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an ice skater, standing at rest, uses her hands to push off against a wall. she exerts an average force on the wall of 120 N and the push lasts 0.8 seconds. The skater's mass is 55 kg. what is the skater's speed after she stops pushing on the wall

Answers

Answer 1

Answer:

Answer:

The skater's speed after she stops pushing on the wall is 1.745 m/s.

Explanation:

Given that,

The average force exerted on the wall by an ice skater, F = 120 N

Time, t = 0.8 seconds

Mass of the skater, m = 55 kg

It is mentioned that the initial sped of the skater is 0 as it was at rest. The change in momentum of skater is :

$\Delta p=m(v-u)\n\n\Delta p=mv$

The change in momentum is equal to the impulse delivered. So,

$J=\Delta p=F* t\n\nmv=F* t\n\nv=(Ft)/(m)\n\nv=(120* 0.8)/(55)\n\nv=1.745\ m/s$

So, the skater's speed after she stops pushing on the wall is 1.745 m/s.

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If I am given a total capacitence of two capacitors, their capacitence togather is 22 F. What capacitence would the individual capacitors have if they are connected in parallel or connected in series.

Answers

Answer:

In parallel combination, the capacity of each capacitor is 11 F.

In series combination, the capacity of each capacitor is 44 F.

Explanation:

Let there are two capacitors each of capacitance C.

When they are connected in parallel:

In parallel combination, the effective capacitance is Cp.

Cp = C1 + C2 = C + C

22 = 2 C

C = 11 F

When they are connected in series:

In parallel combination, the effective capacitance is Cs.

1 / Cs = 1 / C1 + 1 / C2 = 1 / C + 1 / C = 2 / C

1 / 22 = 2 / C

C = 44 F

An earthquake on the ocean floor produced a giant wave called a tsunami. The tsunami traveled through the ocean and hit a remote island, causing a lot of damage. Is the water that hit the island the same water that was above the earthquake on the ocean floor?A No, the water from above the earthquake stayed in the same place and only the energy was transferred.
B No, the energy in the wave pushed the water particles from above the earthquake in the opposite direction.
C Yes, the water particles moved toward the island while the energy remained above the earthquake.

Answers

A lot of the biology particles can be certified by a sphychiatrist that can determine weather they are infected with Ebola

Suppose there are 10,000 civilizations in the Milky Way Galaxy. If the civilizations were randomly distributed throughout the disk of the galaxy, about how far (on average) would it be to the nearest civilization?

Answers

Here is the full question

(Hint: Start by finding the area of the Milky Way's disk, assuming that it is circular and 100,000 light-years in diameter. Then find the average area per civilization, and use the distance across this area to estimate the distance between civilizations.)

Answer:

1000 light-years (ly)

Explanation:

If we go by the hint; The area of the disk can be expressed as:

$A = \pi ((D)/(2))^2$

where D = 100, 000 ly

Let's divide the Area by the number of civilization; if we do that ; we will be able to get 'n' disk that is randomly distributed; so ;

$d= (A)/(N) =(\pi ((D)/(2))^2 )/(10, 000)$

The distance between each disk is further calculated by finding the radius of the density which is shown as follows:

$d = \pi r^2 e$

$r^2_e= (d)/(\pi)$

$r_e = \sqrt{(d)/(\pi) }$

replacing d = $(\pi ((D)/(2))^2 )/(10, 000)$ in the equation above; we have:

$r_e = \sqrt{((\pi ((D)/(2))^2 )/(10, 000))/(\pi) }$

$r_e = \sqrt{(((D)/(2))^2 )/(10, 000)}$

$r_e = \sqrt{(((100,000)/(2))^2 )/(10, 000)}$

$r_e = 500 ly$

The distance (s) between each civilization = $2(r_e)$

= 2 (500 ly)

= 1000 light-years (ly)

g A particular guitar string has a length of 60.0 cm, and a mass per unit length of 2.00 grams/meter. You hear a pure tone of 660 Hz when a particular standing wave, represented by the animation above, is excited on the string. Calculate the wavelength of this standing wave.

Answers

Answer:

wavelength of the standing wave will be equal to 30 cm

Explanation:

We have given length of the guitar string L = 60 cm

Mass per unit length $\mu =2gram/m$

Frequency is given f = 660 Hz

We have to find the wavelength of the standing wave

Length of the string will be 2 times of the wavelength of the wave

So $L=2\lambda$

$\lambda =(L)/(2)=(60)/(2)=30cm$

So wavelength of the standing wave will be equal to 30 cm

g During a collision with a wall, the velocity of a 0.4 KgKg ball changes from 25 m/sm/s towards the vall to 12 m/sm/s away from the wall. If the time the ball was in contact with the call was 0.5 secsec , what was the magnitude of the avarage force applied to the ball

Answers

Answer:

F = 10.8N

Explanation:

Given the mass m = 0.4kg, v1 = 25m/s, v2 = 12m/s and t =0.5s

From Newtown's second law of motion the average force can be found. This law states that the product of the force experienced by a body and the time t of the force acting on the body is equal to the change in momentum of the body. Mathematically it can be stated as follows

F×t = m(v2 – v1)

F = m(v2 – v1)/t = 0.4(25 – 12)/0.5 = 10.8N

Which describes one feature of the image formed by a convex mirror?????

Answers

Answer:

The image formed by a convex mirror will always have its smaller than the size of the object no matter what the position of the object.

Explanation:

The image formed by a convex mirror will always have its smaller than the size of the object no matter what the position of the object.

Also notice that convex mirror always makes virtual images.

Another feature of the convex mirror is that an upright image is always formed by the convex mirror.

An important mirror formula to remember which is applicable for both convex and mirrors

1/f= 1/u + 1/v

Here:

'u' is an object which gets placed in front of a spherical mirror of focal

length 'f' and image 'u' is formed by the mirror.

Answer:

right side up

Explanation:

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