An example of Repression would be?

A student with a mass of 65.5 kg runs up a flight of 18 stairs. Each of the steps has a height of 16.5 cm. The student was able

Helga [31]

The power developed by the student is 756.9 J/s and remains the same if the student takes the same time to climb the stairs when climbing it in two's and three's.

<h3>What is power?</h3>

Power is the rate at work is done.

Power = work done/time
work done = mass × acceleration due to gravity × height

Work done = 65.5 × 10 × (18 × 0.165) = 1945.35 J

Power = 1945.35/2.57 = 756.9 J/s

If the student climbed the steps in two or three at a time, the power does not change if the time remains the same.

Time required = Energy/ power

The time required to convert the Big Mac meal from McDonalds = 4 853 440/756.9

Time required = 6412.26 seconds

Therefore, from the power developed by the student, it will take him 6412.26 seconds to convert all the energy in a Big Mac meal.

Learn more about power at: brainly.com/question/1634438

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5 0

2 years ago

Two conductors are made of the same material and have the same length. Conductor A is a solid wire of diameter 1.0 mm.

pantera1 [17]

Answer:

R_a/R_b=3

Explanation:

The resistance in terms of the area and the length of the wire is given by:

R=pL/A

if we have two wires, the first one is a solid wire with a diameter of d_A = 1 x 10^-3 m, and the second one is a hollow wire with inner diameter of d_B,i = 1 x 10^-3 m and outer diameter of d_B,σ= 2 x 10^-3 m, so the cross sectional area of the first wire is:

A_a=πr^2_a

A_a=πd^2_A/4

hence the resistance is:

R_a=(4*p*L_a)/π*d^2_A (1)

the area of the second wire is:

A_b=π*r^2_B,σ-π*r^2_B,i

A_b=π/4(d^2_B,σ-d^2_B,i)

hence the resistance is:

R_b=(4*p*L_b)/π(d^2_B,σ-d^2_B,i) (2)

To find the ratio between the resistances R_a/R_b, we divide (1) over (2) to get:

R_a/R_b=(d^2_B,σ-d^2_B,i)*L_a/(d^2_a*L_b)

but the wires have the same length, therefore:

R_a/R_b=(d^2_B,σ-d^2_B,i)/(d^2_a)

substitute with the given values to get:

R_a/R_b=3

6 0

3 years ago

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A hot-air balloon is rising straight up with a speed of 4.6 m/s. a ballast bag is released from rest relative to the balloon at

kherson [118]

The time taken by the ballast bag to reach the ground is 2.18 s

The ballast bag at rest with respect to the balloon has the upward velocity (u) of 4.6 m/s , which is the velocity of the balloon. When it is dropped from the balloon, its motion is similar to an object thrown upwards with an initial velocity <em>u </em>and it falls under the acceleration due to gravity<em> g.</em>

Taking the upward direction as positive and the downward direction as negative, the following equation of motion may be used.

$s=ut+\frac{1}{2}at^2$

The bag makes a net displacement <em>s</em> of 13.4 m downwards, hence

$s=-13.4 m$

Its initial velocity is

$u=+4.6 m/s$

The acceleration due to gravity acts downwards and hence it is negative.

$g=-9.8 m/s^2$

Use the values in the equation of motion and write an equation for t.

$s=ut+\frac{1}{2} at^2 \\ -13.4=4.6t-\frac{1}{2}(9.8)t^2\\ 4.9t^2-4.6t-13.4=0$

Solving the equation for t and taking only the positive value for t,

t=2.18 s

4 0

3 years ago

An engineer is designing a spring to be placed at the bottom of an elevator shaft. If the elevator cable should happen to break

mamaluj [8]

Answer:

Value that the spring constant k = 12Mg / h

Explanation:

According to 2nd law of Newton:

upward force of the spring= F

The weight of the elevator W = mg

F = Mg = M(5g)

==> F =6Mg.

As the spring is compressed to its maximum distance ie s,the maximum upward acceleration comes just , Hence

F =ks = 6Mg

==> s = 6Mg/k

We have gravitational potential energy turning into elastic potential of the spring as the elevator starts at the top some distance h from the spring, and undergoes a total change in height equal to h + s, so:

Mg(h+s) = 1/2ks2

And plugging in our expression for s:

Mg(h+6Mg/k)= 1/2k(6Mg / k)2

gh + 6M2g2/k = 1/2k(36M2g2 /k2)

Mgh +6M2g2/k = 1/2k(36M2g2 /k2)

gh + 6Mg2/k = 18Mg2 / k

gh = 12Mg2 / k

h = 12Mg / k

k = 12Mg / h

7 0

4 years ago

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What is the most commonly used method of food preservation today? refrigeration drying foods smoking raw meats salt curing

dmitriy555 [2]

Refrigerator was what is commonly used today. We do dry foods and salt cure but that is not done on a daily basis

6 0

4 years ago

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