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3 years ago

How does what happens to the particles in a substance during melting differ from what happens during freezing?

1 answer:

8 0

When in the melting process particles start to move more freely when in the freezing process particles tend to slow and vibrate in place

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A projectile is fired at an upward angle of 29.7Â° from the top of a 108-m-high cliff with a speed of 130-m/s. What will be its

german

Answer:

79.2 m/s

Explanation:

θ = angle at which projectile is launched = 29.7 deg

a = initial speed of launch = 130 m/s

Consider the motion along the vertical direction

v₀ = initial velocity along the vertical direction = a Sinθ = 130 Sin29.7 = 64.4 m/s

y = vertical displacement = - 108 m

a = acceleration = - 9.8 m/s²

v = final speed as it strikes the ground

Using the kinematics equation

v² = v₀² + 2 a y

v² = 64.4² + 2 (-9.8) (-108)

v = 79.2 m/s

5 0

3 years ago

Assume that the upward direction is positive and the downward direction is negative. What is the ball's velocity (in m/s) when i

LenaWriter [7]

The given question is incomplete. The complete question is as follows.

You throw a ball vertically upward, and as it leaves your hand, its speed is 26.0 m/s.

(a) How high (in m) does it rise above the level where it leaves your hand?

(b) How long (in s) does it take to reach its highest point?

(c) How long (in s) does the ball take to return to the level where it left your hand after it reaches its highest point?

(d) Assume that the upward direction is positive and the downward direction is negative. What is the ball's velocity (in m/s) when it returns to the level where it left your hand? (Indicate the direction with the sign of your answer.)

Explanation:

(a) For maximum height, the formula will be as follows.

$v^{2} = u^{2} + 2as$

a = $v^{2} - 2gh$

or, h = $\frac{v^{2}}{2g}$

= $\frac{(26)^{2}}{2 \times 9.8}$

= $\frac{676}{19.6}$

= 34.5 m/s

Hence, it rises 34.5 m/s above the level where it leaves your hand.

(b) Time to reach maximum height is as follows.

v = u + at

or, v - gt = 0

t = $\frac{v}{g}$

= $\frac{26}{10}$

= 2.6 sec

Therefore, it will take 2.6 sec to reach its highest point.

(c) Time taken by the ball to ascent is equal to the time it has taken to descent.

Therefore, time taken by the ball to return to the level where it left your hand after it reaches its highest point? is also 2.6 sec.

(d) Speed of the ball will be 26 m/s in the downward direction. Hence, the velocity will be -26 m/s.

3 0

3 years ago

Vector A has a magnitude of 4.0m and points 30 south of east vector B has a magnitude of 2.0m and points 30 north of west the re

valentina_108 [34]

Answer:

2.06 m at 49.7 or 50 degree South of East

Explanation:

take x axis and y axis and follow as explained in attachment

Download pdf

6 0

3 years ago

A sample with a path length of 1 cm absorbs 99.0% of the incident light at a wavelength of 274 nm, measured with respect to an a

Ksju [112]

Answer:

17. NADH has a molar extinction coefficient of 6200 M2 cm at 340 nm. Calculate the molar concentration of NADH required to obtain an absorbance of 0.1 at 340 nm in a 1-cm path length cuvette. 18. A sample with a path length of 1 cm absorbs 99.0% of the incident light at a wavelength of 274 nm, measured with respect to an appropriate solvent blank. Tyrosine is known to be the only chromophore present in the sample that has significant absorption at 274 nm. Calculate the molar concentration of tyrosine in the sample.

Explanation:

8 0

3 years ago

a circuit element having terminals a and b has vab = 10v and iba = 2a over a period of 20s, how much charge moves throught the e

PIT_PIT [208]

Answer: charge Q = 40Coulombs

Explanation: The current in a circuit is the quantity of charge that flows through it per second.

Here the 2amp current is same as the amount of charge in coulomb that flows through the terminal in ONE second.

So, if 2 coulomb of charge flows in 1sec then in 20 secs we will have

Q(charge) = 2*20 = 40 coulombs

6 0

3 years ago