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Ann [662]
3 years ago
11

What is needed for work to be done?

Physics
1 answer:
nlexa [21]3 years ago
8 0

Answer:

a force must be act on an object while an equal force acts oppositely on the object.

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A 780g, 50-cm-long metal rod is free to rotate about a frictionless axle at one end. While at rest, the rod is given a short but
Semmy [17]

Answer:

9.6 rad/s

Explanation:

L = length of the metal rod = 50 cm = 0.50 m

M = Mass of the long metal rod = 780 g = 0.780 kg

Moment of inertia of the rod about one end is given as

I = \frac{ML^{2}}{3} = \frac{(0.780)(0.50)^{2}}{3} = 0.065 kgm^{2}

F = force applied by the hammer blow = 1000 N

Torque produced due to the hammer blow is given as

\tau = \frac{FL}{2}

\tau = \frac{(1000)(0.50)}{2}

\tau = 250 Nm

t = time of blow = 2.5 ms = 0.0025 s

w = Angular velocity after the blow

Using Impulse-change in angular momentum, we have

I w = \tau t\\(0.065) w = (250) (0.0025)\\w = 9.6 rads^{-1}

5 0
3 years ago
A certain dam generates 120 MJ of mechanical (hydroelectric) energy each minute. If the conversion from mechanical to electrical
Karolina [17]

Answer:

electric energy ( power ) = 300000 W

Explanation:

given data

mechanical (hydroelectric) energy = 120 MJ/min = 2000000 J/s

efficiency = 15 % = 0.15

solution

we know that Efficiency of electric engine is expression  as

Efficiency = Mechanical energy ÷ electric energy  ......................1

and here dam electrical power output is

put here value in equation 1

electric energy ( power ) = Efficiency × Mechanical energy ( power )

electric energy ( power ) = 0.15 × 2000000 J/s

electric energy ( power ) = 300000 W

8 0
3 years ago
PLS HELP:)
Monica [59]
The incident ray will have an angle of reflection of 30 degrees (made with a surface normal to the mirror surface). The reflected ray will make an angle of 60 degrees (90 - 30 degrees) with the mirror surface.
6 0
3 years ago
If the earth makes one orbit around the sun what is it called
vazorg [7]

then its called a year! when the earth orbits around the sun in 356 or 366 days its called a year

8 0
4 years ago
Why will a delivery truck filled with birds sitting on its floor be heavier than a truck with the same birds flying around insid
34kurt

The reason why a delivery truck filled with birds sitting on the floor be heavier than a truck with the same birds flying around is because when the birds are sitting on the floor, they are adding their weight to the truck.

Meanwhile, if the birds are flying around they aren't resting on the truck or touching it, so therefore their weight wouldn't be added to the truck.

The mass of the truck will remain the same as you cannot change the mass but the weight will vary depending on the items and objects placed in it.

4 0
3 years ago
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