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Sati [7]
3 years ago
11

A boy sledding down a hill accelerates at 1.40 m/s². If

Physics
1 answer:
mrs_skeptik [129]3 years ago
5 0

Answer: He would reach 7m/s at the distance of 17,5m.

Explanation: In order for us to know how long it takes for the speed to be reached, we use the equation V= Vo + at, with V=7m/s, Vo= 0m/s since you start from rest and a=1.4m/s². T is the time in seconds that we want to find out.

7 = 0 + 1.4t

7 = 1.4t

t= 5s

Now, we want to know the distance this boy reaches in 5 seconds, in a 7m/s speed and accelarating in 1.4m/s². For finding this out, we use another equation, S = So + Vot + (at²)/2, S being the final distance, So = 0m because he started from rest, and the other variables used before.

S = 0 + 0*5 + [1.4*(5²)]/2

S = 0 + 0 + (1.4*25)/2

S = 35/2

S = 17,5m

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Two pipes move the same amount of ideal fluid in the same amount of time. One pipe has a 2 in. diameter; the other has a 3 in. d
xxTIMURxx [149]
By Bernoulli Theorem, We know, that for any two points in the pipe, total energy would be same. 

Pressure Energy + K.E. of 1st pipe = Pressure Energy + K.E. of 2nd pipe
[ No need to consider Potential energy as height isn't mentioned] 
P₁ + mv₁²/2 = P₂ + mv₂²/2

So, we know, P + mv²/2 = constant

As value of kinetic energy is larger in larger in 2 in. pipe [ 'cause area is indirectly proportional to velocity ], Value of pressure energy would be smaller in it. So, pressure energy will be higher in the pipe of 3 in.

In short, option A would be your correct answer.

Hope this helps!



6 0
3 years ago
The jogger ran 3km east.
erma4kov [3.2K]

Answer: d

Explanation:

7 0
4 years ago
How does a generator use the effect you noticed in the pickup coil to generate electrical energy? What energy transformations ar
Oksana_A [137]

Answer:

Movement of Electrons in opposite direction of the rotation of the pickup coil leads to the direction of Electrical energy ( Alternating current ).

Explanation:

For a Generator to generate electricity, Electrons that is found in the rotating coil of the Generator will experience some sort of force that makes them to start moving in a direction that is perpendicular to the direction of the rotating/pickup coil found in the Generator.

The conversion of mechanical energy (Rotation of the pickup coil ) to electrical energy takes place in the Generator

The generator makes an alternating current because electrons move in opposite direction of the rotating coil

In other to generate a Direct current using a generator we have to replace the slip rings with commutator.

6 0
3 years ago
Which of the following statements best describes the second law of
Serga [27]

Answer:

B

Explanation:

Heat flows from hot to cold to lower the temperature of hot areas and increase temperature of cold areas. The end result is that the 2 areas have the same temperature, thus increasing entropy.

7 0
4 years ago
A 0.44-kg cord is stretched between two supports, 8.1 m apart. When one support is struck by a hammer, a transverse wave travels
padilas [110]

Answer: 9.8N

Explanation: The velocity of a sound wave (v), tension on the string (T) and mass per unit length (u) are all related by the formulae below

T = v² * u

Where T is tension in Newton (N), v is velocity of sound waves in meter per seconds (m/s) and u is mass per unit length in kilogram per meter (kg/m)

u = mass of chord / length of chord

u = 0.44/ 8.1

u = 0.1 kg/m

Velocity of sound waves (v) =length of chord / time taken for wave to travel

v = 8.1 / 0.82 = 9.9m/s

Tension is calculated below using the formula

T = v² * u

T = (9.9)² x 0.1

T= 9.8N

7 0
3 years ago
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