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vitfil [10]
3 years ago
10

An athlete is working out in the weight room. He steadily holds 50 kilograms above his head for 10 seconds. Which statement is t

rue about this situation?
A.
The athlete isn’t doing any work because he doesn’t move the weight.
B.
The athlete isn’t doing any work because he doesn’t hold the weight long enough.
C.
The athlete is doing work because he prevents the weight from falling downward.
D.
The athlete is doing work because 50 kilograms is a significant load to lift.
Physics
1 answer:
postnew [5]3 years ago
3 0

Answer:

A. The athlete isn’t doing any work because he doesn’t move the weight.

Explanation:

We must remember the definition of work, which says that work is equal to the product of mass by the distance displaced. In this case, the athlete only does work when he lifts the weight from the ground to the point where he holds the weight suspended.

So when he's holding the weight, he doesn't do any work.

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A wire loop of radius 0.37 m lies so that an external magnetic field of magnitude 0.35 T is perpendicular to the loop. The field
Galina-37 [17]

Answer:

168.57 mV

Explanation:

Initial magnetic flux = BA , B magnetic field and A is area of loop

= .35 x 3.14 x .37²

= .15 Weber

Final magnetic flux

= - .2 x 3.14 x .37²

= -  .086 Weber

change in flux

.15 +  .086

= .236 Weber

rate of change of flux

= .236 / 1.4

= .16857 V

= 168.57 mV

5 0
3 years ago
A 6 kg bowling ball is accelerated at a rate of 2.3 m/s² down the lane. How much force was necessary to produce this acceleratio
Maurinko [17]
The answer is D hoped this helped
4 0
3 years ago
A house has well-insulated walls. It contains a volume of 105 m3 of air at 305 K.
REY [17]

Answer: 85.46\ kJ

Explanation:

Given

Volume of air V=105\ m^3

Temperature of air T=305\ K

Increase in temperature \Delta T=0.7^{\circ}C

Specific heat for diatomic gas is C_p=\dfrac{7R}{2}

Energy required to increase the temperature is

\Rightarrow Q=nC_pdT\\\\\Rightarrow Q=n\times \dfrac{7R}{2}\times \Delta T\\\\\Rightarrow Q=\dfrac{7}{2}nR\Delta T\\\\\Rightarrow Q=\dfrac{7}{2}\times \dfrac{PV}{T}\times \Delta T\quad [\text{using PV=nRT}]

Insert the values

\Rightarrow Q=\dfrac{7}{2}\times \dfrac{1.01325\times 10^5\times 105}{305}\times 0.7\\ \text{Assuming air pressure to be atmospheric P=}1.01325\times 10^5\ N/m^2\\\\\Rightarrow Q=0.8546\times 10^5\\\Rightarrow Q=85.46\ kJ

6 0
3 years ago
You are given two objects of identical size, one made of aluminum and the other of lead. You hang each object separately from a
ollegr [7]

Answer:

Explanation:

Volume of lead object = volume of aluminium object = V

mass of lead object > mass of aluminium object

When both the objects immersed in water, the buoyant force acting on both the objects.

Buoyant force = Volume immersed  x density of water x gravity

As the volume of both the objects is same, so the buoyant force acting on both the objects is same.

So, weight in air of lead object is more than the weight in air of aluminium object.  

7 0
3 years ago
A rectangle has an area measuring 1350 square centimeters. Its length and width are whole numbers of centimeters. What are the p
Aleks04 [339]

The smallest perimeter of the rectangle is of value 150 cm.

Given:

The area of the rectangle, A = 1350 cm²

Calculation:

Let the length of the rectangle be 'x'

      the breadth of the rectangle be 'y'

We know that the area of a rectangle is given as:

A = (x) × (y)  

Applying values in the above equation we get:

xy = 1350 cm²

Factorizing the value of 1350, the possible values of length and breadth of the rectangle is as listed below:

x (cm)         y (cm)

1350      ×       1

675       ×       2

450       ×       3

270       ×       5

225       ×       6

150        ×       9

135        ×       10

90         ×       15

75         ×        18

54         ×        25

50         ×        27

45         ×        30         (least possible value)

Thus, the smallest perimeter of the rectangle can be calculated as:

P = 2 (x + y)

  = 2 (45 + 30)

  = 150 cm

Therefore, the smallest perimeter that the rectangle will have is 150 cm.

Learn more about factorization here:

<u>brainly.com/question/9231261</u>

#SPJ4

7 0
2 years ago
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