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3 years ago

Date:

Physics

1 answer:

erica [24]3 years ago

4 0

Explanation:

Mass = m

Velocity = v

If Mass is increased 4 times = 4m

New velocity = 2v

Kinetic Energy

$\frac{1}{2}m {v}^{2}$

So it will be 1/2 × 4m × 2v × 2v

$8m {v}^{2}$

so Kinetic Energy will increase 4 times

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Superman lived on another planet where the acceleration due to gravity is 23.6 m/s2 . If a woman falls from a building that is 8

dusya [7]

Acceleration due to gravity = 2.6m/s²

Length of building = d = 88.3m

<span>Time he needed before she hits the ground = ?
we can find the time by using the formula;</span>

D = 1/2at²

Now putting the value;

<span>88.3 = (1/2) a t</span>²<span>

88.3 = 1/2 x 23.6 x t</span>²

t² = 88.3 / 11.8

= 7.48

<span>t = 2.735 seconds

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3 years ago

Provide at least one example of acceleration and explain why it would be considered a scalar or vector quantity.

Gelneren [198K]

Take gravity you are accelerated toward the ground. Since gravity has both a direction and a magnitude, then it is a vector.

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3 years ago

An iron vat is 11 m long at room temperature (20°C). How much longer is it when it contains boiling water at 1 atm pressure?

RoseWind [281]

Answer:

The change in length is 0.01056 m.

Explanation:

Given that,

Length = 11 m

Temperature = 20°C

Pressure = 1 atm

Boiling temperature = 100°C

We need to calculate the length

Using formula of change in linear expansion

$\dfrac{\Delta L}{L}=\alpha_{l}\Delta T$

$\Delta L=L\times\alpha_{l}\times(T_{f}-T_{i})$

Put the value into the formula

$\Delta L=11\times12\times10^{-6}\times(100-20)$

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$\Delta L=0.01056\ m$

Hence, The change in length is 0.01056 m.

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4 years ago

3V battery is used with a 15 ohm resistance.What is the current?

Pavlova-9 [17]

Answer:

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V= IR

3 = I × 15

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3 years ago

The Sears Tower is nearly 400 m high. How long would it take a steel ball to reach the ground if dropped on the top? What will b

kipiarov [429]

Answers:

a) 9.035 s

b) -88.543 m/s

Explanation:

The described situation is related to vertical motion (especifically free fall) and the equations that will be useful are:

$y=y_{o}+V_{o}t+\frac{1}{2}gt^{2}$ (1)

$V=V_{o}+gt$ (2)

Where:

$y=0$ is the final height of the steel ball

$y_{o}=400 m$ is the initial height of the steel ball

$V_{o}=0$ is the initial velocity of the steel ball (it was dropped)

$V$ is the final velocity of the steel ball

$t$ is the time it takes to the steel ball to reach the ground

$g=-9.8 m/s^{2}$ is the acceleration due to gravity

<u>Knowing this, let's begin with the answers:</u>

<h2>a) Time it takes the steel ball to reach the ground</h2>

We will use equation (1) with the conditions listed above:

$0=y_{o}+\frac{1}{2}gt^{2}$ (3)

Isolating $t$ :

$t=\sqrt{\frac{-2y_{o}}{g}}$ (4)

$t=\sqrt{\frac{-2(400 m)}{-9.8 m/s^{2}}}$ (5)

$t=9.035 s$ (6)

<h2>b) Final velocity of the steel ball</h2>

We will use equation (2) with the conditions explained above and the calculaated time:

$V=gt$ (7)

$V=(-9.8 m/s^{2})(9.035 s)$ (8)

$V=-88.543 m/s$ (9) The negative sign indicates the direction of the velocity is downwards

3 0

3 years ago