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4 years ago

Define colloid and list two examples.

1 answer:

8 0

<span>Colloid, in chemistry definition is a heterogenous mixture, of one substance is different from another, when mixed, either of the substance (particularly the solid one), is evenly mixed with each other. It could clearly be seen when one mixes a solution in a suspension state because it forms a cloudy solution, however, in like suspension, it does not settle at the bottom of the mixture. Best example of this is milk. When you mix milk powder to a hot water, the solution is mixed evenly however the color of the water from transparent changes to milkish white.</span>

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A 10N falling encounters 10N of air resistance (upward force). The net force on the object is:

NemiM [27]

0 N. It's being pushed up the same amount it's being pushed down, so it cancels out.

6 0

3 years ago

How do you find the speed of an electromagnetic wave? Multiply the wavelength by the frequency. Dvide the frequency by the wavel

Leokris [45]

Answer:

Multiply the wavelength by the frequency.

Explanation:

The velocity of a wave is the frequency times the wavelength.

8 0

3 years ago

A ball with mass of 0.050 kg is dropped from a height of h1 = 1 .5 m. It collides with the floor, then bounces up to a height of

Iteru [2.4K]

Answer:

Explanation:

Impulse of reaction force of floor = change in momentum

Velocity of impact = √ 2gh₁

= √ 2 x 9.8 x 1.5 = 5.4 m /s.

velocity of rebound = √2gh₂

= √ 2x 9.8 x 1

= 4.427 m / s.

Initial momentum = .050 x 5.4 = .27 kg m/s

Final momentum = .05 x 4.427 = .22 kg.m/s

change in momentum = .27 - .22 = .05 kg m/s

Impulse = .05 kg m /s

Impulse = force x time

force = impulse / time

.05 / .015 = 3.33 N.

kinetic energy = 1/2 m v²

Initial kinetic energy = 1/2 x .05 x 5.4²

= 0.729 J

Final Kinetic Energy =1/2 x .05 x 4.427²

= 0.489 J

Change in Kinetic energy =0 .24 J

Lost kinetic energy is due to conversion of energy into sound light etc.

4 0

4 years ago

Mary spots Bill approaching the dorm at a constant rate of 2.00 m/s on the walkway that passes directly beneath Mary's window, 1

vagabundo [1.1K]

Answer:

Mary will have to wait for 63.2 seconds

Explanation:

Time required for the apple to drop from a height of 17.0 m above the ground to 1.65 m above the ground is given by the formula below:

t = √2h/g where h is height through which the object falls, g is acceleration due to gravity

h = 17.0 - 1.65 = 15.35 m

g = 9.8 m/s²

t = √(2 * 15.35/9.8)

t = 1.77 s or approximately 1.8 s

Time taken for bill to get to the point below Mary's window is given below;

time taken = distance/velocity

distance = 130 m; velocity = 2.0 m/s

time taken by Bill = 130/2.0 = 65 s

Therefore, Mary will have to wait for (65 - 1.8) s = 63.2 seconds

4 0

3 years ago

The 1.5-kg collar C starts from rest at A and slides with negligible friction on the fixed rod in the vertical plane. Determine

arlik [135]

Answer:

Explanation:

check attached image for figure, there is supposed to be a figure for this question containing a distance(height of collar at position A) but i will assume 0.2m or 200mm

Consider the energy equilibrium of the system

$U_{A-B}=\bigtriangleup T\\\\F\cos 30°\times h_A - F\sin30°\times h_A + Wh_A=\frac{1}{2}m(v^2_B-v^2_A)\\\\v_B=\sqrt{\frac{2Fh_A(\cos 30° - \sin30°)+mgh_A}{m+v^2_A}}$

Here, F is the force acting on the collar, $h_A$ is the height of the collar at position A, m is the mass of the collar C, g is the acceleration due to gravity, $v_B$ is the velocity of the collar at position B, and $v_A$ is the velocity of the collar at A

Substitute 14.4N for F, 0.2m for $h_A$ , 1.5kg for m, $9.81m/s^2$ for g and 0 for $v_A$

$v_B=\sqrt{\frac{2(14.4\times 0.2(\cos 30° - \sin30°)+1.5\times 9.81\times 0.2}{1.5+0}}\\\\=\sqrt{\frac{6.618}{1.5}}\\\\=4.412m/s$

Therefore, the velocity at which the collar strikes the end B is 4.412m/s

8 0

3 years ago