2 years ago

Lifting a piano into a truck is an example of doing negative work. A. True B. False

Physics

1 answer:

Elis [28]2 years ago

5 0

Answer:

False

Explanation:

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The basic barometer can be used to measure the height of a building. If the barometric readings at the top and the bottom of a b

erma4kov [3.2K]

Answer:

$h = 269.6 m$

Explanation:

Pressure at the bottom of the building and at the top of the building must be related as

$P_{top} = P_{bottom} - \rho g h$

$P_{top} = 730 mm Hg$

$P_{bottom} = 755 mm Hg$

now we will have

$(755 \times 10^{-3})(13.6 \times 10^3)(9.81) = P_{bottom}$

$P_{bottom} = 1.007 \times 10^5 Pa$

$P_{top} = (730\times 10^{-3})(13.6 \times 10^3)(9.81)$

$P_{top} = 0.974 \times 10^5$

now we have

$(1.007 - 0.974)\times 10^5 = 1.25 (9.81) h$

$h = 269.6 m$

7 0

2 years ago

7. Two children of mass 20 kg and 30 kg sit balanced on a seesaw with the pivot point located at the center of the seesaw. If th

Ainat [17]

Answer:

Explanation:

Given

mass of children $m_1=20\ kg$

$m_2=30\ kg$

distance between two children $L=3\ m$

suppose small child is at a distance of x m from pivot point

so torque of small child and heavier child must be equal

$20\times (x)=30\times (3-x)$

$2x=9-3x$

$5x=9$

$x=1.8\ m$

7 0

3 years ago

A force of 100 newtons is used to move an object a distance of 15 meters with a power of 25 watts. Find the

valentina_108 [34]

work is distance * force so 15*100=1500

and to find time you know power = diastance * force / time

so 25=15*100/t

25=1500/t

25/1500=t

.016=time

5 0

2 years ago

A roller coaster car of mass m= 300 kg is released from rest at the top of a 60 m high hill (position A), and rolls with a negli

Andrews [41]

Answer: The principle of conservation of energy, angular speed and centripetal force

Explanation:

At point A, the car experienced maximum of potential energy

As it moves down the hill, the potential energy decreases while the kinetic energy increases.

The maximum kinetic energy of the car is needed for the attainment of enough centripetal force to help the car move through the loop without falling .

4 0

3 years ago

Which of the following is least likely to be a scientific experiment?

nikitadnepr [17]

D should be the answer

3 0

2 years ago