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4 years ago

Which observation supported WegenerÍs theory of continental drift?

1 answer:

3 0

"Identical fossils were found on continents that were far apart" is the one observation among the following choices given in the question that <span>supported WegenerÍs theory of continental drift. The correct option among all the options that are given in the question is the fourth option or the last option.</span>

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A 1600 kg car with the brakes applied comes to a stop in 4.20 seconds. During these 4.20 seconds the force of friction slowing d

Natasha2012 [34]

Answer:

The change in momentum of the car is 16380.8 kg.m/s

Explanation:

Given;

mass of the car, m = 1600 kg

time of motion, t = 4.20s

force of friction on the car, F = 3900 N

final velocity of the car after the brakes were applied, v = 0

The initial velocity of the car during the motion is calculated as;

$F = ma = \frac{mu}{t} \\\\mu = Ft\\\\u = \frac{Ft}{m} \\\\u = \frac{3900\times 4.2}{1600} \\\\u = 10.238 \ m/s$

The change in momentum of the car is calculated as;

ΔP = mu

ΔP = 1600 x 10.238

ΔP = 16380.8 kg.m/s

8 0

3 years ago

While riding a bike down a steep hill at 9ms you skid to a stop in 3.2 seconds. How far did the bike slide? Assume uniform accel

castortr0y [4]

Answer:

24.30 m

Explanation:

v(final)=v(initial)+at

0 m/s= 9 m/s +a(3.2s)

a=-2.81 m/s^2

delta x= vt+ (1/2)at^2

=(9 m/s * 3.2 s)+ (.5* -2.81 m/s^2 * 3.2s)

=24.30 m

3 0

4 years ago

How fast, in meters per second, does an observer need to approach a stationary sound source in order to observe a 1.6 % increase

morpeh [17]

Answer:

The value is $v_o = 5.488 \ m/s$

Explanation:

From the question we are told that

The emitted frequency increased by $\Delta f = 1.6 \% = 0.016 \$

Let assume that the initial value of the emitted frequency is

$f = 100\% = 1$

Hence new frequency will be $f_n = 1 + 0.016 = 1.016$

Generally from Doppler shift equation we have that

$f_1 = [\frac{ v \pm v_o}{v \pm + v_s } ] f$

Here v is the speed of sound with value $v = 343 \ m/s$

$v_s$ is the velocity of the sound source which is $v_s = 0 \ m/s$ because it started from rest

$v_o$ is the observer velocity So

Generally given that the observer id moving towards the source, the Doppler frequency becomes

$f_1 = [\frac{ v + v_o}{v + 0 } ] f$

=> $1.016 = [\frac{ 343 + v_o}{343 } ] * 1$

=> $v_o = 5.488 \ m/s$

8 0

3 years ago

Your backpack has a mass of 8 kg. You lift it from the ground to a height of

motikmotik

Answer:

the answer will be 5.6 j..

hope you like the answer.....

3 0

3 years ago

A 9.76-m ladder with a mass of 22.6 kg lies flat on the ground. A painter grabs the top end of the ladder and pulls straight upw

galben [10]

Answer:

Part a)

$\tau_{net} = 1397.1 Nm$

Part b)

$I = 702.06 kg m^2$

Explanation:

Part a)

Torque on the rod is due to two forces

(i) Due to weight of the rod at mid point

(ii) Due to external force applied at the end

Now we have

$\tau_{net} = FL - mg\frac{L}{2}$

$\tau_{net} = 254(9.76) - (22.6)(9.81)(\frac{9.76}{2})$

$\tau_{net} = 1397.1 Nm$

Part b)

As per Newton's law we know that

$\tau = I\alpha$

now we have

$1397.1 Nm = I(1.99 rad/s^2)$

$I = 702.06 kg m^2$

6 0

3 years ago