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3 years ago

Please help me, I will give BRAINLIEST to the best answer

Physics

2 answers:

In-s [12.5K]3 years ago

8 0

Answer:

I believe it is A, B, and D

Explanation:

It asks you which of the following is having work DONE on IT. When you lift up the grocery bag, you have work done on the grocery bag. When a crane moves dirt, the crane is having work done on the dirt. and in D, I thought if it really counts, but I believe it does since you push the crate along the floor I guess. I'm sure about A and B, not that sure about D though. Have a noice day!

sdas [7]3 years ago

3 0

Explanation:

a. A grocery bag as you lift it up

b. A crane moving dirt......

d. A crate as you push it along the floor

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Electrical energy is used to turn the blades of a fan. The amount of energy transformed is seen here: 750 j electrical energy is

MAVERICK [17]

Here is the energy that is left after the quantity of energy is transformed: 750 j of electrical energy is changed into 400 j of kinetic or mechanical energy, which is then turned into 0.32 j of efficient energy.

To run the fan, electrical energy is utilized.

Here, under the specified circumstances, 750 J of electrical energy is utilized to operate the fan, which is transformed into 400 J of kinetic energy. As a result, 350 J of energy is wasted due to various frictional and resistive losses.

Therefore, we may conclude that only 400 J of the 750 J available energy is used to power the fan, with the remaining energy being wasted as a result of friction.

Additionally, we can state that this fan's effectiveness will be

n = Useful ÷ Total

n = 400 ÷ 750

n = 8 ÷ 25

n = 0.32

Learn more about energy at

brainly.com/question/15915007?referrer=searchResults

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4 0

9 months ago

A plane travels 350 km south along a straight path with an average velocity of 125 km/h to the south. The plane has a 30 minute

faust18 [17]

Average Velocity = Total Displacement / Total time

1st part of journey, 350 km at velocity 125 km/h

Time = 350 / 125 = 2.8 hours.

2nd part of journey, 220 km at velocity 115 km/h

Time = 220 / 115 = 1.9 hours

Average Velocity = Total Displacement / Total time

= (350 + 220) / (2.8 + 1.9)

= 570 / 4.7 ≈ 121.3 km/hr

Average Velocity ≈ 121 km/hr due south.

Option C.

6 0

2 years ago

PLS ANSWER FAST WILL GIVE BRAINLEST!!

egoroff_w [7]

Answer:

from

force =mass x acceleration

mass = force/acceleration

m = f/a

m = 7.5/15

m=0.5kg

3 0

3 years ago

Read 2 more answers

System A has masses m and m separated by a distance r; system B has masses m and 2m separated by a distance 2r; system C has mas

Anna [14]

Answer:

System D --> System C --> System A --> System B

Explanation:

The gravitational force between two masses m1, m2 separated by a distance r is given by:

$F=G \frac{m_1 m_2}{r^2}$

where G is the gravitational constant. Let's apply this formula to each case now to calculate the relative force for each system:

System A has masses m and m separated by a distance r:

$F=G\frac{m \cdot m}{r^2}=G \frac{m^2}{r^2}$

system B has masses m and 2m separated by a distance 2r:

$F=G\frac{m \cdot 2m}{(2r)^2}=G \frac{2m^2}{4r^2}=\frac{1}{2} G \frac{m^2}{r^2}$

system C has masses 2m and 3m separated by a distance 2r:

$F=G\frac{2m \cdot 3m}{(2r)^2}=G \frac{6m^2}{4r^2}=\frac{3}{2} G \frac{m^2}{r^2}$

system D has masses 4m and 5m separated by a distance 3r:

$F=G\frac{4m \cdot 5m}{(3r)^2}=G \frac{20m^2}{9r^2}=\frac{20}{9} G \frac{m^2}{r^2}$

Now, by looking at the 4 different forces, we can rank them from the greatest to the smallest force, and we find:

System D --> System C --> System A --> System B

5 0

3 years ago

A rock falls from rest off a cliff and hits the ground in 2 seconds. If there is no air resistance, determine the rock's velocit

mihalych1998 [28]

Answer:

19.6m/s

Explanation:

A Rock falling off a cliff can be modeled as an object starting with zero velocity moves with constant acceleration for certain period of time, for such motion following equation of motion can be used.

$v(t) = v_{0} +at$

here in our case $v_{0} =0$ because object starts off from rest and $a = g =9.8m/s^2$ is acceleration because of gravity ( Motion under gravity).

and of course t = 2 second.

Now by substituting all this information in equation of motion we get.

$v(2s) = 0+9.8m/s^2 *2s = 19.6m/s$

that would be the velocity of rock as it would hit the ground.

Note! We have assumed that there is no air resistance.

A rock falling off a cliff can be modeled as an object starting with zero velocity moves with constant acceleration for a certain period of time, for such motion following equation of motion can be used.

here in our case because object starts off from rest and is acceleration because of gravity ( Motion under gravity).

and of course t = 2 seconds.

Now by substituting all this information in equation of motion we get.

V = 19.6m/s

that would be the velocity of rock as it would hit the ground.

Note! We have assumed that there is no air resistance.

5 0

3 years ago