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finlep [7]
4 years ago
14

What is a common ancestor

Physics
1 answer:
RSB [31]4 years ago
8 0

Answer:

Common descent describes how, in evolutionary biology, a group of organisms share a most recent common ancestor. There is massive evidence of common descent of all life on Earth from the last universal common ancestor

Explanation:

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A meter rule balance on a knife headge at the 55cm mark wheb a mass of 40g from 995cm .find the mass of the meter rule.
umka2103 [35]

Answer:

Let the weight of the ruler be X.

Now X acts in the middle, so we have 55-50 = 50cm

Since left hand movement= right hand movement

X(55-50)=90(95-55)

5X= 90×40

X=320cm

Hence the weight of the ruler is 320g

Explanation:

7 0
3 years ago
A skier descends a mountain at an angle of 35.0º to the horizontal. If the mountain is 235 m long, what are the horizontal and v
kumpel [21]
Opposite from the angle is 134.7905

Adjacent to the angle is 192.5007
6 0
4 years ago
Read 2 more answers
A high-jumper, having just cleared the bar, lands on an air mattress and comes to rest. Had she landed directly on the hard grou
Hoochie [10]

Answer:

e. the air mattress exerts the same impulse, but a smaller net avg force, on the high-jumper than hard-ground.

Explanation:

This is according to the Newton's second law and energy conservation that the force exerted by the hard-ground is more than the force exerted by the mattress.

The hard ground stops the moving mass by its sudden reaction in the opposite direction of impact force whereas the mattress takes a longer time to stop the motion of same mass in a longer time leading to lesser average reaction force.

<u>Mathematical expression for the Newton's second law of motion is given as:</u>

F=\frac{dp}{dt} ............................................(1)

where:

dp = change in momentum

dt = time taken to change the momentum

We know, momentum:

p=m.v

Now, equation (1) becomes:

F=\frac{d(m.v)}{dt}

<em>∵mass is constant at speeds v << c (speed of light)</em>

\therefore F=m.\frac{dv}{dt}

and, \frac{dv}{dt} =a

where: a = acceleration

\Rightarrow F=m.a

also

F\propto \frac{1}{dt}

so, more the time, lesser the force.

<em>& </em><u><em>Impulse:</em></u>

I=F.dt

I=m.a.dt

I=m.\frac{dv}{dt}.dt

I=m.dv=dp

∵Initial velocity and final velocity(=0), of a certain mass is same irrespective of the stopping method.

So, the impulse in both the cases will be same.

4 0
3 years ago
A bicycle tire is spinning counterclockwise at 2.70 rad/s. During a time period At 1.90 s, the tire is stopped and spun in the o
Naddik [55]

Answer:

a) -5.40 rad/s

b) -2.842 rad/s²

Explanation:

The direction is important in dealing with such questions. Clockwise is considered negative and counterclockwise is considered positive

a) Δω = final angular velocity - initial angular velocity

          = -2.70 rad/s - 2.70 rad/s

          = -5.40 rad/s

b) ∝ = Δω/Δt = (-5.40 rad/s)/1.90s = -2.842 rad/s²

7 0
4 years ago
What do we call a change in the car’s speed or direction?<br><br><br> Help!!
zhuklara [117]
The answer for this question is acceleration
8 0
4 years ago
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