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Natali [406]
3 years ago
14

Why do helium balloons float? Talk about density of atoms and compare to elements in the air.

Physics
1 answer:
xxMikexx [17]3 years ago
7 0
The helium balloon displaces an amount of air. As long as the weight of the helium balloon fabric is lighter than the air it displaces, the balloon will float in the air. It turns out helium is a lot lighter than air.
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During a testing process, a worker in a factory mounts a bicycle wheel on a stationary stand and applies a tangential resistive
olganol [36]

Answer:

The force is     F_c  =  789.03 \  N    

Explanation:

From the question we are told that

   The tangential  resistive force is F_t  =   115 \ N

   The mass of the wheel is  m  = 1.80 kg

  The diameter of the wheel is  d =  50.0 cm  = 0.5 \ m

   The diameter of the sprocket is  d_c  =  8.50 \ cm =0.085 \ m

  The angular acceleration considered is  \alpha  =  4.30\ rad/s^2

Generally the radius of the wheel is

       r = \frac{d}{2}

=>     r = \frac{0.5}{2}

=>     r = 0.25 \ m

Generally the radius of the sprocket is

       r_c = \frac{d_c}{2}

=>     r_c = \frac{0.085}{2}

=>     r_c = 0.0425 \ m

Generally the moment of inertia of the wheel is mathematically represented as

      I  =  m  *  r^2

=>    I  =  1.80  *  0.25^2

=>    I  = 1.1125 \ kg \cdot m^2

Generally the torque experienced by the wheel due to the forces acting on it  is mathematically represented as

      \tau =  F_c *  r_c  -  F_t  * r

Here  F_c is the force acting on the sprocket

So  

      \tau =  F_c *  0.0425 - 115  * 0.25

       \tau = 0.0425F_c  -  28.75

Generally the torques that will cause the wheel to move with \alpha  =  4.30\ rad/s^2 is mathematically represented as

       \tau  =  I  * \alpha

So

        0.0425F_c  -  28.75  =   I  * \alpha

        0.0425F_c  -  28.75  =   1.1125  *4.30    

       0.0425F_c  -  28.75  =   1.1125  *4.30    

        F_c  =  789.03 \  N    

5 0
3 years ago
PLEASE HELP ILL MARK BRAINLIEST!!! A ball is initially thrown downwards with an initial speed of 20 m/s from the top of a 300 m
Sholpan [36]

Using the 3rd equation of motion:

= v² - u² = 2gs ------ [g = Acceleration due to gravity]

= v² - 20² = 2 × 10 × 300

= v² - 400 = 6000

= v² = 6000 - 400

= v = √5600

= v = 74.83 m/s

And yeah it's done :)

8 0
3 years ago
Terry can ride 30 miles in 2 hours. If his riding speed is
Anni [7]

Answer:  20.4 miles

Explanation:

Here we need to use the equation:

Velocity = Distance/Time.

Initially we have that he can travel 30 miles in 2 hours, so the velocity is:

V = 30mi/2h = 15mph

Now, we reduce the velocity by 3 mph, so the new velocity is 15mph - 3 mph = 12mph.

Now we want to know the distance traveled in 1.7 hours with this velocity, this is.

Velocity*Time = Distance

12mi/h*1.7h = 20.4 miles

7 0
3 years ago
A ‘thermal tap’ used in a certain apparatus consists of a silica rod which
abruzzese [7]

Correct question is;

A thermal tap used in a certain apparatus consists of a silica rod which fits tightly inside an aluminium tube whose internal diameter is 8mm at 0°C.When the temperature is raised ,the fits is no longer exact. Calculate what change in temperature is necessary to produce a channel whose cross-sectional is equal to that of the tube of 1mm. (linear expansivity of silica = 8 × 10^(-6) /K and linear expansivity of aluminium = 26 × 10^(-6) /K).

Answer:

ΔT = 268.67K

Explanation:

We are given;

d1 = 8mm

d2 = 1mm

At standard temperature and pressure conditions, the temperature is 273K.

Thus; Initial temperature; T1 = 273K,

Using the combined gas law, we have;

P1×V1/T1 = P2×V2/T2

The pressure is constant and so P1 = P2. They will cancel out in the combined gas law to give:

V1/T1 = V2/T2

Now, volume of the tube is given by the formula;V = Area × height = Ah

Thus;

V1 = (πd1²/4)h

V2 = (π(d2)²/4)h

Thus;

(πd1²/4)h/T1 = (π(d2)²/4)h/T2

π, h and 4 will cancel out to give;

d1²/T1 = (d2)²/T2

T2 = ((d2)² × T1)/d1²

T2 = (1² × T1)/8²

T2 = 273/64

T2 = 4.23K

Therefore, Change in temperature is; ΔT = T2 - T1

ΔT = 273 - 4.23

ΔT = 268.67K

Thus, the temperature decreased to 268.67K

6 0
3 years ago
What force would be required to accelerate a 1,100kg car to 0.5 m/s2
OlgaM077 [116]

Answer:

the force required to accelerate a 1,100kg car is 550N

5 0
3 years ago
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