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Sunny_sXe [5.5K]
3 years ago
14

If a 4.5 kg object is dropped from a height of 6.0 m, what will be its velocity when it is halfway toward the ground? (Use g = 9

.80 m/s2, and ignore air resistance.) 7.7 m/s 11 m/s 16 m/s 29 m/s
Physics
2 answers:
dangina [55]3 years ago
7 0
When an object falls or is dropped from rest it's initial velocity is zero.
Using the equations for a motion in straight line. I can find the time it takes to reach 3.0 m down (half way).
x = vt - 4.9t²
-3 = 0 - 4.9t²
-3/-4.9 = t²
0.6122 = t²
0.7825 sec = t

v = v - gt
v = 0 - 9.8(0.7825)
v = -7.67 m/s
the negative denotes downward direction.

You  could also solve the problem using potential and kinetic energy.

Since it starts with maximum PE and gets converted to KE when it hits the ground. mgh = mv²/2
mass cancels, use 3 meters for the halfway distance
-9.8(-3) = v²/2
29.4 * 2 = v²
√(58.8) = 7.67 m/s downwards
notsponge [240]3 years ago
6 0

Answer:

7.7 rounded

Explanation:

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The force pressing two stacked objects together is equal to the weight of the object on top. The friction between a piece of woo
34kurt

Answer: B. Concrete

Explanation:

Let N = reacting force pressing the bodies in context together (units in Newtons),

The question stated that the force pressing the two mounted/stacked objects together is equal to the weight of the object on top.

We need to start by finding the weight of the piece of wood.

friction is given by

f = μN

The value of f is 22.5,

and from the chart reference the coefficient of friction between wood and stone, μ is 0.30.

22.5 = 75. 0.30

Putting the values into the equation: 22.5 = 0.30N.

Divide both sides by 0.30 to find the value of N:

N= 22.5/0.3 = 75

Now that the piece of wood will be placed on another surface, its weight of 75 Newton is the force pressing the two bodies together.

To determine the new surface, you should find the new coefficient of friction by using the new value of the force of friction given 46.5:

46.5 = µ(75).

Divide both sides by 75 to isolate μ.

The refer chart also indicates that the coefficient of friction equals 0.62 between wood and concrete, so the new surface corresponding to 0.62 is the concrete, which is (B).

3 0
4 years ago
How much electrical energy is used by the river cooker oven rated 800 W ,230 V is switched on for 30 minutes
mariarad [96]

Answer:

E = 1440 kJ

Explanation:

It is given that,

Power of a cooker oven is 800 W

Voltage at which it is operated is 230 V

Time, t = 30 minutes = 1800 seconds

We need to find the electrical energy used by the cooker oven. The product of power and time is equal to the energy consumed. So,

E=P\times t\\\\E=800\ W\times 1800\ s\\\\E=1440000\ J\\\\\text{or}\\\\E=1440\ kJ

So, electrical energy of 1440 kJ is consumed by the cooker oven.

8 0
3 years ago
Which type of mirror would you use to cook a hot dog and why?
alexandr1967 [171]
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Astronauts need special tools to work in space. One specially designed tool that astronauts use is a screwdriver. Using Newton’s
Softa [21]
Due to the fact that for every action there is an equal reaction for every turn on the screw the screw will exert energy equal to the amount you gave
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3 years ago
The blackbody radation emmitted from a furnace peaks at a wavelength of 1.9 x 10^-6 m (0.0000019 m). what is the temperature ins
krek1111 [17]

Answer:

Temperature, T = 1542.10 K

Explanation:

It is given that,

The black body radiation emitted from a furnace peaks at a wavelength of, \lambda=1.9\times 10^{-6}\ m

We need to find the temperature inside the furnace. The relationship between the temperature and the wavelength is given by Wein's law i.e.

\lambda\propto \dfrac{1}{T}

or

\lambda=\dfrac{b}{T}

b = Wein's displacement constant

\lambda=\dfrac{2.93\times 10^{-3}}{T}

T=\dfrac{2.93\times 10^{-3}}{\lambda}

T=\dfrac{2.93\times 10^{-3}}{1.9\times 10^{-6}\ m}

T = 1542.10 K

So, the temperature inside the furnace is 1542.10 K. Hence, this is the required solution.

3 0
3 years ago
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