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4 years ago

HELP ASAPPPPPPPP!!!!!worth 100 points

Physics

2 answers:

ivolga24 [154]4 years ago

4 0

Sally walks 10 meters forward and then 5 meters backwards.

forward + backward -

displacement= +10 -5 = +5

distance= 10 + 5 = 15

15-5=10m

so B) Sally's displacement is 10m less than her distance travelled.

Free fall is a situation in which the only force acting upon an object is gravity. force=massxacceleration n gravity force=massx gravity acceleration

so acceleration=gravity acceleration=constant.

ans is B) acceleration due to gravity is always the same

podryga [215]4 years ago

3 0

Displacement is a vector which means it has direction and can have positive or negative values. Distance is a scalar which means it has no direction and positive only.

Sally walks 10 meters forward and then 5 meters backwards. Forward is postive and backward is negative. Her displacement is +10+(-5) = +5m and her distance is 10+5=15m. So the answer is B) Sally's displacement is 10m less than her distance travelled.

Newton 2nd law states that force = ma. In free fall, the only force is gravity force which is equal to mg where g is gravitational acceleration. The acceleration is always the same because B) acceleration due to gravity is always the same.

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solong [7]

6. f = 128.62 $s^{-1}$ , T= 0.0077775 s

7. f = 2.2 * $10^{4}$ $s^{-1}$ , T = 4.545 * $10^{-5}$ s

8. 32.64 $s^{-1}$

9. 3.29 * $10^{14}$ $s^{-1}$

Explanation:

Step 1:

For light and sound v = fλ

where v represents the velocity

f represents the frequency

λ represents the wavelength

λ = 2.69 m

v = 346 m/s

f = v/λ = 346/2.69 = 128.62 $s^{-1}$

Time period is the reciprocal of frequency

T = 1/128.62 = 0.0077775 s

Step 2:

λ = 110 cm = 1.1 m

v = 2.42* $10^{4}$ m/s

f = 2.42* $10^{4}$ /1.1 = 2.2 * $10^{4}$ $s^{-1}$

T = 1/(2.2* $10^{4}$ ) = 4.545 * $10^{-5}$ s

Step 3:

λ = 10.6 m

v = 346 m/s

f = v/λ = 346/10.6 = 32.64 $s^{-1}$

Step 4:

λ = 5.89 * $10^{-7}$ m

v = 1.94 * $10^{8}$ m/s

f = v/λ = 3.29 * $10^{14}$ $s^{-1}$

8 0

4 years ago

A train A travelled a distance of 150 km in 3 hours, whereas, train 'B"

ozzi

Answer:

Therefore, Train A is faster with 50km/h and a 5km/h difference

Explanation:

train A

150km/3h = 50km/h

train B

180km/4h = 45km/h

8 0

3 years ago

The system needs an ordinary friction-based brake to bring the train to a full stop. Explain why the magnetic brake is not very

BabaBlast [244]

Answer:

The slower the train is moving, the less are the changes of the magnetic flux, thus the eddy currents become weaker.

Explanation:

A magnetic brakes is not a very efficient way of braking when a train is moving slowly because at low speeds, the changes in the magnetic flux are very less and so it causes the eddy current to become weaker.

Let us find the drag force which is proportional to the velocity of two conducting plates.

The EMF that is induced in the eddy currents are : $E=v(B \times L)$

The force which is due to the induced magnetic field is, $F=l(L \times B)$

Therefore, $F=\frac{E}{R} \times (L \times B)$

$F=\frac{v(B \times L)}{R} \times (L \times B)$

Here, force is directly proportional to the velocity of the two conducting plates.

Therefore, we can say that when the speed of the train is low, the magnetic flux changes are less and thus the eddy currents are weaker.

6 0

3 years ago

A large negatively charged object is placed on a wooden table. A neutral metallic ball rolls straight towards the object but sto

bazaltina [42]

Answer:

the charge of each small sphere, which is + Q / 2

Explanation:

For this exercise we must use the fact that a charged object induces charges on nearby bodies

Induced charge comes from the fact that charges of the same sign repel and charges of different signs attract.

In this case the large, fixed ball with a -Q charge induces a positive charge in the nearest part and the negative charges are repelled to the furthest point, but the net charge on the metallic sphere remains zero. It should be emphasized that since the charges are of different signs, there is an attractive force between the two spheres.

This first metallic sphere now has a negative charge on the back, this charge induces a positive charge on the second sphere, as the charges are of a different sign, they attract each other, which is why the force is attractive.

When the first sphere stops the second sphere hits it, at this moment the charge of the two spheres is equal, therefore the induced charge in the two spheres is + Q. When the two spheres are separated, the charge on each of them is half, that is, the sphere has a charge + Q / 2 and the second sphere has a charge + Q / 2.

Therefore the first sphere is subjected to two forces: an attractive force with the large sphere of charge -Q and a repulsive force with the second sphere of charge + Q / 2.

So the first sphere must approach the big ball and the second sphere must move away from the big sphere.

This is the process of the movement of this exercise, unfortunately the statements with which to compare this process do not appear, but one of the most common questions of what is the charge of each small sphere, which is + Q / 2

4 0

3 years ago

Lottery balls are thrown into a hopper and are set into motion by air forced through the container. each ball has a mass of 0.00

Marina CMI [18]

In this three body system total kinetic energy remains constant:
$E_{k} = constant =0.0268 J$

$E_{k} = E_{k1}+ E_{k2}+ E_{k3}$
If we assume that upwards movement is positive and downwards movement is negative the formula is:
$E_{k} = E_{k1}- E_{k2}+ E_{k3}$

Formula for kinetic energy is:
$E_{k} = \frac{m v^{2} }{2}$

Now we have:
$E_{k} = \frac{m v_{1} ^{2} }{2} -\frac{m v_{2} ^{2} }{2} +\frac{m v_{3} ^{2} }{2} \\ E_{k} = \frac{m}{2} (v_{1} ^{2}-v_{2} ^{2}+v_{3} ^{2}) \\ \\ 0.0268= \frac{0.0044}{2} (1.3 ^{2}-1.66^{2}+v_{3} ^{2}) \\ \\ 0.0536=0.0022(1.69-2.7556+v_{3} ^{2}) \\ \\ v_{3} ^{2}=25.43 \\ \\ v_{3} =+-5.04$

We got two solutions: positive and negative. The speed is 5.04 m/s and direction can be upwards and downwards.

3 0

3 years ago

HELP ASAPPPPPPPP!!!!!***worth 100 points***

HELP ASAPPPPPPPP!!!!!worth 100 points