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wolverine [178]

4 years ago

6

Kim sees a dog jump onto the road. Her response time before she hits the brakes is 0.3 seconds. How far will her car travel duri

ng her response time if she is moving at 20 m/s?

1 answer:

Harlamova29_29 [7]4 years ago

4 0

Answer:

6 seconds i think

Explanation:

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A satellite is in elliptical orbit with a period of 7.20 104 s about a planet of mass 7.00 1024 kg. At aphelion, at radius 5.1 1

soldi70 [24.7K]

Answer:

1.64x $10^{-4}$ rad/s

Explanation:

Given:

satellite is in elliptical orbit with a period T= 7.20 x $10^{4}$ s

Mass of planet m= 7.00x $10^{24}$ kg

Satellite's angular speed ωa- = 4.987 10-5 rad/s

At aphelion, at radius Ra= 5.1 x 10^7 m

Assuming torque is zero for this system, therefore, the conservation of angular momentum can be defines as

Lp = La

Ip ωp = Ia ωa--->eq(1)

Where,

'a' represents aphelion and 'p' represents perihelion

ω represents angular velocity

and I represents the rotational inertia

Since, I= 1/2 mR²

Here R is the radius at aphelion / perihelion

m = mass of planet

eq(1)=> ωp= Ia ωa/ Ip

ωp= (1/2 m Ra² ωa) / 1/2 m Rp²

ωp= (Ra/Rp)² ωa --->eq(2)

In order to find Rp, we use : 2a= Rp + Ra

where a represents semimajor axis

with the help of Kepler's third law for elliptical orbits

a= ∛(GmT²/4π²)

a= ∛ 6.67x $10^{-11}$ x 7.00x $10^{24}$ x (7.20 x $10^{4}$ )² / 4π²

a= 3.97 x $10^{7}$ m

2a= Rp + Ra

Rp= 2a-Ra

Rp= 2 x 3.97 x $10^{7}$ - 5.1x $10^{7}$

Rp= 2.84 x $10^{7}$ m

Substituting all the required values in eq 2, we have

ωp= (Ra/Rp)² ωa

ωp= (5.1x $10^{7}$ /2.84 x $10^{7}$ )² x 4.987 x $10^{-5$

ωp= 3.224 x 4.987 x $10^{-5$

ωp= 1.64x $10^{-4}$ rad/s

Therefore, angular speed at perihelion is 1.64x $10^{-4}$ rad/s

3 0

3 years ago

If y(t)y(t) describes the position with time, what is the proper formula for velocity with time? (Recall velocity is related to

PilotLPTM [1.2K]

Answer:

Although this question is not complete, I would give a general solution to this kind of problems.

If y(t) describes the position of a body with time such that

y(t) = at^(n) + bt^(m) + C

Then

V(t) = dy(t)/dt = ant^(n-1) + bmt^(m-1)

Explanation:

As an example supplies the position of a particle is given by

y(t) = 4t³- 3t² + 9

V(t) = 4x3t²- 3x2t¹

V(t) = d(t)/dt = 12t² - 6t.

Another example,

If y(t) = 15t³ - 2t² + 30t -80

V(t) = d(t)/dt = 15x3t² - 4t +30 = 45t² + 4t + 30.

Basically, in the equations above the powers of t reduces by one when computing the velocity function from y(t) by differentiation (calculating the derivative of y(t)). The constant term C (9 and 80 in the functions of y(t) in examples 1and 2 above) reduces to zero because the derivative of a constant (and ordinary number without the t attached to it) is always zero.

One last example,

y(t) = 2t^6 -3t²

V(t) = d(t)/dt = 12t^5 - 6t

6 0

4 years ago

Identification of elements compounds and mixtures from a given table

Firdavs [7]

Answer:

the elements are made up of only one kind of atom, the compounds consist of two or more elements that are chemically combined, and the mixtures are physical combination of two or more substances

3 0

3 years ago

A measurement standard is defined as ____.

Serggg [28]

<u>Answer:</u>

A measurement standard is defined as 'the exact quantity people agree to use for comparison'.

<u>Explanation:</u>

For the same type of quantity, there is a unit of measurement which is defined and adopted either conventionally or by law which is used as standard for measurement of that quantity.

This measurement standard is defined as 'the exact quantity people agree to use for comparison'.

For example, for length the standard unit of measurement is 'meter'.

5 0

4 years ago

Read 2 more answers

A coil 3.85 cm radius, containing 450 turns, is placed in a uniform magnetic field that varies with time according to B=( 1.20×1

Nimfa-mama [501]

Answer:

0.025V + (0.000218V/s³) t³

Explanation:

Parameters given:

Radius of coil, r = 3.85 cm = 0.0385 m

Number of turns, N = 450

Magnetic field, B = ( 1.20×10^(−2) T/s )t + (2.60×10^(−5) T/s4 )t^4.

The magnitude of Induced EMF is given as:

E = N * A * dB/dt

Where A is the area of the coil

First, we differentiate the magnetic field with respect to time:

dB/dt = 0.012 + 0.000104t³

Therefore, EMF will be:

E = 450 * 3.142 * (0.012 + 0.000104t³)

E = 2.096(0.012 + 0.000104t³)

E = 0.025V + (0.000218V/s³)t³

6 0

3 years ago

Read 2 more answers