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4 years ago

During which period did the first large herbivores and carnivores appear?

1 answer:

7 0

The first large herbivores and carnivores appeared during the Mesozoic Era, which is divided into three periods-- Triassic, Jurassic and Cretaceous. The herbivores and and carnivores increased in size during the Jurassic Period. And some of the largest dinosaurs emerged during this period as well.

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A 250 g air-track glider is attached to a spring with springconstant 4.0 N/m. Th damping constant due to air resistance is0.015

vaieri [72.5K]

Answer:

33.33 seconds

Explanation:

$N=\dfrac{1}{e}N_0$

$N_0$ = Initial length pulled = 20 cm

b = Damping constant = 0.015 kg/s

k = Spring constant = 4 N/m

m = Mass of glider = 250 g

Time period is given by

$T=2\pi\sqrt{\dfrac{m}{k}}\\\Rightarrow T=2\pi\sqrt{\dfrac{0.25}{4}}\\\Rightarrow T=1.57079632679\ s$

Using exponential decay formula

$N=N_0e^{\dfrac{-bt}{m}}$

Final amplitude = Initial times decay

$\dfrac{1}{e}0.2=0.2e^{\dfrac{-0.015t}{2\times 0.25}}\\\Rightarrow 0.2=0.2e^{\frac{-0.015t}{2\cdot \:0.25}+1}\\\Rightarrow e^{\frac{-0.015t}{2\cdot \:0.25}+1}=1\\\Rightarrow \ln \left(e^{\frac{-0.015t}{2\cdot \:0.25}+1}\right)=\ln \left(1\right)\\\Rightarrow \left(\frac{-0.015t}{2\cdot \:0.25}+1\right)\ln \left(e\right)=\ln \left(1\right)\\\Rightarrow \frac{-0.015t}{2\cdot \:0.25}+1=\ln \left(1\right)\\\Rightarrow -\frac{0.015t}{0.5}=-1\\\Rightarrow -0.000225t=-0.0075\\\Rightarrow t=33.33\ s$

The time taken is 33.33 seconds

7 0

4 years ago

a .6 kg ball has a speed of 2 m/s at point a and kinetic energy of 7.5 j at point b. determine the following: the balls speed

Vladimir79 [104]

Answer:

Can You not Answer yourself

3 0

4 years ago

Concept Development

Ostrovityanka [42]

Answer:

The answer is below

Explanation:

The main difference between a liquid and a gas is that when a liquid is under pressure, its volume "won't change apparently. The reason is that the distance between the molecules of a liquid is relatively small, and the molecules of a liquid extensively withstand the compressive forces. This is similar to the distance between the molecules of a solid."

3 0

3 years ago

Two train whistles have identical frequencies of 1.85 102 Hz. When one train is at rest in the station and the other is moving n

Makovka662 [10]

Answer:

Explanation:

frequency of whistle = 1.85 x 10² = 185 Hz

frequency of beat heard = 8 beat /s . No of beat produced is equal to difference of frequencies of two sound source . Here difference is created due to Doppler effect . One of the train is moving so it will have apparent frequency which is different one from its original frequency .

When the moving train is approaching the observer , its frequency will be higher . As beat is heard at the rate of 8 beats / s , apparent frequency of approaching train will be 185 + 8 = 193 Hz .

Applying Doppler's formula of apparent frequency ,

193 = 185 x V / ( V - v ) , where V is velocity of sound and v is velocity of train .

193 V - 193 v = 185 V

193 v = 8 V

v = 8 x V / 193

= 8 x 343 / 193

= 14.21 m /s

Second possibility is that apparent velocity is less ie 185 - 8 = 177 Hz

In that case moving train will be moving away from observer . If its velocity be v

177 = 185 x V / ( V + v )

177 V + 177 v = 185 V

v = 8 x 343 / 177

= 15.50 m /s .

6 0

4 years ago

Which one of the following accurately describes the force of gravity? A. The force of gravity is slightly lower at the bottom of

AfilCa [17]

Choice ' C ' is a correct statement.
The other choices aren't.

6 0

4 years ago