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3 years ago

15

True or false: If the net external force on a system is zero, then the momentum of a system is constant even if objects in the s

ystem collide and exert forces on one another.

1 answer:

lisabon 2012 [21]3 years ago

3 0

Answer:

True: if no external forces act on a system of objects then the total momentum of the system is unchanged.

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A 1000-kg whale swims horizontally to the right at a speed of 6.0 m/s. It suddenly collides directly with a stationary seal of m

anzhelika [568]

Answer:

Momentum after collision will be 6000 kgm/sec

Explanation:

We have given mass of the whale = 1000

Initial velocity v = 6 m/sec

It collides with other mass of 200 kg which is at stationary

Initial momentum of the whale = 1000×6 = 6000 kgm/sec

We have to find the momentum after collision

From conservation of momentum

Initial momentum = final momentum

So final momentum = 6000 kgm/sec

5 0

3 years ago

Suppose you add two vectors A and B . What relative direction between them produces the resultant with the greatest magnitude? W

Akimi4 [234]

Answer:

Same direction to produce maximum magnitude and opposite direction to produce minimum magnitude

Explanation:

Let a be the angle between vectors A and B. Generally when we add A to B, we can split A into 2 sub vectors, 1 parallel to B and the other perpendicular to B.

Also let A and B be the magnitude of vector A and B, respectively.

We have the parallel component after addition be

Acos(a) + B

And the perpendicular component after addition be

Asin(a)

The magnitude of the resulting vector would be

$\sqrt{(Acos(a) + B)^2 + (Asin(a))^2}$

$= \sqrt{A^2cos^2a + B^2 + 2ABcos(a) + A^2sin^2a}$

$= \sqrt{A^2(cos^2a + sin^2a) + B^2 + 2ABcos(a)}$

$= \sqrt{A^2 + B^2 + 2ABcos(a)}$

As A and B are fixed, the equation above is maximum when cos(a) = 1, meaning a = 0 degree and vector A and B are in the same direction, and minimum with cos(a) = -1, meaning a = 180 degree and vector A and B are in opposite direction.

8 0

4 years ago

An object of mass 1.5 kg rests on a shelf where it has a gravitational potential energy of 7 joules. An object of mass 4.5 kg is

bija089 [108]

Answer:

C. 21 Joules

Explanation:

We apply the formula to calculate the potential energy (Ep):

Ep=m*g*h

Where:

Ep : potential energy in Joules (J)

m :mass in kilograms (kg)

g acceleration due to gravity (m/s²)

h: height in meters (m)

Calculation of the height (h)

Ep = m*g*h

7 = (1.5 )*(9.8) *(h )

7 = (14.7) (h )

h = 7 / (14.7)

h= 0.476 m

Gravitational potential energy of the second object

Ep = m*g*h

Ep = (4.5 )*(9.8) *(0.476 )

Ep = (4.5 )*(9.8) *(0.476 )

Ep = 21 J

6 0

4 years ago

PLEASE HELLPPP ITS FIR A FINAL 3.Speed (v) abs wavelength ( λ ) and the frequency (f) of sound are related asRequired to answer.

Aliun [14]

Answer:

B. v = λ X f

<em><u>Hope this helps! </u></em>

8 0

3 years ago

A 3.0-kilogram mass is traveling in a circle of

dmitriy555 [2]

Answer:

$a=20\ m/s^2$

Explanation:

Given that,

The mass of an object, m = 3 kg

The radius of a circle, r = 0.2 m

The speed of the object, v = 2 m/s

We need to find the centripetal acceleration. Its formula is given by :

$a=\dfrac{v^2}{r}\\\\a=\dfrac{(2)^2}{0.2}\\\\a=20\ m/s^2$

So, the centripetal acceleration is $20\ m/s^2$ .

4 0

3 years ago