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3 years ago

Please need help with this one number 9

Physics

1 answer:

Evgesh-ka [11]3 years ago

7 0

<span>It's A. Individuals with traits NOT suited for survival DON'T pass their traits to their offspring, because they don't survive and they DON'T HAVE OFFSPRING. That's why, after a while, most of the living individuals have traits that ARE suited for survival. THAT's what evolution says. It says nothing about individuals changing. Note this not my answer its the answer of the guy up above who wrote it in the comments instead of in an answer!</span><span />

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Please please help. I don’t understand this.

Kazeer [188]

Which questions do you need help? I could help you

5 0

4 years ago

7. A toy car of mass 1.2 kg is driving vertical circles inside a hollow cylinder of radius 2.0m. It is moving at a constant spee

wlad13 [49]

Answer:

$N_{top}=9.8N\\N_{bottom}=33.4N$

b) $v_{min}=4.4m/s$

Explanation:

The net force on the car must produce the centripetal acceleration necessary to make this circle, which is $a_{cp}=\frac{v^2}{R}$ . At the top of the circle, the normal force and the weight point downwards (like the centripetal force should), while at the bottom the normal force points upwards (like the centripetal force should) and the weight downwards, so we have (taking the upwards direction as positive):

$-m\frac{v^2}{R}=-N_{top}-mg\\m\frac{v^2}{R}=N_{bottom}-mg$

Which means:

$N_{top}=m\frac{v^2}{R}-mg=(1.2kg)\frac{(6m/s)^2}{2m}-(1.2kg)(9.8m/s^2)=9.8N\\N_{bottom}=m\frac{v^2}{R}+mg=(1.2kg)\frac{(6m/s)^2}{2m}+(1.2kg)(9.8m/s^2)=33.4N$

The limit for falling off would be $N_{top}=0$ , so the minimum speed would be:

$0=m\frac{v_{min}^2}{R}-mg\\v_{min}=\sqrt{Rg}=\sqrt{(2m)(9.8m/s^2)}=4.4m/s$

3 0

3 years ago

Mrs. Brown's class is studying magnets and electricity. At the end of the unit Claire states that magnets and electricity are bo

Gwar [14]

Answer:

Magnets can create electricity and electricity can create a magnetic force.

Both electric charges and magnets do not have to touch an object in order to exert a force on it.

Electromagnets use electricity to create a magnetic force.

Explanation:

7 0

3 years ago

Read 2 more answers

Porque fueron tan importantes las aportaciones de Galileo Galilei en la construcción y validación del conocimiento científico

iren [92.7K]

Yooo what? Sorry I’m confused

4 0

3 years ago

A box of books weighing 290 N is shoved across the floor of an apartment by a force of 400 N exerted downward at an angle of 34.

NARA [144]

Answer: 1.95s

Explanation:

Given

ma = 290 cos 34.9 - fk

fk = 290 cos 34.9 - ma

fn = mg + 400 sin Φ

fn = 290 + 400 sin 34.9

fn = 290 + 228.9

fn = 518.9

fk = fn * uk

uk = 0.57

290 cos 34.9 - ma = 518.9 * 0.57

290 cos 34.9 - ma = 295.8

290 cos 34.9 - 295.8 = ma

ma = -58

m = 290/10 = 29

a = 58/29

a = 2

Using equation of motion

S = ut + .5at²

3.8 = 0 + .5*2*t²

3.8 = t²

t = 1.95s

3 0

3 years ago