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3 years ago

14

An object moving north with an initial velocity of 14 m/s accelerates 5 m/s2 for 20 seconds. What is the final velocity of the o

bject?
39 m/s
90 m/s
114 m/s
414 m/s

2 answers:

ruslelena [56]3 years ago

6 0

Here is the answer ! Hope it helps.

lisabon 2012 [21]3 years ago

5 0

Answer:

option C

Explanation:

Final velocity of the object is 114 m / s. Hence, final velocity of the object is 114 m / s.

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Consider a 2-kg bowling ball sits on top of a building that is 40 meters tall. It falls to the ground. Think about the amounts o

likoan [24]

Answer:

1) At the highest point of the building.

2) The same amount of energy.

3) The kinetic energy is the greatest.

4) Potential energy = 784.8[J]

5) True

Explanation:

Question 1

The moment when it has more potential energy is when the ball is at the highest point in the building, that is when the ball is at a height of 40 meters from the ground. It is taken as a point of reference of potential energy, the level of the soil, at this point of reference the potential energy is zero.

$E_{p} = m*g*h\\E_{p} = 2*9.81*40\\E_{p} = 784.8[J]$

Question 2)

The potential energy as the ball falls becomes kinetic energy, in order to be able to check this question we can calculate both energies with the input data.

$E_{p}=m*g*h\\ E_{p} = 2*9.81*20\\ E_{p} = 392.4[J]\\$

And the kinetic energy will be:

$E_{k}=0.5*m*v^{2}\\ where:\\v = velocity = 19.8[m/s]\\E_{k}=0.5*2*(19.8)^{2}\\ E_{k}=392.04[J]$

Therefore it is the ball has the same potential energy and kinetic energy as it is half way through its fall.

Question 3)

As the ball drops all potential energy is transformed into kinetic energy, therefore being close to the ground, the ball will have its maximum kinetic energy.

$E_{k}=E_{p}=m*g*h = 2*9.81*40\\ E_{k} = 784.8[J]\\ E_{k} = 0.5*2*(28)^{2}\\ E_{k} = 784 [J]$

Question 4)

It can be easily calculated using the following equation

$E_{p} =m*g*h\\E_{p}=2*9.81*40\\E_{p} =784.8[J]$

Question 5)

True

The potential energy at 20[m] is:

$E_{p}=2*9.81*20\\ E_{p}= 392.4[J]\\The kinetic energy is:\\E_{k}=0.5*2*(19.8)^{2} \\E_{k}=392[J]$

3 0

3 years ago

During normal beating, the heart creates a maximum 4.00-mV potential across 0.300 m of a person’s chest, creating a 1.00-Hz elec

erik [133]

Answer:

(a). The maximum electric field strength is 0.0133 V/m.

(b). The maximum magnetic field strength in the electromagnetic wave is $4.433\times10^{-11}\ T$

(c). The wavelength of the electromagnetic wave is $3\times10^{8}\ m$

Explanation:

Given that,

Maximum potential = 4.00 mV

Distance = 0.300\ m

Frequency = 1.00 Hz

(a). We need to calculate the maximum electric field strength

Using formula of the potential difference

$\Delta V=Ed$

$E=\dfrac{\Delta V}{d}$

$E=\dfrac{4.00\times10^{-3}}{0.300}$

$E=0.0133\ V/m$

(b). We need to calculate the maximum magnetic field strength in the electromagnetic wave

Using formula of the maximum magnetic field strength in the electromagnetic wave

$B=\dfrac{E}{c}$

Put the value into the formula

$B=\dfrac{0.0133}{3\times10^{8}}$

$B=4.433\times10^{-11}\ T$

(c). We need to calculate the wavelength of the electromagnetic wave

Using formula of wavelength

$c=f\lambda$

$\lambda=\dfrac{c}{f}$

Put the value into the formula

$\lambda=\dfrac{3\times10^{8}}{1.00}$

$\lambda=3\times10^{8}\ m$

Hence, (a). The maximum electric field strength is 0.0133 V/m.

(b). The maximum magnetic field strength in the electromagnetic wave is $4.433\times10^{-11}\ T$

(c). The wavelength of the electromagnetic wave is $3\times10^{8}\ m$

4 0

3 years ago

Which two of the following reduce the background noise in magneto- medicine?

horrorfan [7]

Answer:

The answer is b.) and d.)

Explanation:

The options to reduce the background noise in magneto-medicine are given as follows:

a.) Orienting the heart parallel to the Earth's field

- This will have no significant effect on the measurements.

b.) Taking the difference of two nearby sensor measurements (gradiometer).

-This answer is TRUE.

c.) Placing the heart in a perpendicular fashion to the Earth's magnetic field.

_ This answer also will not have any significant effect on measurements.

d.) Using physical means to shield environmental fields.

- This answer is TRUE.

4 0

3 years ago

A donkey is attached by a rope to a wooden cart at an angle of 23° to the horizontal. the tension in the rope is 210 n. if the c

kaheart [24]

Answer:

787528.7 J

Explanation:

Work done: This can be defined as the product of force and distance along the direction of force. The S.I unit of work is Joules (J).

From the question,

W = Tcos∅(d)............. Equation 1

Where W = work done, T = tension in the rope, ∅ = the angle of the rope to the horizontal, d = distance.

But,

d = v(t)..................... equation 2

Where v = velocity, t = time

Substitute equation 2 into equation 1

W = Tcos∅(vt)............. Equation 3

Given: T = 210 N, ∅ = 23°, v = 7 km/h = 1.94 m/s, t = 35 min = 2100 s

Substitute into equation 3

W = 210(cos23°)(1.94×2100)

W = 787528.7 J

8 0

3 years ago

Age, height, and weight are examples of numerical data.

Andrej [43]

Answer:

True

Explanation:

Examples of numerical data are height, weight, age

7 0

2 years ago

Read 2 more answers