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3 years ago

What is a scientific theory

Physics

1 answer:

Tomtit [17]3 years ago

3 0

Answer:

They arn't usually guesses, but they are well made theorys or explanations. Its a well-substantiated explanation of facts that have been confirmed in expirements.

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What kind of line on a distance vs. time graph indicates that the object is accelerating?

suter [353]

Answer: a curved line

Explanation: a straight line indicates that the object is moving at a constant velocity because it has one slope, but a curved line on a distance-time graph indicates that the velocity is constantly changing because the slope is changing, which is acceleration. the line could be curved in any direction, as long as it shows a change in slope.

7 0

3 years ago

Camping equipment weighting 5000N is pulled across a frozen lake by means of a horizontal rope. There is a frictional force of 3

Dmitry [639]

Answer:

The work done by the campers is $4\times10^{5}\ J$

(b) is correct option.

Explanation:

Given that,

Weight = 5000 N

Frictional force = 300 n

Distance = 1000 m

Constant rate of speed = 0.20 m/s²

We need to calculate the force

Using newton's law of motion

$F-F_{\mu}=ma$

$F-300=\dfrac{5000}{10}\times0.20$

$F=\dfrac{5000}{10}\times0.20+300$

$F=400\ N$

We need to calculate the work done

Using formula of work done

$W=F\times d$

Put the value into the formula

$W=400\times1000$

$W=4\times10^{5}\ J$

Hence, The work done by the campers is $4\times10^{5}\ J$

3 0

4 years ago

A simple Atwood’s machine uses a massless

Lady bird [3.3K]

The Atwood's machine is in motion starting from rest, then Vf = Vo + a(t).
Final Velocity is given as 6.7 m/s and the time is 1.9 s thus 6.7= 0+ a(1.9) 
then a = 6.7/1.9 = 3.526 m/s². 
The Atwood's Machine also has the formula d= distance = 1/2a(t²) 
distance given is 6.365 m , then 6.365 = 1/2 a (1.9)², 
a = 3.526 m/s² the same acceleration. 
a= g(m1-m2) / m1+m2) 
m1a + m2a = m1g - m2g 
m1a - m1g = -m2g - m2a 
3.526 m1 - 9.81 m1 = -9.81m2 - 3.526 m2 
-6.28 m1 = -13.34 m2 
0.47 m1= m2 
if 24J = 1/2mv² 
then 24J = 1/2 m1 ( 6.7)² 
48/ 44.89 = m1 
1.069 kg = m1 , then 
0.47(1.069) = m2 
0.503 kg = m2

6 0

4 years ago

A 0.030 kg lead bullet hits a steel plate, both initially at 20?C. The bullet melts and splatters on impact. Assume that 80% of

Dmitry_Shevchenko [17]

Answer:

(a). The required is 1871.2 J.

(b). The speed the lead bullet is 395 m/s.

(c). The 20% of energy must have gone into collision between steel plate and bullet.

Explanation:

Given that,

Mass of bullet = 0.030 kg

Temperature = 20°C

(a). We need to heat required to increase the temperature of the lead bullet and melt it

Using formula of heat

$Q=mS\Delta T+mL$

Where, m = mass of lead bullet

S = specific heat

L = latent heat

T = Temperature

Put the value into the formula

$Q=0.030\times130\times(327.5-20)+0.030\times22400$

$Q=1871.2\ J$

The required is 1871.2 J.

(b). Assume that 80% of the bullet’s kinetic energy goes into increasing its temperature and then melting it

We need to calculate the energy

$Q=\dfrac{1871.2}{0.8}$

$Q=2339 J$

We need to calculate the speed the lead bullet

Using formula of speed

$K.E=Q$

$\dfrac{1}{2}mv^2=2339$

$v^2=\dfrac{2339\times2}{0.030}$

$v=\sqrt{\dfrac{2339\times2}{0.030}}$

$v=394.8 = 395\ m/s$

The speed the lead bullet is 395 m/s.

(c). The 20% of energy must have gone into collision between steel plate and bullet.

Hence, This is the required solution.

6 0

3 years ago

Student C said, “I don’t agree with either model you drew. I think the Sun goes around Earth. The evidence is that you can see t

xxTIMURxx [149]

Answer:

See the explanation below

Explanation:

Student c's belief is fulfilled only for the movement of the earth with respect to the sun. But it has no validity or does not exist when it is necessary to explain other physical phenomena with respect to other satellites. For example, how would you explain the phases of the moon, if the Earth is located in the center of the Galaxy?, another serious question regarding the observations made by scientists millions of years ago, where they observed that the distances of the Earth from other planets were changing, with respect to time. If the Earth was in the center, all the planets and the sun would revolve around it preserving a constant distance (radius), at all times.

Other phenomena to explain would be the seasons on Earth, these are due to the axis of inclination of the Earth and the rotation of it around the sun.

5 0

3 years ago