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3 years ago

Explain and answer plz

Physics

2 answers:

Advocard [28]3 years ago

7 0

Ur ans. is : B AKA 40 %.

iren [92.7K]3 years ago

3 0

If you look at the chart you see that there are 6 kids that spend 4-5 hours on the internet out of a total of 15 so it can be put into a fraction like this: 6/15 if you divide this fraction you will get the decimal form: 0.4 multiply this number by 100 and you get the percent: 40%

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Traumatic brain injury such as concussion results when the head undergoes a very large acceleration. Generally, an acceleration

miss Akunina [59]

Answer:

1728.42857143 m/s²

0.00155883061577 s

259.264285715 m/s²

0.0103922041051 s

The child will get injured if he/she falls on a hardwood floor

Explanation:

t = Time taken

u = Initial velocity

v = Final velocity

s = Displacement

a = Acceleration

g = Acceleration due to gravity = 9.81 m/s²

$v^2-u^2=2gs\\\Rightarrow v=\sqrt{2gs+u^2}\\\Rightarrow v=\sqrt{2\times 9.81\times 0.37+0^2}\\\Rightarrow v=2.69432737432\ m/s$

$v^2-u^2=2as\\\Rightarrow a=\dfrac{v^2-u^2}{2s}\\\Rightarrow a=\dfrac{0^2-2.69432737432^2}{2\times 2.1\times 10^{-3}}\\\Rightarrow a=-1728.42857143\ m/s^2$

Magnitude of deceleration is 1728.42857143 m/s²

$v=u+at\\\Rightarrow t=\dfrac{v-u}{a}\\\Rightarrow t=\dfrac{0-2.69432737432}{-1728.42857143}\\\Rightarrow t=0.00155883061577\ s$

Time taken is 0.00155883061577 s

$v^2-u^2=2as\\\Rightarrow a=\dfrac{v^2-u^2}{2s}\\\Rightarrow a=\dfrac{0^2-2.69432737432^2}{2\times 1.4\times 10^{-2}}\\\Rightarrow a=-259.264285715\ m/s^2$

Magnitude of deceleration is 259.264285715 m/s²

$v=u+at\\\Rightarrow t=\dfrac{v-u}{a}\\\Rightarrow t=\dfrac{0-2.69432737432}{-259.264285715}\\\Rightarrow t=0.0103922041051\ s$

Time taken is 0.0103922041051 s

It is likely that the child will get injured if he/she falls on a hardwood floor.

It is less likely that the child will get injured if he/she falls on a carpeted floor.

7 0

4 years ago

4. A roller coaster starts at the top of a hill, 42 m above ground, with a velocity of 5.0 m/s.

Lady bird [3.3K]

Answer:

A roller coaster starts from rest at a point 45 m above the bottom of a dip (See Fig. 6-2). Neglect friction, what will be the speed of the roller coaster at the top of the next slope, which is 30 m above the bottom of the dip?

a. 17 m/s b. 24 m/s c. 14 m/s d. 30 m/s

You have no mass given, so you work it cancelling the mass:

i'll take g = 9.8 m/s^2

(g x h1) - (g x h2) = 1/2v^2 ( no mass either for KE)

(9.8 x 45) - (9.8 x 30) = 147

147 x 2 = v^2 = 294, sq-rt = v = 17.146 m/s answer (17m/s)

A roller coaster starts with a speed of 5.0 m/s at a point 45 m above the bottom of a dip (See Fig. 6-2). Neglect friction, what will be the speed of the roller coaster at the top of the next slope, which is 30 m above the bottom of the dip? a. 16 m/s b. 12 m/s c. 14 m/s d. 18 m/s

u^2 = 2gh (5^2 = 2gh)

25/(2g) = h = 1.2755 m

45 + 1.2755 = 46.2755m

Do the same equations as question one, answer = 17.86 m/s (answer 18 m/s)

A roller coaster starts at a point 30 m above the bottom of a dip with a speed of 25 m/s (See Fig. 6-2). Neglect friction, what will be the speed of the roller coaster at the top of the next slope, which is 45 m above the bottom of the dip? a. 14 m/s b. 16 m/s c. 20 m/s d. 18 m/s

Do the same! 25^2 = 2gh, 625/(2g) = h = 31.89 m

31.89 + 30 = 61.89 m

(9.8 x 61.89) - (9.8 x 45) = 1/2v^2 = 165.52

165.52 x 2 = 331.04, sq-rt = 18.19 m/s (answer 18 m/s)

A horizontal force of 200 N is applied to move a 55-kg cart (initially at rest) across a 10 m level surface. What is the final speed of the cart?

a. 73 m/s b. 6.0 m/s c. 36 m/s d. 8.5 m/s

Ignoring friction:

F = ma

200/55 = a = 3.636 m/s^2

v^2 = u^2 + 2as, u^2 = zero

v^2 = 2as

2as = 2 x 3.636 x 10 = 72.72, sq-rt = 8.52 m/s (answer 8.5 m/s)

Explanation:

3 0

3 years ago

An object of mass m = 2.9 g and charge Q = +42 µC is attached to a string and placed in a uniform electric field that is incline

Alisiya [41]

(a)
F= qE 

F sin 30.0° = mg 
= 0.0026(10) 
= 0.026 N 
F = 0.052 N 

E = F/q = 0.052 / 60µ = 867 N/C 

(b) 
T = F cos 30.0° 
= 0.0450 N

8 0

3 years ago

Liquid water has surface tension, has a high specific heat, and functions effectively as a solvent for polar covalent and ionica

MrRissso [65]

Answer:

The property to form polar covalent bond and hydrogen bonds

Explanation:

Liquid water exhibits the property of surface tension, functions as solvent for ionic and polar covalent bonded molecules and have high specific heat.

All these properties can be credited to the property of water to form hydrogen bonds with liquid water molecules where the hydrogen bonding results when hydrogen atom of a water molecule is attracted to a more electro negative oxygen atom of other water molecule in the neighborhood while polar covalent bond formation results in the the water molecule as it is a polar covalent molecule as it contains hydrogen atom and an electronegative oxygen atom which results in the charge distribution in the molecule.

3 0

3 years ago

What is the velocity of the girl in Figure b? Please help me!!!! Is the answer A,B,C,D,E, or F?

attashe74 [19]

There is a Blank screen

6 0

3 years ago