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3 years ago

A baseball starts from rest and rolls 40.0 m down a hill in 10.0 seconds what is the acceleration

1 answer:

3 0

Acceleration is velocity over time. in order to find velocity, you divide distance over time
$v = \frac{d}{t} = \frac{40}{10} = 4 \\ a = \frac{v}{t} = \frac{4}{10} = 0.4 \: \frac{m}{ {s}^{2} }$

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A flywheel in the form of a uniformly thick disk of radius 1.33 m1.33 m has a mass of 70.6 kg70.6 kg and spins counterclockwise

ladessa [460]

Answer:

The constant torque required to stop the disk is 8.6 N-m in clockwise direction .

Explanation:

Let counterclockwise be positive direction and clockwise be negative direction .

Given

Radius of disk , r = 1.33 m

Mass of disc , m = 70.6 kg

Initial angular velocity , $\omega_i =217 rpm$

Final angular velocity , $\omega_f =0\, rpm$

Time taken to stop , t = 2.75 min

Let $\alpha$ be the angular acceleration

We know

$\omega _f=\omega _i+\alpha t$

=> $0=217+2.75\alpha =>\alpha = -78.9\frac{rev}{min^{2}}$

=> $\alpha =-\frac{78.9\times 2\pi}{60\times 60}\frac{rad}{s^{2}}=-0.138 \frac{rad}{s^{2}}$

Torque required to stop is given by

$\tau =I\alpha$

where moment of inertia , $I=\frac{mr^{2}}{2}=\frac{70.6\times 1.33^{2}}{2}kg.m^{2}=62.5 kg.m^{2}$

=> $\therefore \tau =-0.138\times 62.5\, N.m=-8.6\, N.m$

Thus the constant torque required to stop the disk is 8.6 N-m in clockwise direction .

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3 years ago

You can use the curved part of a spoon as a mirror because it ________ light.

zhenek [66]

Answer:

Reflects

Explanation:

A metal spoon looks very shiny because its surface is very smooth, which is why it acts like a mirror and reflects light very well.

8 0

2 years ago

Read 2 more answers

A crate of mass 50kg is pushed along a floor with a force of 20N for a distance of

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Answer:

F=50kg

D=5m

W=FD

therefore work done is 250Nm

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2 years ago

1. Calculate the mechanical advantage of a machine that has an input force of 13 N and

Helga [31]

Answer:

52 N output

Explanation: 65-13=52

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3 years ago

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The inner and outer surfaces of a cell membrane carry a negative and positive charge, respectively. Because of these charges, a

BlackZzzverrR [31]

Answer:

E = 8.5 * 10^6 V/m

Explanation:

In general we have the following relation between the Electric Field and the Elecric Potential:

$\int\limits^2_1 {\vec{E} \cdot\vec{dl}} = V_{2} -V_{1}$

Due to the vector nature of the electric filed, we can only know the mean Electric field E across the membrane, and take it out from the integral, that is:

E = (ΔV)/L

Where L is the thickness of the membrane and ΔV is the potential difference.

Therefore:

E = 8.53933*10^6 V/m

rounding to the first tenth:

E = 8.5 * 10^6 V/m

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3 years ago