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Jlenok [28]
3 years ago
8

An egg is dropped from a building that is 61 m high.

Physics
1 answer:
Allisa [31]3 years ago
3 0

Answer:

Initial Velocity = 0 m/s

Final Velocity = 34.6 m/s

time = 3.5 s

Explanation:

The initial velocity must be zero since, the egg must be at rest initially, before dropping.

<u>Initial Velocity = 0 m/s</u>

Now, for time we use 2nd equation of motion:

h = Vi t + (1/2)gt²

where,

h = Height = 61 m

Vi = Initial Velocity = 0 m/s

g = 9.8 m/s²

t =time = ?

Therefore,

61 m = (0 m/s)(t) + (1/2)(9.8 m/s²)t²

t² = (61 m)(2)/(9.8 m/s²)

t = √(12.45 s²)

<u>t = 3.5 s</u>

Now, for final velocity we will use 1st equation of motion:

Vf = Vi + gt

Vf = 0 m/s + (9.8 m/s²)(3.5 s)

Vf = 34.6 m/s

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What is the velocity of an object with a kinetic energy of 800 J and a mass of 12 kg?
Elis [28]

K.E = 1/2 mv²

800 = 1/2 ×12 ×v²

800 =  6 v²

800 / 6  =  v²

=   133.4    =v²

√133.4  =   √v²

11.5   =  v²

I hope this answer is correct.

3 0
3 years ago
A carpenter is driving a 15.0-g steel nail into a board. His 1.00-kg hammer is moving at 8.50 m/s when it strikes the nail. Half
bekas [8.4K]

Answer: The increase in temperature of the nail after the three blows is 8.0636 Kelvins. The correct option is (d).

Explanation:

Kinetic energy of the hammer ,K.E.=

\frac{1}{2}mv^2=\frac{1}{2}1.00 kg\times (8.50 m/s)^2=36.125 J

Half of the kinetic energy of the hammer is transformed into heat in the nail.

Energy transferred to the nail in one blow =

\frac{1}{2}K.E.=\frac{1}{2}\times 36.125 J=18.0625 J

Total energy transferred after 3 blows,Q =3\times 18.0625 J=54.1875 J

Mass of the nail = 15 g = 0.015 kg

Change in temperature =\Delta T

Specif heat of the steel = c = 448 J/kg K

Q=mc\Delta T

54.1875 J=0.015 kg\times 448 J/kg K\times \Delta T

\Delta T=8.0636 K\approx 8.1 K

The increase in temperature of the nail after the three blows is 8.1  Kelvins.Hence, correct option is (d).

4 0
3 years ago
Which best explains why changes to the atomic theory were necessary?. A] differing ideas. .B] experimental evidence. . C] better
Goshia [24]
Hello!

The best explanation is the new "experimental evidence", which occur with the help of new and improved technology. For this question, I suggest you to answer letter b).

Hugs!


7 0
3 years ago
Read 2 more answers
4. A car accelerates, from rest, at 2.4 m/s?. How fast is the car traveling
pantera1 [17]

Answer:

19.2m/s

Explanation:

Assuming that 2.4m/s^2 was the acceleration and not a typo, we can use the equation v=at, where v=velocity, a=acceleration, and t=time,

plug in known varibles,

v=2.4*8

v=19.2m/s

4 0
3 years ago
A car accelerates from 20mi/hr to 60mi/hr. How many times greater is the car's kinetic energy at the higher speed compared to th
Ainat [17]

Answer:

9 times

Explanation:

Kinetic energy is:

KE = ½ mv²

When we triple the velocity, the kinetic energy increases by a factor of 9.

9KE = ½ m(3v)²

4 0
3 years ago
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