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Lena [83]
3 years ago
13

help me.. a car moves for half of its time at 80km/h nd for rest of time at 40km/h.total distance coverd is 60km..wat is averge

speed of car?
Physics
1 answer:
nalin [4]3 years ago
5 0
Let's use ' t ' to represent half of the time, in hours.

The distance traveled in the first half of the time is  (80 t) km.

The distance traveled in the last half of the time is  (40 t) km.

The total distance covered is    (80t + 40t) = (120t)  km.

You said that the total distance covered was  60 km,
so ...
                             120 t  =  60 km

Divide each side by  120 :      t (half of the time) = 0.5 hour

Average speed = (total distance covered) / (time to cover the distance)

                           =      (60 km)  /  (1 hour)

                           =            60 km/hr .
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a cone is constructed by cutting a sector from a circular sheet of metal with radius . the cut sheet is then folded up and welde
Svet_ta [14]

The expression for the radius and height of the cone can be obtained from

the property of a function at the maximum point.

  • The \ radius, \ of \ the \ base \ of \ the \ cone \ is \ \sqrt{ \dfrac{3}{4}} \times radius \ of \ circular \ sheet \ metal
  • The height of the cone is half the length of the radius of the circular sheet metal.

Reasons:

The part used to form the cone = A sector of a circle

The length of the arc of the sector = The perimeter of the circle formed by the base of the cone.

Volume \ of \ a \ cone = \dfrac{1}{3} \cdot  \pi \cdot r^3 \cdot h

  • Volume \ of \ a \ cone, \, V = \dfrac{1}{3} \cdot  \pi \cdot r^3 \cdot \sqrt{(s^2- r^2)}

θ/360·2·π·s = 2·π·r

Where;

s = The radius of he circular sheet metal

h = s² - r²

  • \dfrac{dV}{dr} = \dfrac{d}{dr}  \left(\dfrac{1}{3} \cdot  \pi \cdot r^3 \cdot \sqrt{(s^2- r^2)}\right) = \dfrac{\pi \cdot (3 \cdot r^2 \cdot  s^2 - 4 \cdot r^4)}{\sqrt{(s^2- r^2)}} = 0

3·r²·s² - 4·r⁴ = 0

3·r²·s² = 4·r⁴

3·s² = 4·r²

\underline{\left  \right. The \ radius, \, r =\sqrt{ \dfrac{3}{4}} \cdot s}

\underline{The \ height, \, h =\sqrt{s^2 - \dfrac{3}{4}\cdot s^2} = \dfrac{s}{2}}}

Learn more here:

brainly.com/question/14466080

3 0
2 years ago
What's the frequency of a wave with a wavelength of 10 and velocity of 200m/s?
uranmaximum [27]

Answer:

\boxed {\boxed {\sf 20 \ Hz}}

Explanation:

The frequency of a wave can be found using the following formula.

f=\frac{v}{\lambda}

where <em>f</em> is the frequency, <em>v</em> is the velocity/wave speed, and λ is the wavelength.

The wavelength is 10 meters and the velocity is 200 meters per second.

  • 1 m/s can also be written as 1 m*s^-1

Therefore:

v= 200 \ m*s^{-1} \\\lambda = 10 \ m

Substitute the values into the formula.

f=\frac{200 \ m*s^{-1}}{10 \ m}

Divide and note that the meters (m) will cancel each other out.

f=\frac{200 \ s^{-1}}{10 \ }

f=20 \ s^{-1}

  • 1 s^-1 is equal to Hertz
  • Therefore, our answer of 20 s^-1 is equal to 20 Hz

f= 20 \ Hz

The frequency of the wave is <u>20 Hertz</u>

7 0
2 years ago
The flow control circuit design that can best control an overrunning load is the ____ circuit.
lara31 [8.8K]

The meter out circuit is the flow control circuit design that can most effectively control an overrunning load.

The meter-out circuit can be very accurate, but are not efficient. The meter-out circuit can control overrunning as well as opposing loads while the other one method must be used with opposing loads only. The choice of flown control valve method and the location of the flow control in the circuit are dependent on the type of application being controlled.

<h3>What is a Circuit ?</h3>

In electronics, a circuit is a complete circular conduit through which electricity flows. A simple circuit consists of conductors, a load, and a current source. The term "circuit" broadly refers to any continuous path via which electricity, data, or a signal might flow.

  • The directional valve shifts, causing the actuator to move faster than pump flow can fill it due to an overrunning load. Oil is leaking from one side, whereas there is none on the other.

Hence, flow control circuit design that can best control an overrunning load is the opposing circuit

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#SPJ4

3 0
2 years ago
9. A Veggie meatball with v = 5.0 m/s rolls off a 1.0 m high table. How long does it take to hit the floor if no one sneezes? Wh
Paha777 [63]

By Considering the vertical distance and both vertical and horizontal final velocity, the time t = 0.45 s and Velocity V = 6.7 m/s

Given that a Veggie meatball with v = 5.0 m/s rolls off a 1.0 m high table.

Height h = 1.0 m

As the ball rolls off the table, it will be fallen under gravity. Where

g = 9.8 m/s^{2}

Initial vertical velocity u_{y} = 0

Initial horizontal velocity u_{x} = 5 m/s

Considering the vertical distance, the formula to use to calculate the time will be;

h = ut + 1/2gt^{2}

1 = 0 + 1/2 x 9.8t^{2}

1 = 4.9t^{2}

t^{2} = 1/4.9

t = \sqrt{0.204}

t = 0.45 seconds

It takes 0.45 seconds to hit the floor if no one sneezes.

To calculate its velocity when it hits the floor, we will need to calculate for both vertical and horizontal final velocity and find the resultant velocity of the two.

Vertical component

V_{y} = U_{y} + gt

V_{y} = 0 + 9.8(0.45)

V_{y} = 4.41 m/s

Horizontal component

V_{x} = u_{x} + at

but a = 0

V_{x} = 5 m/s

Final velocity V = \sqrt{5^{2} + 4.41^{2}  }

V = 6.67 m/s

Therefore, it will hit the floor at a velocity of 6.7 m/s

Learn more here: brainly.com/question/5063616

8 0
2 years ago
An object of unknown mass is initially at rest and dropped from a height h. It reaches the ground with a velocity v1 . The same
Hatshy [7]

Answer:

v_2=\sqrt{2}v_1

Explanation:

The velocity v₁ can be calculated with the kinematic formula:

v_1^{2} =v_0^{2} +2gh

Since the object is initially at rest, v₁ becomes:

v_1=\sqrt{2gh}

Where g is the acceleration due to gravity. Now, the velocity v₂ can be calculated with the same formula, but now the initial velocity is v₁:

v_2^{2}=v_1^{2} +2gh

Substituting v₁ in this expression and solving for v₂, we get:

v_2^{2}=(\sqrt{2gh} )^{2} +2gh=4gh\\\\\implies v_2=\sqrt{4gh}=2\sqrt{gh}

Now, dividing v₂ over v₁, we get the expression:

\frac{v_2}{v_1}=\frac{2\sqrt{gh} }{\sqrt{2gh}}=\sqrt{2}\\   \\\implies v_2=\sqrt{2}v_1

It means that v₂ is √2 times v₁.

4 0
3 years ago
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