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3 years ago

11

John is preparing for his way to school. His house is 30 km away. What time will he be in school if he leaves his house at 6:30

AM and travels at an average speed of 40 km/hr?

1 answer:

Goshia [24]3 years ago

7 0

Answer:

Jio will be at school at 7:15 a.m.

Explanation:

Formula:

t= s/v =(30km)/(40km/h) =0.75•60min=45min.

Then, Jio will be at school at 6:30a.m. + 45min =7:15a.m.

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Two objects were lifted by a machine. One object had a mass of 5000 kg, and was lifted at a speed of 2 m/sec. The other had a ma

Leokris [45]

Equation for ke = 1/2mv^2
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so I know you can solve this either by using Vox or Voy. I'm getting 3.08s when using Vox and 3.14s for Voy way. For Voy I'm usi

Tatiana [17]

The person's horizontal position is given by

$x=v_0\cos40^\circ t$

and the time it takes for him to travel 56.6 m is

$56.6\,\mathrm m=\left(24.0\,\dfrac{\mathrm m}{\mathrm s}\right)\cos40^\circ t\implies t=3.08\,\mathrm s$

so your first computed time is the correct one.

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$v_y=v_{0y}-gt$

which tells us that he would reach the ground at about $t=3.15\,\mathrm s$ . In this time, he would have traveled

$x=v_{0x}(3.15\,\mathrm s)=57.9\,\mathrm m$

But we're told that he is caught by a net at 56.6 m, which would mean that the net cannot have been placed at the same height from which he was launched. However, it's possible that the moment at which he was launched doesn't refer to the moment the cannon went off, but rather the moment at which the person left the muzzle of the cannon a fraction of a second after the cannon was set off. After this time, the person's initial vertical velocity $v_{0y}$ would have been a bit smaller than $\left(24.0\,\frac{\mathrm m}{\mathrm s}\right)\sin40^\circ$ .

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2 years ago

A spring has a spring constant of 53N/m. How much elastic potential energy is stored in the spring in the spring when it is comp

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Answer:11686.5 joules

Explanation:

elastic constant(k)=53N/m

extension(e)=21m

Elastic potential energy=(k x e^2)/2

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Elastic potential energy=(53x21x21)/2

Elastic potential energy=23373/2

Elastic potential energy=11686.5

Elastic potential energy is 11686.5 joules

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3 years ago

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NeTakaya

Answer:

Grow plants where little light is available

Explanation:

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a race car accelerates uniformly from 18.5 m/s to 46.1m/s in 2.47 seconds detrrmine the acceleration of the car and distance tra

LenaWriter [7]

Because acceleration is constant, the acceleration of the car at any time is the same as its average acceleration over the duration. So

$a=\dfrac{\Delta v}{\Delta t}=\dfrac{46.1\,\frac{\mathrm m}{\mathrm s}-18.5\,\frac{\mathrm m}{\mathrm s}}{2.47\,\mathrm s}=11.2\,\dfrac{\mathrm m}{\mathrm s^2}$

Now, we have that

${v_f}^2-{v_0}^2=2a\Delta x$

so we end up with a distance traveled of

$\left(46.1\,\dfrac{\mathrm m}{\mathrm s}\right)^2-\left(18.5\,\dfrac{\mathrm m}{\mathrm s}\right)^2=2\left(11.2\,\dfrac{\mathrm m}{\mathrm s^2}\right)\Delta x$

$\implies\Delta x=79.6\,\mathrm m$

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