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Nezavi [6.7K]
3 years ago
13

Scientist who first proposed the theory that the continents drifted is __________

Physics
1 answer:
Aloiza [94]3 years ago
4 0

Answer:

Alfred Wegener

Explanation:

Alfred Wegener is a german meteorologist who proposed the theory that the continents drifted, and he presented it to the German Geological Society on January 1912.

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A 3.0 kg rifle is held firmly by a 50.0 kg woman, initially standing still. A 0.06 kg bullet leaves the rifle muzzle with a velo
ohaa [14]

Answer:

48kg

Explanation:

i could be wrong if i am srry

7 0
3 years ago
Calculate the kinetic energy that the earth has because of (a) its rotation about its own axis and (b) its motion around the sun
Dominik [7]

Answer:

a. K_{Axis}=2.574x10^{29}J

b. K_{Orbit}=2.6577x10^{33}J

Explanation:

K_{Axis}=\frac{1}{2}I*w^2

I_{Sphere}=\frac{2}{5}*m*r^2

w=\frac{2\pi }{T} , T=24hrs*\frac{3600s}{1hr} =86400s

radius earth = 6371 km

mass earth = 5,972*10^24 kg

a.

K_{Axis}=\frac{1}{2}*\frac{2}{5}*m*r^2*(\frac{2\pi}{T})^2

K_{axis}=\frac{4\pi^2}{5}*5.98x10^{24}kg*(6.38x10^6m)^2*(\frac{1}{86400s})^2

K_{Axis}=2.574x10^{29}J

b.

T=1year*\frac{365day}{1year}*\frac{24hr}{1day}*\frac{3600s}{1hr}=31536000s

K_{Orbit}=\frac{1}{2}*I*w

I=m*r^2

K_{Orbit}=\frac{1}{2}*m*r^2*(\frac{2\pi}{T})^2

K_{Orbit}=\frac{4\pi^2}{5}*5.98x10^{24}*6.38x10^6m*(\frac{1}{31.536x10^6s})^2

K_{Orbit}=2.6577x10^{33}J

4 0
3 years ago
A Carnot engine has a power output of 150 kW. The engine operates between two reservoirs at 20.0°C and 500°
Nookie1986 [14]
Efficiency η of a Carnot engine is defined to be: 
<span>η = 1 - Tc / Th = (Th - Tc) / Th </span>
<span>where </span>
<span>Tc is the absolute temperature of the cold reservoir, and </span>
<span>Th is the absolute temperature of the hot reservoir. </span>

<span>In this case, given is η=22% and Th - Tc = 75K </span>
<span>Notice that although temperature difference is given in °C it has same numerical value in Kelvins because magnitude of the degree Celsius is exactly equal to that of the Kelvin (the difference between two scales is only in their starting points). </span>

<span>Th = (Th - Tc) / η </span>
<span>Th = 75 / 0.22 = 341 K (rounded to closest number) </span>
<span>Tc = Th - 75 = 266 K </span>

<span>Lower temperature is Tc = 266 K </span>
<span>Higher temperature is Th = 341 K</span>
8 0
3 years ago
Read 2 more answers
In an incline projection the horizontal motion is uniform motion (vx)= constant why?​
svet-max [94.6K]

Answer:

it is constant because there is not any force that oppose the horizontal motion

but the vertical velocity is not constant because there is a gravitational force that oppose the motion .

5 0
2 years ago
Can someone please help me with these physics problems? I just don’t even know where to start.
KIM [24]

#1

for the block of mass 5 kg normal force is given as

F_n = mg

F_n = 5*9.8 = 49 N

friction force is given as

F_f = \mu F_n

F_f = 0.1*49 = 4.9 N

Net force is given as

F_{net} = ma

F_{net} = 5*2 = 10 N

now we know that

F_{net} = F_{app} - F_f

10 = F_{app} - 4.9

F_{app} = 14.9 N

#2

Normal force is given as

F_n = mg

F_n = 6*9.8

F_n = 58.8 N

now we know that

F_{net} = F_{app} - F_f

F_{net} = 0

as object moves with constant velocity

F_{app} = F_f = 15 N

now for coefficient of friction we can use

F_f = \mu F_n

15 = \mu * 58.8

\mu = 0.255

#3

net force upwards is given as

F = 1.2 * 10^{-4} N

mass is given as

m = 7 * 10^{-5} kg

now as per newton's law we can say

F = ma

1.2 * 10^{-4} = 7 * 10^{-5} * a

a = 1.71 m/s^2

#4

As we know that when block is sliding on rough surface

part a)

net force = applied force - frictional force

F_{net} = F_{app} - F_f

ma = F_{app} - F_f

5*6 = 40 - F_{f}

F_f = 40 - 30 = 10 N

part b)

for coefficient of friction we can use

F_f = \mu F_n

10 = \mu * F_n

here normal force is given as

F_n = mg = 5*9.8 = 49 N

now we have

\mu = \frac{10}{49} = 0.204

#5

if an object is initially at rest and moves 20 m in 5 s

so we can use kinematics to find out the acceleration

d = v_i*t + \frac{1}{2}at^2

20 = 0 + \frac{1}{2}a(5^2)

a = 1.6 m/s^2

now net force is given as

F_{net} = ma

F_{net} = 10*1.6 = 16 N

#6

an object travelling with speed 25 m/s comes to stop in 1.5 s

so here acceleration of object is given as

a = \frac{v_f - v_i}{t}

a = \frac{0 - 25}{1.5} = -16.67 m/s^2

now the force is gievn as

F = ma

F = 5*16.67 = 83.3 N

3 0
3 years ago
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