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3 years ago

15

Two vectors A and B are directed such that there is an angle θ between them. show answer Incorrect Answer Which of the following

statements is true about the scalar product of these two vectors?

1 answer:

Troyanec [42]3 years ago

8 0

Answer:

Scalar product is between ║A║ ║ B║ and -║A║ ║ B║

Explanation:

Dot product between vec A and vec B is

A.B = ║A║ ║ B║ cos θ

Here, both ║A║ and ║B║ are positive and value of cos θ depends upon θ and lies between 1 and -1

So, Scalar product is between ║A║ ║ B║ and -║A║ ║ B║

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The model of the atom proposed by Greek philosophers appears similar to the model proposed centuries later by Dalton. What was t

Sladkaya [172]

The main difference between the model of the atom proposed by Greek philosophers and the model proposed centuries later by Dalton is that the Greek one was mainly speculative and philosophical - it wasn't based on real evidence, but on their suggestions and thoughts about the matter. On the other hand, Dalton had the means to prove his theory using viable evidence, not just speculations.

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3 years ago

Susan's 12.0 kg baby brother Paul sits on a mat. Susan pulls the mat across the floor using a rope that is angled 30∘ above the

Pavlova-9 [17]

Answer:1.71 m/s

Explanation:

Given

mass of Susan $m=12 kg$

Inclination $\theta =30^{\circ}$

Tension $T=29 N$

coefficient of Friction $\mu =0.18$

Resolving Forces Along x axis

$F_x=T\cos \theta -f_r$

where $f_r=friction\ Force$

$F_y=mg-N-T\sin \theta$

since there is no movement in Y direction therefore

$N=mg-T\sin \theta$

and $f_r=\mu N$

Thus $F_x=T\cos \theta -\mu N$

$F_x=29\cos (30)-\0.18\times (12\times 9.8-29\sin (30))$

$F_x=25.114-18.558$

$F_x=6.556 N$

Work done by applied Force is equal to change to kinetic Energy

$F_x\cdot x=\frac{1}{2}\cdot mv_f^2-\frac{1}{2}\cdot mv_i^2$

$6.556\times 2.7=\frac{1}{2}\cdot 12\times v_f^2$

$v_f^2=\frac{6.556\times 2.7\times 2}{12}$

$v_f^2=2.95$

$v_f=1.717 m/s$

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2 years ago

A 1500kg car double its speed from 50km/h to 100km/h. By how many times does the kinetic energy from the car's forward motion in

Rashid [163]

Answer:

Explanation:

Inital KE = (1/2) m v^2 = (1/2) * 1500 * 50^2 = 1,875,000 J

Final KE = (1/2) * 1500 * 100^2 = 7,500,000 J

But ,

4 * 1875000 = 7500000

so the KE has increased by 4 times.

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2 years ago

Read 2 more answers

Second and third class levers are differentiated by __________. a. the location of the fulcrum b. the location of the load c. th

strojnjashka [21]

Answer:

the answer is b

Explanation:

Second and third class levers are differentiated by <u>the location of the </u><u>load.</u>

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2 years ago

The ball of a ballpoint pen is 0.5 mm in diameter and has an ASTM grain size of 12. How many grains are there in the ball

Fudgin [204]

Given :

The ball of a ballpoint pen is 0.5 mm in diameter and has an ASTM grain size of 12.

To Find :

How many grains are there in the ball?

Solution :

Volume of ball of the ballpoint is :

$V = \dfrac{4 \pi r^3}{3}\\\\V = \dfrac{4\times 3.14 \times 0.5^3}{3}\ mm^3\\\\V = 0.523\ mm^3$

Now, grain size of 12 has about 520000 grains/mm³.

Therefore, number of grains are :

$n = 520000\times 0.523\ grains\\\\n = 271960\ grains$

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2 years ago