A 20- kg and a 50-kg ball rest at the top of a ramp. Which statement best describes the potential energy of the balls?

Answer:

10s

Explanation:

Horizontal velocity is the velocity of an object in an horizontal direction

The ball's horizontal velocity is approximately 33.078 ft./s

Reason:

The known parameter are;

The horizontal distance the footballer kicks the ball, d = 43 yards

The time after which the ball lands, Δt = 3.9 seconds

Required:

To find the velocity of the ball

Solution:

[tex]Velocity = \dfrac{Distance}{Time} = \dfrac{d}{\Delta t}[/tex]

Therefore;

[tex]Horizontal \ velocity \ of \ the \ ball, \ v_x= \dfrac{43 \ yard}{3.9 \ seconds} \approx 11.026 \ yd/s[/tex]

The ball's horizontal velocity, vₓ ≈ 11.026 yd/s

1 yard = 3 feet

[tex]11.026 \ yard = 11.026 \ yard \times \dfrac{3 \ feet}{yard} = 22.078 \ feet[/tex]

The ball's horizontal velocity, vₓ ≈ 33.078 ft./s

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Answer:

P = 360 Watts

Explanation:

Given that,

The weight of a student, [tex]F=5.4\times 10^2\ N[/tex]

It takes 15 seconds to run up a hill.

The top of the hill is 10 meters vertically above her starting point.

We need to find the power develop during her run. We know that te power developed is given by :

[tex]P=\dfrac{W}{t}\\\\P=\dfrac{mgh}{t}\\\\P=\dfrac{5.4\times 10^2\times 10}{15}\\\\P=360\ W[/tex]

So, the power develop during her run is 360 W.

Answer:

T = 1.41 seconds

Explanation:

Given that,

The mass placed in the pendulum, m = 10 kg

The length of the pendulum, l = 0.5 m

We need to find the period of the pendulum. The relation for the period of the pendulum is given by :

[tex]T=2\pi \sqrt{\dfrac{l}{g}} \\\\T=2\pi \sqrt{\dfrac{0.5}{9.8}} \\\\T=1.41\ s[/tex]

So, the time period of the pendulum is 1.41 seconds.

For anyone that needs the correct answer without POS trolls:

The answer is 1.4 s

Thank me later :)

Answer:

The Force that resists the motion of one object moving relative to another is Friction. Kinetic Friction Resists the motion of Moving objects, while Static friction keeps the objects from moving.

Answer:

Acceleration = 0.5m/s²

Explanation:

Given the following data;

Final velocity = 5m/s

Time = 10 seconds

Since the spider started from rest, its initial velocity is equal to 0m/s

To find the acceleration;

In physics, acceleration can be defined as the rate of change of the velocity of an object with respect to time.

This simply means that, acceleration is given by the subtraction of initial velocity from the final velocity all over time.

Mathematically, acceleration is given by the equation;

[tex]Acceleration (a) = \frac{final \; velocity - initial \; velocity}{time}[/tex]

[tex]a = \frac{v - u}{t}[/tex]

Where,

a is acceleration measured in [tex]ms^{-2}[/tex]

v and u is final and initial velocity respectively, measured in [tex]ms^{-1}[/tex]

t is time measured in seconds.

Substituting into the equation, we have;

[tex]a = \frac{5 - 0}{10}[/tex]

[tex]a = \frac{5}{10}[/tex]

Acceleration = 0.5m/s²

Answer:

 t ’= [tex]\frac{1450}{0.6499 + 2 v_r}[/tex],  v_r = 1 m/s       t ’= 547.19 s

Explanation:

This is a relative velocity exercise in a dimesion, since the river and the boat are going in the same direction.

By the time the boat goes up the river

        v_b - v_r = d / t

By the time the boat goes down the river

        v_b + v_r = d '/ t'

let's subtract the equations

       2 v_r = d ’/ t’ - d / t

       d ’/ t’ = 2v_r + d / t

       [tex]t' = \frac{d'}{ \frac{d}{t}+ 2 v_r }[/tex]

In the exercise they tell us

         d = 1.22 +1.45 = 2.67 km= 2.67 10³ m

         d ’= 1.45 km= 1.45 1.³ m

at time t = 69.1 min (60 s / 1min) = 4146 s

the speed of river is v_r

      t ’= [tex]\frac{1.45 \ 10^3}{ \frac{ 2670}{4146} \ + 2 \ v_r}[/tex]

      t ’= [tex]\frac{1450}{0.6499 + 2 v_r}[/tex]

In order to complete the calculation, we must assume a river speed

          v_r = 1 m / s

let's calculate

      t ’= [tex]\frac{ 1450}{ 0.6499 + 2 \ 1}[/tex]

      t ’= 547.19 s

Answer:

a) time taken to catch up with speeding car is 12.25 secs

b) the police car will travel 273.8 m to catch up with the speeding car

Explanation:

Given that;

speed of car [tex]V_{c}[/tex] = 50 mi/hr = 22.352 m/s

acceleration of police car = 10 mi/hr = 4.47 m/s²

[tex]V_{f}[/tex]  = 70 mi/hr = 31.29 m/s

Now time taken to reach maximum speed is t₁

so

[tex]V_{f}[/tex] =  [tex]V_{i}[/tex] + at₁

we substitute

31.29 = 0 + 4.47t₁

t₁ = 31.29 / 4.47

t₁  = 7 sec

now

d₁ = 0 + 1/2 × at₁²

d₁ = 0 + 1/2 × 0 + 4.47×(7)²

d₁ = 109.5 m

so distance travelled by the speeding car in time t₁  will be

[tex]d_{c}[/tex] = [tex]V_{c}[/tex] × t₁

we substitute

[tex]d_{c}[/tex] = 22.352 × 7

[tex]d_{c}[/tex]  = 156.46 m

now distance between polive car and speeding car

Δd =  [tex]d_{c}[/tex] - d₁

Δd = 156.46 - 109.5

Δd = 46.96 m

time taken to cover Δd will be

t₂ = Δd / ( [tex]V_{f}[/tex] - [tex]V_{c}[/tex] )

t₂ = 46.96 / ( 31.29 - 22.352 )

t₂ = 46.96 / 8.938

t₂ = 5.25 sec

distance travelled by the police in time t₂ will be

d₂ = [tex]V_{f}[/tex] × t₂

d₂ = 31.29 × 5.25

d₂ = 164.3 m

a) How long will it take before the officer catches up to the speeding car;

time taken to catch up with speeding car;

t = t₁ + t₂

t = 7 + 5.25

t = 12.25 secs

Therefore, time taken to catch up with speeding car is 12.25 secs

b)  how far will it have travelled in order to do so;

distance = d₁ + d₂

distance = 109.5 + 164.3

distance = 273.8 m

Therefore, the police car will travel 273.8 m to catch up with the speeding car

A star produces energy by creating helium from hydrogen in its core (option D).

A star is a luminous celestial body, made up of plasma (particularly hydrogen and helium) and having a spherical shape.

Nuclear fusion is the energy-producing process in stars. The "proton-proton chain," a series of events that turns four hydrogen atoms into one helium atom, dominates this process for the majority of stars.

Nuclear fusion is the combining of the nuclei of small atoms to form the nuclei of larger ones, with a resulting release of large quantities of energy.

Hydrogen atoms fuse in the core of the star to form a helium atom, which generates the energy for the star.

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Answer:

Explanation:

Considering non - relativistic approach : ----

Speed of electron = 1 % of speed of light

= .01 x 3 x 10⁸ m /s

= 3 x 10⁶ m /s

Kinetic energy of electron = 1/2 m v²

= .5 x 9.1 x 10⁻³¹ x ( 3 x 10⁶ )²

= 40.95 x 10⁻¹⁹ J

Kinetic energy in electron comes from lose of electrical energy equal to

Ve where V is potential difference under which electron is accelerated and e is electronic charge .

V x e = kinetic energy of electron

V x 1.6 x 10⁻¹⁹ = 40.95 x 10⁻¹⁹

V = 25.6 Volt .

Answer:

a) The final pressure is 1.68 atm.

b) The work done by the gas is 305.3 J.

Explanation:

a) The final pressure of an isothermal expansion is given by:

[tex] T = \frac{PV}{nR} [/tex]

[tex] T_{i} = T_{f} [/tex]

[tex] \frac{P_{i}V_{i}}{nR} = \frac{P_{f}V_{f}}{nR} [/tex]

Where:

[tex]P_{i}[/tex]: is the initial pressure = 5.79 atm

[tex]P_{f}[/tex]: is the final pressure =?

[tex]V_{i}[/tex]: is the initial volume = 420 cm³

[tex]V_{f}[/tex]: is the final volume = 1450 cm³

n: is the number of moles of the gas

R: is the gas constant

[tex] P_{f} = \frac{P_{i}V_{i}}{V_{f}} = \frac{5.79 atm*420 cm^{3}}{1450 cm^{3}} = 1.68 atm [/tex]

Hence, the final pressure is 1.68 atm.

b) The work done by the isothermal expansion is:

[tex] W = P_{i}V_{i}ln(\frac{V_{f}}{V_{i}}) = 5.79 atm*\frac{101325 Pa}{1 atm}*420 cm^{3}*\frac{1 m^{3}}{(100 cm)^{3}}ln(\frac{1450 cm^{3}}{420 cm^{3}}) = 305.3 J [/tex]

Therefore, the work done by the gas is 305.3 J.

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The velocity of the freely falling object reached after 4.0 s is equal to 39.2 m/s.

A relation can be established between the velocity of the body and acceleration of the body when the body is moving along a straight line with uniform acceleration. The distance traveled by the body in a specific time has expressed a set of equations called equations of motion.

The first equation of motion can be expressed as follows:

v = u + at

Where u is the initial velocity, v is the final velocity and a is the acceleration and t is the time of the object.

Given, the acceleration of the falling object, g = 9.8 m/s²

The initial velocity of the object, u = 0, and the time = 4 sec

The velocity of the object after time, t = 4 sec.

v = (0) + (9.80)× (4)

v = 39.2 m/s

Therefore, the velocity of the falling object will be 39.2 m/s after 4 seconds.

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Answer:

Ultraviolet rays from sun are very harmful from skin and can cause sunburn and skin diseases especially ultraviolet B rays. A sunscreen  lotion act as a protection barrier on the skin that restrict the direct contact of UV rays with skin and filter the harmful rays to enter the skin.

Radiotherapy is a medical therapy use to treat cancer. Radiotherapy commonly uses x-rays and gamma rays because they are high-energy particles or waves that kills or destroys the cancer cells.

Sunscreen lotion is able to filter this damaging ultraviolet radiation and prevent it from damaging the skin.

The sun reaches us from outer space brings ultraviolet rays to us. Ultraviolet rays are known to have some damaging effects on the skin. One way to protect our skin from this damaging ultraviolet rays is to use sunscreen lotion which is able to filter this damaging ultraviolet radiation and prevent it from damaging the skin.

X-rays and gamma rays are used in radiotherapy because they are light energy rays which are able to penetrate and destroy malignant cells in the body.

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Answer:

an action-reaction pair is because one of the objects is often much more massive and appears to remain motionless when a force acts on it. It has so much inertia, or tendency to remain at rest, that it hardly

Answer:

Explanation:

a ) from San Antonio to Houston let distance be d km .

Average speed = total distance / total time

time = distance / speed

Total time = (d / 2 x 75 ) +( d / 2 x 106 )

= .0067 d + .0047 d

= .0114 d

Average speed  = d / .0114 d = 87.72 km /h

b ) from Houston back to San Antonio

Total time = (d / 2 x 106 ) +( d / 2 x 75 )

= .0047 d + .0067 d

= .0114 d

Average speed  = d / .0114 d = 87.72 km /h

c )

For entire trip :

total distance = 2d

total time = 2 x .0114 d

Average speed  = 2 d / 2 x .0114 d

= 87.72 km /h .

Answer:

Honestly, I don't know ¯\_(ツ)_/¯

Explanation:

Answer:

suppose buying pizza for a work party leads to positive morale and to the work being done in half the time. Pizza is the independent variable, Work speed is the dependent variable, The mediator, the middle man without which there would be no connection, is positive morale. Denaturation, in biology, the process of modifying the molecular structure of a protein. Denaturation involves the breaking of many of the weak linkages, or bonds (e.g., hydrogen bonds), within a protein molecule that is responsible for the highly ordered structure of the protein in its natural (native) state.

Explanation:

hope this helps have a good rest of your day :) ❤

Explanation:

HW1. For example, suppose buying pizza for a work party leads to positive morale and to the work being done in half the time. Pizza is the independent variable, Work speed is the dependent variable, The mediator, the middle man without which there would be no connection, is positive morale.

HW2. The word denature means to render food unpleasant or dangerous to consume, it is denatured by adding a substance known as a denaturant. Aversive agents—primarily bitterants and pungent agents—are used to produce an unpleasant flavor.

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Please Mark As Brainl

Answer:

Please see below as the answer is self-explanatory.

Explanation:

Answer:

12N

Explanation:

given- mass, acelation

Fnet=ma= .16kg*75m/s2

Fnet=12 N only force no friction given.

Answer:

you would be better off if the car bounced backwards

Explanation:

because if the hood was dismembered than you have a high chance of very bad injury but if it is just bounced back you would have less chance of getting hurt if properly sitting and seat belted.

Answer:

Explanation:

Maximum height reached = 90.6 m . Range = 48.5 m

. Let u be the initial velocity at angle α .

Horizontal range is covered by horizontal component of u .

Vertical height is achieved by vertical component

v² = u² sin² α - 2gh , t is time taken to attain maximum height .

0 = u² sin² α - 2 x 90.6 x 9.8  

u² sin² α = 2 x 887.88  -------( 1 )

Range R = u² sin2α / g

48.5 = 2 u² sinα . cos α / 9.8

u² sinα . cos α = 237.65 -----------------------------  ( 2 )

( 1 ) / ( 2 )

Tan α = 2 x 887.88 / 237.65 = 7.47

α = 82⁰

u² sin² α = 2 x 887.88

u² sin² 82 = 2 x 887.88

u² = 1812

u = 42.56  m /s

Answer:

4=Conduction by convection by radiation.

Explanation:

Hope it will help you! It may be short but I don't know how to write it in blank aafai milayera lekha Hai blanks ma

Answer:

Force = 607.95 Newton

Explanation:

Given the following data;

Area = 0.00600 m^2

Pressure = 1 atm to Pascal = 101325 Pa

To find the force;

Pressure = Force/area

Force = pressure * area

Substituting into the equation, we have;

Force = 101325 * 0.00600

Force = 607.95 Newton.

Therefore, the amount of force exerted by the air on the stamp is 607.95 Newton.

Answer:

B. Light energy can exist independently of matter.

Explanation:

In science, matter can be defined as anything that has mass and occupies space. Any physical object that is found on earth is typically composed of matter. Matter are known to be made up of atoms and as a result has the property of existing in states.

Generally, matter exists in three (3) distinct or classical phases and these are;

I. Solid.

II. Liquid.

III. Gas.

Light energy is different from both sound and heat energy because light energy can exist independently of matter.

Generally, we know that light energy is a type of electromagnetic waves and as such do not require a medium of propagation for it to travel through a vacuum of space where no particles exist. For example, light energy from distant galaxy of stars and the sun.

However, both sound and heat energy are mechanical waves which are highly dependent on matter for their propagation and transmission.

Answer:

KE = ½mv²

KE = ½5kg×(20m/s)²

KE = ½5kg×400m²/s²

KE =5kg×200m²/s²

KE = 1000joules

Answer:

Option 10. 169.118 J/KgºC

Explanation:

From the question given above, the following data were obtained:

Change in temperature (ΔT) = 20 °C

Heat (Q) absorbed = 1.61 KJ

Mass of metal bar = 476 g

Specific heat capacity (C) of metal bar =?

Next, we shall convert 1.61 KJ to joule (J). This can be obtained as follow:

1 kJ = 1000 J

Therefore,

1.61 KJ = 1.61 KJ × 1000 J / 1 kJ

1.61 KJ = 1610 J

Next, we shall convert 476 g to Kg. This can be obtained as follow:

1000 g = 1 Kg

Therefore,

476 g = 476 g × 1 Kg / 1000 g

476 g = 0.476 Kg

Finally, we shall determine the specific heat capacity of the metal bar. This can be obtained as follow:

Change in temperature (ΔT) = 20 °C

Heat (Q) absorbed = 1610 J

Mass of metal bar = 0.476 Kg

Specific heat capacity (C) of metal bar =?

Q = MCΔT

1610 = 0.476 × C × 20

1610 = 9.52 × C

Divide both side by 9.52

C = 1610 / 9.52

C = 169.118 J/KgºC

Thus, the specific heat capacity of the metal bar is 169.118 J/KgºC

Answer:

1.a) 3.93 m/s

 b) 0.80 s

2. a) 8.49 m

   b) 0.39 s

Explanation:

1. a) The speed at which the fox leaves the snow can be found as follows:

[tex] v_{f}^{2} = v_{0}^{2} - 2gH [/tex]

Where:

g: is the gravity = 9.80 m/s²

[tex]v_{f}[/tex]: is the final speed = 0 (at the maximum height)

[tex]v_{0}[/tex]: is the initial speed =?

H: is the maximum height = 79 cm = 0.79 m

[tex] v_{0} = \sqrt{2gH} = \sqrt{2*9.80 m/s^{2}*0.79 m} = 3.93 m/s [/tex]

Hence, the speed at which the fox leaves the snow is 3.93 m/s.

b) The time at which the fox reaches the maximum height is given by:

[tex]v_{f} = v_{0} - gt[/tex]

[tex]t = \frac{v_{0} - v_{f}}{g} = \frac{3.93 m/s}{9.80 m/s^{2}} = 0.40 s[/tex]

Now, the time of flight is:  

[tex] t_{v} = 2t = 2*0.40 s = 0.80 s [/tex]

2. a) The maximum height the ball reaches is:

[tex] H = \frac{v_{0}^{2} - v_{f}^{2}}{2g} = \frac{(12.9 m/s)^{2}}{2*9.80 m/s^{2}} = 8.49 m [/tex]

Then, the maximum height is 8.49 m.

b) The time at which the ball passes through half the maximum height is:

[tex]y_{f} = y_{0} + v_{0}t - \frac{1}{2}gt^{2}[/tex]

Taking y₀ = 0 and [tex]y_{f}[/tex] = 8.49/2 = 4.245 m we have:

[tex] 4.245 m -12.9m/s*t + \frac{1}{2}*9.80m/s^{2}*t^{2} = 0 [/tex]  

By solving the above quadratic equation we have:

t = 0.39 s

Therefore, the time at which the ball passes through half the maximum height when the ball is going up is 0.39 s.

I hope it helps you!