 0.30 × 0.5 × 10⁻⁴ sin38°

F = 7.5 × 10⁻⁶ (0.61566)

F = 4.62 × 10⁻⁶ N

Hence, the size of the magnetic force on the wire due to the Earth's magnetic field is 4.62 × 10⁻⁶ N.

Answer:

Yes, the number of electrons determines the chemical properties of the atom.

Explanation:

Answer:

The table is 2.08 m high

Explanation:

Horizontal Motion

When an object is thrown horizontally with a speed vo from a height h, 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]

If we know the range d = 0.15 m and the speed v = 0.23 m/s, we can solve the above equation for h:

[tex]\displaystyle h=\frac{d^2\cdot g}{2v^2}[/tex]

[tex]\displaystyle h=\frac{0.15^2\cdot 9.8}{2\cdot 0.23^2}[/tex]

[tex]\boxed{h=2.08\ m}[/tex]

The table is 2.08 m high

Answer:

when your heart rate is not high than normal or lower than normally

Explanation:

Recovery heart rate is when your heart recovers from a certain heart rate eg high heart rate or even low heart rate this means you heart is now functioning normally .

Answer:

Number of beats per minute the heart drops after exercise.

Answer: The motion of a ball falling down through the atmosphere, or a model rocket being launched up into the atmosphere are both examples of Newton's first law. The motion of a kite when the wind changes can also be described by the first law.

Explanation: