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Arlecino [84]
3 years ago
10

. Calculate the efficiency of a bicycle if the input work to turn the pedal is 45J and the output work is 20J. * 1 point 2.25 2.

25% 44 44.4%
Physics
1 answer:
cestrela7 [59]3 years ago
8 0

20/45=0.4*100= 44.4 so the answer is..................................................

Answer: 44.4%

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An airplane flying at a speed of 130 mi/h (58.1 m/s) and at an altitude of 4.9 km drops a food package. Without a parachute, at
telo118 [61]

The food package will strike the ground at 11 degrees below the horizontal.

<h3>Time for the food package to hit the ground</h3>

The time for the food package to hit the ground is calculated as follows;

h = vt + ¹/₂gt²

<em>let the initial velocity be horizontal</em>

4900 = 0(t) + (0.5 x 9.8)t²

4900 = 4.9t²

t² = 4900/4.9

t² = 1,000

t = √1,000

t = 31.62 s

<h3> Final speed of the food package when it hits ground</h3>

vf(y) = vo + gt

vf(y) = 0 + (31.62 x 9.8)

vf(y) = 309.88 m/s

<h3>Angle of projection</h3>

The horizontal component of the speed will be constant, while vertical component will change

tan(\theta ) = \frac{V_y}{V_x} \\\\\theta = tan^{-1} (\frac{V_y}{V_x})\\\\\theta = tan^{-1} (\frac{309.88}{58.1} )\\\\\theta = 79^0

Angle below the horizontal = 90 - 79 = 11⁰

Thus, the food package will strike the ground at 11 degrees below the horizontal.

Learn more about angle of projection here: brainly.com/question/10671136

4 0
2 years ago
A ring with an 18mm diameter falls off a scientist's finger into the solenoid in the lab. The solenoid is 25 cm long, 5.0 cm in
Troyanec [42]

Answer:

The value is  \epsilon =  3.84 *10^{-5} \  V

Explanation:

From the question we are told that

  The diameter of the ring is  d =  18 \ mm  =  0.018 \  m

   The length of the solenoid is l = 25 \ cm  =  0.25 \ m

   The diameter of the solenoid is  D = 5.0 \ cm  = 0.05 \ m

    The number of turns is  N = 1500

   The change in  current in the solenoid is   \Delta  I   = 20 \ A

   The time taken is  \Delta  t  = 1 \ s

Generally the radius of the ring is  

     r = \frac{d}{2}

=>  r = \frac{0.018 }{2}

=>  r = 0.009 \ m

Generally the area of the ring is mathematically represented as  

      A = \pi r^2

=>   A = 3.142 *  0.009^2    

=>   A = 2.545 *10^{-4}\ m^2

Generally the induced emf is mathematically represented as

       \epsilon  =  A * \frac{dB}{dt}

Here    

         \frac{dB }{dt} =  \mu_o * \frac{N}{l} *\frac{ \Delta I }{\Delta t}

Here  \mu_o is the permeability of free space with value  

         \mu_o =  4\pi *10^{-7} \ N/A^2

So  

     \frac{dB }{dt} =   4\pi * 10^{-7} * \frac{1500}{0.25} *\frac{20 }{1}

=>  \frac{dB }{dt} =   0.150816\  T/s

So

     \epsilon =   0.150816 *  2.545 *10^{-4}

=>   \epsilon =  3.84 *10^{-5} \  V

3 0
3 years ago
If al snow and glaiers melted, would the sea level rise or fall
Kobotan [32]
The sea level would rise because the snow and glaciers are water 

4 0
3 years ago
Energy from the Sun arrives at the top of the Earth’s atmosphere with an intensity of 1.30kW/m21.30⁢kW/m2. How long does it take
vivado [14]

Answer:

T=1.384×10⁶seconds

Explanation:

Given data

p (Intensity)=1.30 kw/m²

E (Energy)=1.8×10⁹ J

A (Area)=1.00 m²

T (Time required)=?

Solution

E=PT   ................eq(i)

where E is energy

P is radiation power

T is time

Radiating Power is given as

P=pA

Where p is intensity

A is Area

Put P=pA in eq(i) we get

E=pAT

T=E/pA

T=\frac{(1.8*10^{9}}{(1.30*10^{3} )*(1.00)}  )\\T=1.38*10^{6} seconds

3 0
3 years ago
All fires require oxygen () There is no oxygen in that room (T) .
Marina CMI [18]

The sentences are invalid and unsound.

<h3><u>Explanation</u>:</h3>

The fire is defined as the vigorous oxidation of a substance. Now oxidation can occur in presence of any oxidising agent. Like magnesium in presence of nitrogen in high temperature with a dazzling brownish flame to produce magnesium nitride. So fire can be produced in absence of oxygen.

Oxygen is present everywhere in world. So production of a whole room without oxygen is very tough to produce and costly process. So its very unsound.

4 0
3 years ago
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