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Helga [31]
2 years ago
12

A sled having a certain initial speed on a horizontal surface comes to rest after traveling 10 m. If the coefficient of kinetic

friction between the object and the surface is 0.20, what was the initial speed of the object
Physics
1 answer:
sergiy2304 [10]2 years ago
5 0

Answer:

the initial speed of the object is 6.26 m/s

Explanation:

given information:

distance, s = 10 m

the coefficient of kinetic friction, μ = 0.2

we use the equation where the kinetic energy is equal to the friction force.

kinetic energy, KE = \frac{1}{2} mv^{2}

friction work,  W = F(friction) s

KE = W

\frac{1}{2} mv^{2} = F(friction) s

where, F(friction) = μ N, N is normal force (N = m g)

                            = μ m g

so,

\frac{1}{2} mv^{2} = μ m g s

\frac{1}{2} v^{2} = μ g s

v^{2} = 2 μ g s

  = 2 (0.2) (9.8) (10)

  = 39.2

hence,

v = \sqrt{3.92}

  = 6.26 m/s

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An object is projected with initial speed v0 from the edge of the roof of a building that has height H. The initial velocity of
Vsevolod [243]

Answer:

Explanation:

Initial velocity u = V₀ in upward direction so it will be negative

u = - V₀

Displacement s = H . It is downwards so it will be positive

Acceleration = g ( positive as it is also downwards )

Using the formula

v² = u² + 2 g s

v² = (- V₀ )² + 2 g H

= V₀² + 2 g H .

v = √ ( V₀² + 2 g H )

6 0
2 years ago
A bag of potato chips contains 2.00 L of air when it is sealed at sea level at a pressure of 1.00 atm and a temperature of 20.0°
Genrish500 [490]

Answer:

The volume at mountains is 2.766 L.

Explanation:

Given that,

Volume V_{1} = 2.00\ L

Pressure P_{1}= 1.00\ atm

Pressure P_{2}= 70.0\ kPa

Temperature T_{1}= 20.0°C = 293\ K

Temperature T_{2}= 7.00°C = 280\ K

We need to calculate the volume at mountains

Using  gas law

\dfrac{PV}{T}=\ Constant

For both temperature,

\dfrac{P_{1}V_{1}}{T_{1}}=\dfrac{P_{2}V_{2}}{T_{2}}

Put the value into the formula

\dfrac{101.325\times2}{293}=\dfrac{70\times V_{2}}{280}

V_{2}=\dfrac{101.325\times2\times280}{293\times70}

V_{2}=2.766\ litre

Hence, The volume at mountains is 2.766 L.

5 0
2 years ago
You are piloting a small airplane in which you want to reach a destination that is 750 km due north of your starting location. O
alexira [117]

Answer:

v_wind = 101.46 km / h   ,  θ = 61.8

Explanation:

This is a velocity composition exercise.

Let's do the problem in parts. Let's start by knowing the speed of the plane without air.

           v = d / t

           v = 750 / 3.14

           v = 238.85 km / h

This is the speed of the plane relative to the Earth and it does not change.

In the second part, when there is wind, the travel time is greater than when there is no wind, therefore the wind delays the plane. To be more general, suppose that the wind has two components vₓ and v_{y}

Let's use trigonometry to find the components of the plane's speed

          cos θ = v_N / v

          sin θ  = v_W / v

          v_N = v cos θ

          v_W = v sin θ

           

let's calculate

          V _N = 238.85 cos 22 = 221.46 km / h

           v_W = -238.85 sin 22 = -89.47

the negative sign is because the plane is going west and the positive sign is the east direction.

As it indicates that the destination of the avine is towards the north, the x component of the wind must be

              vₓ - v_W = 0

              vₓ = v-w

              vₓ = 89.47 km / h

in the direction to the East.

Now let's analyze the component of the wind in the Nort-South direction,

Indicate the travel time, let's calculate the speed that the component must have the speed of the plane

             v_total = d / t

             v_total = 750 / 4.32

             v_total = 173.61 km / h

This is the final speed of the plane, which can be written

              v_total = v_n - vy

               vy = v_n - v_total

               vy = 221.46 - 173.61

               vy = 47.85 km

this component is directed towards the south

Let's use the Pythagorean Theorem, to find the magnitude

             v_wind² = vₓ² + vy²

             v_wind = √ (89.47² + 47.85²)

             v_wind = 101.46 km / h

the address will then be found using trigonometry

             θ = Vy / vx

             θ = tan⁻¹ (vy / vx)

             θ = tan⁻¹1 (47.85 / 89.47)

             θ = 28.14

Therefore, the magnitude of the wind speed is 101.5 km / h and its direction is 28º south of the East, to give this value

                  90- θtea = 90- 28.2

                  θ = 61.8

East of South

5 0
1 year ago
A mass of 0.4 kg hangs motionless from a vertical spring whose length is 0.76 m and whose unstretched length is 0.41 m. Next the
Blizzard [7]
<h3><u>Answer;</u></h3>

= 1.256 m

<h3><u>Explanation;</u></h3>

We can start by finding the spring constant  

F = k*y  

Therefore;  k = F/y = m*g/y

                               = 0.40kg*9.8m/s^2/(0.76 - 0.41)

                               = 11.2 N/m  

Energy is conserved  

Let A be the maximum displacement  

Therefore;  1/2*k*A^2 = 1/2*k*(1.20 - 0.41)^2 + 1/2*m*v^2  

Thus;  A = sqrt((1.20 - 0.55)^2 + m/k*v^2)

               = sqrt((1.20 -0.55)^2 + 0.40/9.8*1.6^2)

                = 0.846 m  

Thus; the length will be 0.41 + 0.846  = 1.256 m

6 0
2 years ago
The resistivity of a semiconductor can be modified by adding different amounts of impurities. A rod of semiconducting material o
zavuch27 [327]

Answer:

pp

Explanation:

7 0
2 years ago
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