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3 years ago

11

Number 10 and an explaination would be fabulous. thanks!

2 answers:

Sati [7]3 years ago

3 0

Linear momentum has to be conserved. It was zero before the thread eas burned ... when nothing was moving ... so the momentum of the masses moving in opposite directions has to add up to zero. ... Momentum = mass times speed. ... In one direction, you have 5 kg times 1/5 m/s= 1 kg-m/s. ... We need 1 kg-m/s in the other direction. ... 7 kg times speed = 1 kg-m/s. ... Can you finish it from here ?

UkoKoshka [18]3 years ago

3 0

The answer would be 1/7 m/s because the initial momentum in the objects is 0, then the final momentum of the objects must be 0. if the 5 kg object has a momentum of 1 (5 * 1/5) then the other object must be -1. The only velocity that will produce that result is -1/7 m/s, but since speed doesnt take into account the direction of an object.

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Olivia put a glass of water in the freezer. She left it there for three hours. When she returned, the water had turned to ice. W

Darya [45]

A. freezing, when water turns to ice the water is turning from a liquid to a solid.

7 0

3 years ago

A 26-g steel-jacketed bullet is fired with a velocity of 630 m/s toward a steel plate and ricochets along path CD with a velocit

Alecsey [184]

Answer:

F = - 3.53 10⁵ N

Explanation:

This problem must be solved using the relationship between momentum and the amount of movement.

I = F t = Δp

To find the time we use that the average speed in the contact is constant (v = 600m / s), let's use the uniform movement ratio

v = d / t

t = d / v

Reduce SI system

m = 26 g ( 1 kg/1000g) = 26 10⁻³ kg

d = 50 mm ( 1m/ 1000 mm) = 50 10⁻³ m

Let's calculate

t = 50 10⁻³ / 600

t = 8.33 10⁻⁵ s

With this value we use the momentum and momentum relationship

F t = m v - m v₀

As the bullet bounces the speed sign after the crash is negative

F = m (v-vo) / t

F = 26 10⁻³ (-500 - 630) / 8.33 10⁻⁵

F = - 3.53 10⁵ N

The negative sign indicates that the force is exerted against the bullet

5 0

3 years ago

The density of a certain type of plastic is 0.75 g/cm3 . If a sheet of this plastic is 10.0 m long, 1.0 m wide, and 1 cm thick,

Oksanka [162]

Answer:

7.5 g

Explanation:

8 0

2 years ago

Two in-phase loudspeakers that emit sound with the same frequency are placed along a wall and are separated by a distance of 5.0

e-lub [12.9K]

Answer:

$f = 421.8 Hz$

Explanation:

When she moved a distance of 1 m from mid point she observe first destructive interference due to two speakers

so we can say that path difference of sound due to two speakers will be equal to half of the wavelength

so path difference is given as

$\Delta L = {3.5^2 + 12^2}^{0.5} - {1.5^2 + 12^2}^{0.5}$

so it will be

$\Delta L = 12.5 - 12.093$

$\Delta L = 0.4066$

now we know that

$\frac{\lambda}{2} = 0.4066$

$\lambda = 0.813$

now frequency of sound is given as

$f = \frac{v}{\lambda}$

$f = \frac{343}{0.813}$

$f = 421.8 Hz$

4 0

3 years ago

A ball is thrown straight upward and rises to a maximum

Leviafan [203]

Answer:

Explanation:

As we know that the ball is projected upwards so that it will reach to maximum height of 16 m

so we have

$v_f^2 - v_i^2 = 2 a d$

here we know that

$v_f = 0$

also we have

$a = -9.81 m/s^2$

so we have

$0 - v_i^2 = 2(-9.81)(16)$

$v_i = 17.72 m/s$

Now we need to find the height where its speed becomes half of initial value

so we have

$v_f = 0.5 v_i$

now we have

$v_f^2 - v_i^2 = 2 a d$

$(0.5v_i)^2 - v_i^2 = 2(-9.81)h$

$-0.75v_i^2 = -19.62 h$

$0.75(17.72)^2 = 19.62 h$

$h = 12 m$

3 0

3 years ago