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just olya [345]

4 years ago

13

The manufacturer of a bulletproof vest wants the vest to be able to stop a bullet with a mass of 0.4 kg and a velocity of 1800 m

/s. what is the momentum of this bullet?
a. 720 kg×m/s
b. 740 kg×m/s
c. 820 kg×m/s
d. 4500 kg×m/s

1 answer:

11111nata11111 [884]4 years ago

7 0

We know that momentum = mass times velocity
So a. 720 kgm/s

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What is the mass of a baseball that has a kinetic energy of 105 J and is traveling at 10 m/s?

kkurt [141]

Answer:

$\boxed {\boxed {\sf 2.1 \ kilograms}}$

Explanation:

Kinetic energy is the energy an object possesses due to motion. The formula 1/2 the product of mass and the squared velocity.

$E_k=\frac{1}{2} mv^2$

We know the baseball's kinetic energy is 105 Joules. It is also traveling at a velocity of 10 meters per second. `

First, convert the units of Joules to make unit cancellation easier later in the problem. 1 Joule (J) is equal to 1 kilogram square meter per square second (kg*m²/s²). The baseball's kinetic energy of 105 J is equal to 105 kg*m²/s².

Now we know 2 values:

$E_k= 105 \ kg*m^2/s^2$

$v= 10 \ m/s$

Substitute these values into the formula.

$105 \ kg*m^2/s^2= \frac{1}{2} m (10 \ m/s)^2$

Now we need to solve for m, the mass. Solve the exponent.

(10 m/s)²= 10 m/s * 10 m/s = 100 m²/s²

$105 \ kg *m^2/s^2 = \frac{1}{2} m (100 \ m^2/s^2)$

Multiply on the right side.

$105 \ kg *m^2/s^2 = m (\frac{1}{2} * 100 \ m^2/s^2)$

$105 \ kg *m^2/s^2 = m (50 \ m^2/s^2)$

The variable, m, is being multiplied by 50 square meters per square second. The opposite of multiplication is division, so we divide both sides by that value.

$\frac {105 \ kg *m^2/s^2 }{50 \ m^2/s^2}= \frac{ m (50 \ m^2/s^2)}{50 \ m^2/s^2}$

$\frac {105 \ kg *m^2/s^2 }{50 \ m^2/s^2}= m$

The units of square meter per square second will cancel out.

$\frac {105 }{50} \ kg= m$

$2.1 \ kg=m$

The mass of the baseball is <u>2.1 kilograms. </u>

5 0

3 years ago

Electrons in excited hydrogen atoms are in the

Sidana [21]

I can see three different transitions here:

3 --> 1

3 --> 2
followed by
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So we should expect to see three different 'colors'
being emitted from this excited mob.

4 0

3 years ago

With a total force of 20,000 newtons, an airplane has a mass of 1,200 kg. What is its acceleration?

swat32

Answer:

<h3>The answer is 16.67 m/s²</h3>

Explanation:

The acceleration of an object given it's mass and the force acting on it can be found by using the formula

$a = \frac{f}{m} \\$

f is the force

m is the mass

From the question we have

$m = \frac{20000}{1200} = \frac{200}{12} \\ = 16.66666...$

We have the final answer as

<h3>16.67 m/s²</h3>

Hope this helps you

8 0

3 years ago

In a new scenario, the block only makes it (exactly) half-way through the rough spot. How far was the spring compressed from its

Mila [183]

Answer: hello below is the missing part of your question

A mass m = 10 kg rests on a frictionless table and accelerated by a spring with spring constant k = 5029 N/m. The floor is frictionless except for a rough patch. For this rough path, the coefficient of friction is μk = 0.49. The mass leaves the spring at a speed v = 3.4 m/s.

answer

x = 0.0962 m

Explanation:

<em>First step :</em>

Determine the length of the rough patch/spot

F = Uₓ (mg)

and w = F.d = Uₓ (mg) * d

hence;

d( length of rough patch) = w / Uₓ (mg) = 46.55 / (0.49 * 10 * 9.8) = 0.9694 m

<em>next : </em>

work done on unstretched spring length

Given that block travels halfway i.e. d = 0.9694 / 2 = 0.4847 m

w' = Uₓ (mg) * d

= 0.49 * 10 * 9.81 * 0.4847 = 23.27 J

also given that the Elastic energy of spring = work done ( w')

1/2 * kx^2 = 23.27 J

x = $\sqrt{\frac{2*23.27}{5029} }$ = 0.0962 m

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3 years ago

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IrinaVladis [17]

Vector is perpendicular to x axis or i component.

Hence i component is 0

j component is 63.5

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3 years ago