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Mekhanik [1.2K]

3 years ago

15

A skater slides across the ice with an initial velocity of 5.0 m/s. She slows 10 points

1 answer:

zvonat [6]3 years ago

7 0

Explanation:

Given that,

The initial velocity of a skater is, u = 5 m/s

She slows to a velocity of 2 m/s over a distance of 20 m.

We can find the acceleration of skater. It is equal to the rate of change of velocity. So, it can be calculated using third equation of motion as follows :

$v^2-u^2=2as$

a = acceleration

$a=\dfrac{v^2-u^2}{2s}\\\\a=\dfrac{(2)^2-(5)^2}{2\times 20}\\\\a=-0.525\ m/s^2$

So, her acceleration is $0.525\ m/s^2$ and she is deaccelerating. Also, her initial velocity is given i.e. 5 m/s.

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Question 12 (Mandatory) (5 points)

sergij07 [2.7K]

F = ma
F = (6kg) (3.5m/s2)
F = 21 N

7 0

3 years ago

Why do sound engineers use spongy materials in the walls? (1 point)

mihalych1998 [28]

Answer:

o to increase the frequency of sound waves. It increases the sound waves to a level of frequency that humans cannot hear so you won't be able to hear many things though the wall other then low noises like pounding.

Explanation:

I am in construction class as well as a student teacher for other construction type programs trust me :D

Brainiest would be appreciated

8 0

3 years ago

1. There is a famous intersection in Kuala Lumpur, Malaysia, where thousands of vehicles pass each hour. A 750 kg Tesla Model S

tigry1 [53]

Solution :

Let the positive $x-axis$ is along the East and the positive $y$ direction is along the north.

Given :

Mass of the Tesla car, $m_1$ = $750 \ kg$

Mass of the Ford car, $m_2 = 1250 \ kg$

Now let the initial velocity of Tesla car in the south direction be = $-v_1j$

The initial momentum of Tesla car, $p_1 = -750 \ v_1$

Let the initial velocity of Ford car in the east direction be = $v_2 \ i$

So the initial momentum of the Ford car is $p_2=1250\ v_2 \ i$

Therefore, the initial velocity of both the cars is $p_i = p_1+p_2$

$=1250 \ v_2 \ i - 750\ v_1 \ j$

Now the final velocity of both the cars is $v = 18 \ m/s$

So the vector form is :

$v = 18\cos 32\ i-18 \sin 32 \ j$

$= 15.26 \ i - 9.54 \ j$

Therefore the momentum after the accident is

$p_f=(m_1+m_2) \times v$

$=(750+1250) \times (15.26 \ i - 9.54 \ j)$

$= 30520\ i -19080\ j$

According to the law of conservation of momentum, we know

$p_i = p_f$

$1250 \ v_2 \ i - 750\ v_1 \ j$ $= 30520\ i -19080\ j$

$1250 \ v_2 = 30520$

$v_2=24.4 \ m/s$

From, $750\ v_1 = 19080$

We get, $v_1=25.4 \ m/s$

Therefore the speed of Tesla car before collision = 25.4 m/s

The speed of ford car before collision = 24.4 m/s

6 0

3 years ago

A solid sphere of brass (bulk modulus of 14.0 ✕ 1010 N/m2) with a diameter of 2.20 m is thrown into the ocean. By how much does

astra-53 [7]

Answer:

Diameter decreases by the diameter of 0.0312 m.

Explanation:

Given that,

Bulk modulus = 14.0 × 10¹⁰ N/m²

Diameter d = 2.20 m

Depth = 2.40 km

Pressure = ρ g h = 1030 × 9.81 × 2.4 × 1000

= 24.25 × 10⁶ N/m²

Volume = $\dfrac{4}{3} \pi r^3$

$\dfrac{\Delta V}{V}=\dfrac{(\Delta r)^3}{r^3}$

Bulk modulus is equal to

$B = -\dfrac{\Delta P}{\dfrac{\Delta V}{V} }$

now

$B = -\dfrac{24.25 \times 10^6}{\dfrac{(\Delta r)^3}{r^3} }$

$B = -\dfrac{24.25 \times 10^6}{\dfrac{(\Delta r)^3}{1.1^3} }$

$(\Delta r)^3 = \dfrac{24.25 \times 10^6 \times 1.1^3}{14.0 \times 10^{10}}$

Δ r = -0.0156 m

change in diameter

Δ d = -2 × 0.0156

Δ d = -0.0312 m

Diameter decreases by the diameter of 0.0312 m.

7 0

3 years ago

In an RL series circuit, an inductor of 3.54 H and a resistor of 7.76 Ω are connected to a 26.6 V battery. The switch of the cir

podryga [215]

Answer:

Energy stored in inductor will be 20.797 J

Explanation:

We have given inductance L = 3.54 H

And resistance R = 7.76 ohm

Battery voltage V = 26.6 VOLT

After very long time means at steady state inductor behaves as short circuit

So current $i=\frac{V}{R}=\frac{26.6}{7.76}=3.427Amp$

Now energy stored in inductor $E=\frac{1}{2}Li^2=\frac{1}{2}\times 3.54\times 3.427^2=20.797J$

So energy stored in inductor will be 20.797 J

4 0

4 years ago