How many neutrons does element X have if it’s atomic number is 28 and it’s mass number is 81?

A spring on a horizontal surface can be stretched and held 0.2 m from its equilibrium position with a force of 16 N. a. How much

nekit [7.7K]

Answer:

a $W_{3.5} = 490 \ J$

b $W_{2.5} = 250 \ J$

Explanation:

Generally the force constant is mathematically represented as

$k = \frac{F}{x}$

substituting values given in the question

=> $k = \frac{16}{0.2}$

=> $k = 80 \ N /m$

Generally the workdone in stretching the spring 3.5 m is mathematically represented as

$W_{3.5} = \frac{1}{2} * k * (3.5)^2$

=> $W_{3.5} = \frac{1}{2} * 80 * (3.5)^2$

=> $W_{3.5} = 490 \ J$

Generally the workdone in compressing the spring 2.5 m is mathematically represented as

$W_{2.5} = \frac{1}{2} * k * (2.5)^2$

=> $W_{2.5} = \frac{1}{2} * 80 * (2.5)^2$

=> $W_{2.5} = 250 \ J$

5 0

3 years ago

Physics questions , will give brainliest

creativ13 [48]

The applicable relationship here is

... acceleration = rate of change of velocity

4. The slope of the velocity curve is constant, so the acceleration is constant. That slope is 3 m/s in 5 s, or (3 m/s)/(5 s) = (3/5) m/s² = 0.6 m/s²

7. You're looking for a point on the velocity curve where its slope is -2 m/s². That will be somewhere between t=0 and t=4, because slope is positive for t>4. The only available choice in that region is t = 2 s.

8. At 6.00 m/s² for 3 seconds, velocity will change (3 s)×(6.00 m/s²) = 18.00 m/s. That would get you from an initial speed of 3.44 m/s to 21.44 m/s, so clearly 3 s is almost right, but a little too long for the given change in velocity. The best choice is 2.91 s.

If you want to actually figure it out, the change in velocity is 20.9 -3.44 = 17.46 m/s. Using the relation a = ∆v/∆t, we can rearrange it to ∆t = ∆v/a, or

... ∆t = (17.46 m/s)/(6 m/s²) = 2.91 s

9. This problem combines the determination of acceleration with a units conversion problem. Numbers in the problem are given in kph and seconds, and answers are given in m/s². At some point, you need to convert from km/h to m/s. The multiplier for that is (1000 m/km)/(3600 s/h) = 1/3.6 (m·h)/(km·s).

Your change in speed is -24.6 km/h = (1/3.6)·(-24.6) m/s ≈ -6.8333 m/s. When that change in speed occurs over 3.56 seconds, the acceleration is

... (-6.8333 m/s)/(3.56 s) ≈ -1.919 m/s² ≈ -1.92 m/s²

5. At 10 s, the velocity is about 14 m/s. Looking for grid points the curve goes through, we can use (11, 16) and (9, 12). That is, over the 2-second range from 9 s to 11 s, the velocity increases 4 m/s from 12 m/s to 16 m/s. The acceleration is

... ∆v/∆t = a = (4 m/s)/(2 s) = 2 m/s²

6. ∆v/∆t = a = (28 m/s - 0 m/s)/(4.22 s) ≈ 6.6351 m/s² ≈ 6.64 m/s²

10. No change in velocity means the acceleration is 0 m/s².

4 0

3 years ago

Identify two everyday phenomena that exhibit diffraction of sound and explain how diffraction of sound applies. Identify two eve

Naya [18.7K]

Answer:

Explanation:

Diffraction is the term used to describe the bending of a wave around an obstacle. It is one of the general properties of waves.

1. Diffraction of sound is the bending of sound waves around an obstacle which propagates from source to a listener. Two of the daily phenomena that exhibit diffraction of sound are:

i. The voices of people talking outside a building can be heard by those inside.

ii. The sound from the horn of a car can be heard by people at certain distances away.

When sound waves are produced, the surrounding air molecules are required for its transmission. This is because sound wave is a mechanical wave which requires material medium for its propagation. When a source produces a sound, the sound waves bend around obstacles on its path to reach listeners.

2. Light waves are electromagnetic waves which can undergo diffraction. Diffraction of light is the bending of the rays of light around an obstacle. Two of the daily phenomena that exhibit diffraction of light are:

i. The shadow of objects which has the umbra and penumbra regions.

ii. The apparent color of the sky.

A ray of light is the path taken by light, and the combination of two or more rays is called a beam. A ray or beam of light travels in a straight line, so any obstacle on its path would subject the light to bending around it during propagation. These are major applications in pin-hole cameras, shadows, rings of light around the sun etc.

Some significant differences between diffraction of light and that of the sound are:

i. Diffraction of light is not as common as that of sound.

ii. Sound propagates through a wider region than light waves.

iii. Sounds are longitudinal waves, while lights are transverse waves.

7 0

4 years ago

What do "Newton's apple" and the moon have in common?

SVEN [57.7K]

Answer:

Both these motions are caused by the Gravitational force of earth.

Explanation:

Both these motions are caused by the Gravitational force of earth.

6 0

3 years ago

Three liquids that do not mix are poured into a cylindrical container with a diameter of 10.0 cm. The densities and volumes of t

kipiarov [429]

Answer:

P = 9622.9 Pa = 9.62 KPa

Explanation:

First, we will calculate the mass of all three liquids:

m = ρV

where,

m = mass of liquid

ρ = density of liquid

V = Volume of liquid

FOR LIQUID 1:

m₁ = (2.8 x 10³ kg/m³)(2 x 10⁻³ m³) = 5.6 kg

m₂ = (1 x 10³ kg/m³)(1.5 x 10⁻³ m³) = 1.5 kg

m₃ = (0.6 x 10³ kg/m³)(1 x 10⁻³ m³) = 0.6 kg

The total mass will be:

m = m₁ + m₂+ m₃ = 5.6 kg + 1.5 kg + 0.6 kg

m = 7.7 kg

Hence, the weight of the liquids will be:

W = mg = (7.7 kg)(9.81 m/s²) = 75.54 N

Now, we calculate the base area:

A = πr² = π(0.05 m)²

A = 7.85 x 10⁻³ m²

Now the pressure will be given as:

$P = \frac{F}{A}\\\\P = \frac{75.54\ N}{7.85\ x\ 10^{-3}\ m^2}$

5 0

3 years ago