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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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Explain why the temperature varies with distance from the Sun in this way?

GenaCL600 [577]

Answer:

The average surface temperature decreases the further you get from the Sun because the more distant planets receive less energy/heat/sunlight per square meter of their surface. This is because the energy from the Sun spreads out (becomes less concentrated) as you travel further from the source/Sun.

Explanation:

6 0

3 years ago

The diagram shows a trace of a wave on a cathode-ray oscilloscope.

QveST [7]

a is the correct answer dear

3 0

3 years ago

A 23.0 kg child plays on a swing having support ropes that are 2.10 m long. A friend pulls her back until the ropes are 45.0 deg

Romashka [77]

Answer:

a. 139.748J

b.3.486m/s

c.zero

Explanation:

a. Given the mass of the child as 23.0kg, rope length is 2.1mand incline is 45°

Potential energy during release is calculated as: $PE=mgh$

#Find vertical difference of when the swing is at rest (2.1m) and when the child is pulled back.

Find the height when the child is pulled back:

$cos 45\textdegree=y/2.10\\\\y=1.48m$

#therefore,vertical difference is 2.1m-1.48m=0.62m

$\therefore PE=mgh\\\ \ =23.0kg\times 9.8m/s^2\times 0.62m\\\ \ =139.748J$

#Hence the potential energy during release is 139.748J

b. From a, above, we have PE=139.748J, M=23.0kg.

At the bottom, all the PE will be transferred into KE. Potential energy is calculated as:

$KE=0.5mv^2\\\\mv^2=2KE\\\\v=\sqrt{2KE/m}\\\\v=\sqrt{2\times 139.748J/23.0}\\\\v=3.486m/s$

#Hence the velocity at the bottom of the swing is 3.486m/s

c. Work is calculated as the product of force by distance.

From a, b above we have mass as 23.0kg .

-since the distance of the ropes remained constant the change in distance is zero:

$W=mgd\\=23.0\times 9.8m/s^2\times 0\\=0$

Therefore the work in the ropes is 0,zero.

8 0

3 years ago

The tendency of all objects to continue with your previous motion when the net force acting on the object is zero is known as?

Bingel [31]

Answer:

Inertia

Explanation:

The state of motion of an object is defined by its velocity the speed with a direction. Thus, inertia could be redefined as follows: Inertia: tendency of an object to resist changes in its velocity - and ( in the absence of an unbalanced force ) will remain with a zero velocity.

4 0

3 years ago

When two capacitors are connected in parallel and then connected to a battery, the total stored energy is 6.7 times greater than

musickatia [10]

Answer:

4.48 and 0.22

Explanation:

Below are the stated formulas for capacitors in series and parallel.

Let both capacitors be C1 and C2 respectively.

For parallel:

Total C = C1 + C2

For series (after rearranging the formular):

Total C = C1C2 / (C1 + C2)

Now, formular to calculate total energy stored is given below.

Parallel:

E = 1/2 * CV^2

= 1/2 * (C1 + C2) * V^2

Series:

E = 1/2 * CV^2

= 1/2 * (C1C2/ (C1 + C2)) * V^2

In the question, it states that energy stored in parallel is 6.7 times the energy when stored in series.

E(parallel) = 6.7E(series)

1/2 * (C1 + C2) * V^2 = 6.7 * 1/2 * (C1C2/ (C1 + C2)) * V^2

(C1 + C2) = 6.7C1C2 / (C1 + C2) (cancelling out V^2 and 1/2 on both sides)

(C1 + C2)^2 = 6.7C1C2

C1^2 + 2C1C2 + C2^2 = 6.7C1C2

C1^2 - 4.7C1C2 + C2^2 = 0

Now,we need to divide through by C2^2 to get an equation of the form ax^2 + bx + c = 0, which we can then solve using the quadratic equation.

C1^2 / C2^2 - 4.7C1 / C2 + 1 = 0

let x = C1 / C2 (x is the ratio of the capacitance of the capacitors)

x^2 - 4 x + 1 = 0

Using the quadratic equation, the solutions are:

x = C1 / C2 = 4.48 and x = C1 / C2 = 0.22 in two decimal places.

8 0

3 years ago