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3 years ago

10

You drive a car 2.0 km to the gas station, 4.0 km to the shopping mall to let your mother off, and 4.5 km back home. The trip ta

kes 20.0 min. What is your average speed?

1 answer:

slamgirl [31]3 years ago

8 0

60 i believe (ssssppppaaaccceeee)

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A rocket, initially at rest on the ground, accelerates straight upward from rest with constant acceleration 58.8m/s2 . The accel

Zanzabum

Split the operation in two parts. Part A) constant acceleration 58.8m/s^2, Part B) free fall.

Part A)
Height reached, y = a*[t^2] / 2 = 58.8 m/s^2 * [7.00 s]^2 / 2 = 1440.6 m

Now you need the final speed to use it as initial speed of the next part.

Vf = Vo + at = 0 + 58.8m/s^2 * 7.00 s = 411.6 m/s

Part B) Free fall

Maximum height, y max ==> Vf = 0

Vf = Vo - gt ==> t = [Vo - Vf]/g = 411.6 m/s / 9.8 m/s^2 = 42 s

ymax = yo + Vo*t - g[t^2] / 2

ymax = 1440.6 m + 411.6m/s * 42 s - 9.8m/s^2 * [42s]^2 /2
ymax = 1440.6 m + 17287.2m - 8643.6m = 10084.2 m

Answer: ymax = 10084.2m

8 0

3 years ago

An object with velocity 141 ft/s has a kinetic energy of 1558.71 ftâˆ™lbf, on a planet whose gravity is 31.5 ft/s2. What is its

Sidana [21]

Answer:

The mass of the object is 5.045 lbm.

Explanation:

Given;

kinetic energy of the object, K.E = 1558.71 ft.lbf

velocity of the object, V = 141 ft/s

The kinetic energy of the object is calculated as;

$K.E = \frac{1}{2} mV^2\\\\mV^2 = 2K.E\\\\m = \frac{2K.E}{V^2} \\\\1 \ lbf = 32.174 \ lbm.ft/s^2\\\\m = \frac{2 \ \times \ 1558.71 \ ft.lbf \ \times \ 32.174 \ lbm.ft/s^2 }{(141 \ ft/s)2 \ \ \times \ \ \ \ 1 \ lbf\ }$

$m = \frac{(2 \ \times \ 1558.71 \ \times \ 32.174) \ lbm.ft^2/s^2 }{(141 )^2\ ft^2/s^2 }\\\\m = \frac{(2 \ \times \ 1558.71 \ \times \ 32.174) \ lbm }{(141 )^2 }\\\\m = 5.045 \ lbm$

Therefore, the mass of the object is 5.045 lbm.

6 0

2 years ago

The atmosphere of Mars is almost all carbon dioxide and the average surface pressure is 610 Pa (as compared with 101,000 Pa on E

Karolina [17]

Answer:

z = 3,737 10⁵ m

Explanation:

a) As they indicate that the atmosphere behaves like an ideal gas, we can use the equation

P V = n R T

P = (n r / V) T

We replace

P = (n R / V) T₀ $e^{- C z}$

b) Let's apply this equation in the points

Lower

.z = 0

P₀ = 610 Pa

P₀ = (nR / V) T₀

Higher.

P = 10 Pa

P = (n R / V) T₀ e^{- C z}

We replace

P = P₀ e^{- C z}

e^{- C z} = P / P₀

C z = ln P₀ / P

z = 1 / C ln P₀ / P

Let's calculate

z = 1 / 1.1 10⁻⁵ ln (610/10)

z = 3,737 10⁵ m

4 0

3 years ago

An astronaut who is repairing the outside of her spaceship accidentally pushes away a 92.9 cm long steel rod, which flies off at

DiKsa [7]

Answer:

V = 0.0723 volts = 72.3 milivolts

Explanation:

The emf induced in the rod is the motional emf due to the magnetic field. This motional emf can be calculated by the following formula:

$EMF = V = vBl Sin\theta$

where,

V = Motional EMF = ?

v = speed of rod = 12.5 m/s

B = Magnetic Field = 6.23 mT = 0.00623 T

l = Length of rod = 92.9 cm = 0.929 m

θ = angle between v and B = 90°

Therefore,

$V = (12.5\ m/s)(0.00623\ T)(0.929\ m)Sin\ 90^o\\$

<u>V = 0.0723 volts = 72.3 milivolts</u>

7 0

2 years ago

Which describes the changes in visible light moving from red to violet?

eimsori [14]

The wavelength decreases to roughly half.
(The frequency roughly doubles.)

3 0

3 years ago