The net force of a heavy, stationary box is?

Match the following:

Nadusha1986 [10]

Answer:

Statement 1 can be matched with option f (Van der waal forces)

Statement 2 can be matched with option b (Liquid crystal)

statement 3 can be matched with option e (Thermal expansion)

Statement 4 can be matched with option g (Viscosity)

Statement 5 can be matched with option b (Fractional distillation)

Statement 6 can be matched with option a (Diffusion)

Statement 7 can be matched with option d (Miscible)

Explanation:

Van der waal forces are weak inter-molecular bonds found between covalent molecules e.g molecules of graphite, noble gases etc
Liquid crystals are substances that behave like liquids and its molecules orientate itself like a crystal (solid). They can be referred to as LCs.
Thermal expansion is a phenomenon where by matter changes in shape, volume and area due to a change in temperature.
Viscosity is a term used to describe a fluid's resistance to flow. It is also used to describe the internal friction that a moving liquid experiences. Oil is more viscose than liquid water
Fractional distillation is a separation technique used in separating two or more miscible liquids of close boiling points. For example petrol and diesel oil can be separated using fractional distillation. An industrial application of this technique is Fractional distillation of crude oil where crude oil is separated into its components
Diffusion is the movement of dissolved particles, gases, liquid from a region of higher concentration to a region of lower concentration until there is a equal balance. This can occur when you spray a perfume in one end of a room. You will get to smell the perfume at the other end after some time. Diffusion is fastest in gas as compared to liquids and solids.
Miscible is a word used to describe liquids forming a homogeneous mixture when dissolved in each other. Miscibility is factor to be considered when separating mixture.

7 0

3 years ago

the minimum flying speee for a bird called a house martin is 9.0ms^-1. it reaches this speed by falling from its nest before swo

Lilit [14]

Answer:

The nest must be about 4.15 meters above ground

Explanation:

Use the velocity equation under accelerated motion (acceleration of gravity ):

$v_f=v_i+a\,*\,t$

which for this case has initial velocity = 0 (falls from the nest), final velocity = 9 m/s, and a = 9.8 m/s^2, then we can find the time needed in air while falling to reach the required speed:

$v_f=v_i+a\,*\,t\\9=0+9.8\,t\\t=\frac{9}{9.8} \, sec\\t \approx 0.92\,\, sec$

We now use this time value to find the distance covered in free fall during 0.92 seconds:

$d=\frac{1}{2} \,9.8 \,t^2=4.9\,(0.92)^2=4.147 \,meters\approx 4.15\,meters$

8 0

3 years ago

Calculate the potential energy of a five KG object sitting at the top of a 2 m ramp

docker41 [41]

5 x 10 x 200 = 10000

5 0

3 years ago

A pendulum bob is given velocity u =

Mama L [17]

Answer:

V = P = 0 m/s

Explanation:

When a pendulum bob is given an initial displacement or the initial velocity, it starts to execute periodic motion or simple harmonic motion. During this motion the kinetic and potential energy keeps interconverting. The kinetic energy becomes maximum at the lowest point, that is the mean point. Hence, the velocity is maximum at this point, as well. Similarly, at both extreme positions the potential energy becomes maximum due to maximum height, while the kinetic energy becomes zero at the highest point, that is extreme positions. At these, positions the velocity will be minimum and it will be zero due to zero kinetic energy. Hence, at both extreme positions the bob stops momentarily before, reversing the direction. Hence,

7 0

3 years ago

An object moves at 60 m/s in the +x direction. As it passes through the origin it gets a 4.5 m/s^2 acceleration in the -x direct

Brut [27]

Answer:

a) After 26.67 seconds it returns back to the origin

b) Velocity when it returns to the origin = 60 m/s in the -x direction

Explanation:

a) Let the starting position be origin and time be t.

After time t displacement, s = 0 m

Initial velocity, u = 60 m/s

Acceleration, a = -4.5 m/s²

We have equation of motion s = ut + 0.5 at²

Substituting

s = ut + 0.5 at²

0 = 60 x t + 0.5 x (-4.5) x t²

2.25t² - 60 t = 0

t² - 26.67 t = 0

t (t-26.67) = 0

t = 0s or t = 26.67 s

So after 26.67 seconds it returns back to the origin

b) We have equation of motion v = u + at

Initial velocity, u = 60 m/s

Acceleration, a = -4.5 m/s²

Time , t = 26.67

Substituting

v = 60 - 4.5 x 26.67 = -60 m/s

Velocity when it returns to the origin = 60 m/s in the -x direction

4 0

4 years ago