Why does sodium chloride and magnesium chloride conduct electricity?

8.) If a car moving at 50km/h skids 15m with locked brakes, how far does the same car moving at 100km/h

pantera1 [17]

(8) A car starting with a speed v skids to a stop over a distance d, which means the brakes apply an acceleration a such that

0² - v² = 2 a d → a = - v² / (2d)

Then the car comes to rest over a distance of

d = - v² / (2a)

Doubling the starting speed gives

- (2v)² / (2a) = - 4v² / (2a) = 4d

so the distance traveled is quadrupled, and it would move a distance of 4 • 15 m = 60 m.

Alternatively, you can explicitly solve for the acceleration, then for the distance:

A car starting at 50 km/h ≈ 13.9 m/s skids to a stop in 15 m, so locked brakes apply an acceleration a such that

0² - (13.9 m/s)² = 2 a (15 m) → a ≈ -6.43 m/s²

So the same car starting at 100 km/h ≈ 27.8 m/s skids to stop over a distance d such that

0² - (27.8 m/s)² = 2 (-6.43 m/s²) d → d ≈ 60 m

(9) Pushing the lever down 1.2 m with a force of 50 N amounts to doing (1.2 m) (50 N) = 60 J of work. So the load on the other end receives 60 J of potential energy. If the acceleration due to gravity is taken to be approximately 10 m/s², then the load has a mass m such that

60 J = m g h

where g = 10 m/s² and h is the height it is lifted, 1.2 m. Solving for m gives

m = (60 J) / ((10 m/s²) (1.2 m)) = 5 kg

(10) Is this also multiple choice? I'm not completely sure, but something about the weight of the tractor seems excessive. It would help to see what the options might be.

4 0

3 years ago

Pls help ASAP this questions are science questions ( biology chemistry physics)

Vilka [71]

Answer:

It would be A.

Explanation:

The scale goes from 0 to 14, With 0 being acidic and 14 being basic.

So if 7 is neutral, then anything less than 7 is moving more towards being more acidic. Anything higher than 7 is moving towards being more basic.

4 0

3 years ago

Read 2 more answers

Which statement explains why a red rose does not appear to be orange?

navik [9.2K]

Answer:

A

Explanation:

you see red because it's reflected and other colors are absorbed, light transmitted through something is when it travels through something like glass or a gem

7 0

3 years ago

Three boys of equal strength try to break a rope (and fail) by tying one end to a fence post and tugging on the other end. Three

podryga [215]

The best choice would be C. Keep one end of the rope tied to the post and have all six boys tug on the other end.

Reason:

A is not correct since in the first case which is B, untying the rope from the post and have 3 boys on each end of it tug, will provide equal or a near equal amount of tension since the boys are all within the same strength, however there can be variables that will affect the tension.

That means B would be true according to A, and then for C, having all six boys pull on the other end of the rope would provide greater tension, since if 3 boys of the same strength range can't break the rope when its tied to the fence, we add the other 3 boys of the same strength.

However, if 3 boys are on each end of the rope and of the same strength then the rope will not break since there is an equal amount of net force exerted on the rope.

We know that the fence can withstand the strength of 3 boys but if we add the other 3 boys then it could provide us with a different outcome.

3B < F

3B(2) ≥ F

So, therefore, our best choice would be C since A and B is incorrect.

4 0

3 years ago

Three blocks are placed in contact on a horizontal frictionless surface. A constant force of magnitude F is applied to the box o

Lina20 [59]

Answer:

A) M

Explanation:

The three blocks are set in series on a horizontal frictionless surface, whose mutual contact accelerates all system to the same value due to internal forces as response to external force exerted on the box of mass M (Newton's Third Law). Let be F the external force, and F' and F'' the internal forces between boxes of masses M and 2M, as well as between boxes of masses 2M and 3M. The equations of equilibrium of each box are described below:

Box with mass M

$\Sigma F = F - F' = M\cdot a$