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3 years ago

Why can’t you identify a substance on the basis of density alone?

1 answer:

8 0

Because density changes, it do depends on the state of the substance it's a state variable, for eg you have a cup of water at 4°c at this point the water possess the highest density, but at 0°c the density decreases, due to anamolous behaviour of water molecules by creating a cage mechanised structure.. (then according to your statement you might say both are different, but though they are same just difference in thier states) thus you can't have density alone as a basis

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WILL GIVE BRAINLIEST

Vilka [71]

Answer:

4.44m/s

Explanation:

Given parameters:

Number of laps = 4

Length of track = 400m

Time taken = 6min

Unknown:

Average speed = ?

Solution:

The average speed is the total distance covered divided by the time taken.

It is mathematically expressed as;

Average speed = $\frac{total distance}{time taken}$

Total distance = number of laps x length of track = 4 x 400 = 1600m

Now convert the time to seconds;

60s = 1 min

6 minutes will be 6 x 60 = 360s

So;

Average speed = $\frac{1600}{360}$ = 4.44m/s

6 0

2 years ago

A) A car accelerates uniformly at 3.7 m s⁻² as it passes a stationary road train. The initial speed of the car is 30 m s⁻¹, and

Tanya [424]

(a) The length of the train is 54.6 m

(b) The braking distance of the road train is 194.44 m

The given parameters:

acceleration of the car, a = 3.7 m/s²

initial velocity of the car, u = 30 m/s

final velocity of the car, v = 130 km/h = 36.11 m/s

To find:

the length of the train

The length of the train is the distance travelled by the car

The distance traveled by the car is calculated as:

$v^2 = u^2 + 2as\\\\2as = v^2 - u^2\\\\s = \frac{ v^2 - u^2}{2a} \\\\where;\\\\s \ is \ the \ distance \ travelled \ by \ the \ car\\\\s = \frac{(36.11)^2 - (30)^2}{2\times 3.7} \\\\s = 54.585 \ m\\\\s \approx 54.6 \ m$

Thus, the length of the train is 54.6 m

(b) The braking distance of a road train travelling at 25 m s⁻¹

$a = \frac{v_1^2}{2s_1} = \frac{v_2^2}{2s_2} \\\\Given;\\\\s_1 = 70 \ m\\\\v_1 = 15 \ m/s\\\\v_2 = 25 \ m/s\\\\s_2 = ?\\\\2s_2v_1^2 = 2s_1v_2^2\\\\s_2 = \frac{ 2s_1v_2^2}{2v_1^2} \\\\s_2 = \frac{s_1v_2^2}{v_1^2} \\\\s_2 = \frac{70\times 25^2}{15^2} \\\\s_2 = 194.44 \ m$

Thus, the braking distance of the road train is 194.44 m

Learn more here: brainly.com/question/19572178

6 0

2 years ago

A conducting rod (length = 2.0 m) spins at a constant rate of 2.0 revolutions per second about an axis that is perpendicular to

vladimir2022 [97]

Answer:

0.050V

Explanation:

To solve this problem it is necessary to use the concepts related to the potential between two objects that have a magnetic field, this concept is represented in the equation.

$\int dV = \int_{0}^{l/2} Bv (dl)$