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3 years ago

Answer needed asap............

Physics

2 answers:

NikAS [45]3 years ago

5 0

I): Speed=Distance/Time
=65-30 km/12:30-12:00 hrs
=35 km/00:30hrs
=3500 m/1800 s
=1.94m/s

ii): Average Speed=Total Distance/Total Time
=100000 m/7200 s
=13.88 m/s

iii):No because it has different speeds at
different time intervals

photoshop1234 [79]3 years ago

5 0

i). 70 km/hr ii). 50 km/hr III). No. Some half hours are slower and others are faster. Uniform motion means speed never changes. Like from 11.30 to 12.00 it doesn't even move at all

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In triangle ABC, the angles A and B have the same measure, while the measure of angle C is 21degrees larger than the measure o

Lynna [10]

180 = 2x+x+21
159 = 3x
x = 53
Angle A = 53°
Angle B = 53°
Angle C = 53+21 = 74°

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3 years ago

Identify the object or objects in motion in each example of kinetic energy.

Leto [7]

Answer:

A speedy train

Explanation:

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3 years ago

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A satellite is orbiting the earth just above its surface. The centripetal force making the satellite follow a circular trajector

Pavlova-9 [17]

Answer:

$v=7905m/s$

$t=5063s$

Explanation:

A satellite is orbiting the earth just above its surface. The centripetal force making the satellite follow a circular trajectory is just its weight, so its centripetal acceleration is about 9.81 m/s2 (the acceleration due to gravity near the earth's surface). If the earth's radius is about 6370 km, how fast must the satellite be moving? How long will it take for the satellite to complete one trip around the earth?

The weight of the satellite is the centripetal force, so:

$W=mg=F_{cp}=ma_{cp}=m\frac{v^2}{r}$

Which means: $g=\frac{v^2}{r}$

We can calculate then the velocity:

$v=\sqrt{gr}=\sqrt{(9.81m/s^2)(6370000m)}=7905m/s$

For calculating how long will it take for the satellite to complete one trip around Earth we consider that the distance of the trip is the circumference of the orbit. This is calculated as $C=2\pi r$ .

Since velocity is v=d/t, we have:

$t=d/v=C/v=2\pi r/v=\frac{2\pi 6370000}{7905m/s} =5063s$

5 0

3 years ago

A parallel-plate capacitor has square plates that are 7.20 cm on each side and 3.40 mm apart. The space between the plates is co

Lilit [14]

Answer:

U = 218 nJ

Explanation:

We are given;

Spacing between the plates; d = 3.4 mm = 3.4 × 10^(-3) m

Voltage across the capacitor; V = 96 V

Dimension of the square plates is 7.2cm x 7.2cm.

So, Area = 7.2 × 7.2 = 51.84 cm² = 51.84 × 10^(-4) m²

Permittivity of free space; ε_o = 8.85 × 10^(-12) C²/N.m²

From relative permeability table;

Dielectric constant of Pyrex; k1 = 5.6

Dielectric constant of polystyrene; k2 = 2.56

Now, formula for capacitance of a capacitor with Dielectric is;

C = kC_o

Where, C_o = ε_o(A/d)

Since there are 2 capacitors, d will now be d/2 = (3.4 × 10^(-3))/2 m = 1.7 × 10^(-3)

Since we have 2 capacitor, thus ;

C1 = k1*ε_o*(A/d)

C1 = (5.6 × 8.85 × 10^(-12) × (51.84 × 10^(-4))/(1.7 × 10^(-3))

C1 = 1.51 × 10^(-10) F

Similarly;

C2 = (2.56 × 8.85 × 10^(-12) × (51.84 × 10^(-4))/(1.7 × 10^(-3))

C2 = 0.691 × 10^(-10) F

For capacitors in series, formula for total capacitance(Cs) is;

1/Cs = (1/C1) + (1/C2)

Simplifying this, we have;

Cs = (C1*C2)/(C1 + C2)

Plugging in the relevant values ;

Cs = (1.51 × 10^(-10)*0.691 × 10^(-10))/((1.51 × 10^(-10)) + (0.691 × 10^(-10)))

Cs = 0.474 × 10^(-10) F

The formula for energy stored in a capacitor with 2 Dielectrics is given as;

U = ½Cs*V²

So,

U = ½ × 0.474 × 10^(-10) × 96²

U = 2.18 × 10^(-7) J = 218 × 10^(-9) = 218 nJ

8 0

3 years ago

The weight of a girl with the mass of 40.0kg is ?

Allushta [10]

Answer:

392 Newtons

Explanation:

In order to find the weight, you have to multiply the mass by the gravitation constant (9.8), which gives us 40.0 * 9.8 = 392 Newtons.

4 0

3 years ago