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3 years ago

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First, you will investigate purely vertical motion. The kinematics equation for vertical motion (ignoring air resistance) is giv

en by y(t)=y0+v0t−(1/2)gt2 , where y0=0 is the initial position, v0 is the initial speed, and g is the acceleration due to gravity. Drag the cannon downwards so it is at ground level, or 0 m (which represents the initial height of the object), then fire the pumpkin straight upward (at an angle of 90∘) with an initial speed of 14 m/s . How long does it take for the pumpkin to hit the ground?

1 answer:

AlladinOne [14]3 years ago

6 0

Answer: It takes 2.85 seconds.

Explanation: according to the question, the kinematics equation for vertical motion is

$y(t) = y_{0} + v_{0} .t - \frac{1}{2} .gt^{2}$

y₀ is the initial postion and equals 0 because it is fired at ground level;

v₀ is the initial speed and eqauls 14m/s;

g is gravity and it is 9.8m/s²;

y(t) is the final position and equals 0 because it is when the pumpkin hits the ground;

Rewriting the equation, we have:

0 + 14t - $\frac{1}{2}.9.8.t^{2}$ = 0

14t - 4.9t² = 0

t(14 - 4.9t) = 0

For this equation to be zero,

t = 0 or

14 - 4.9t = 0

- 4.9t = - 14

t = $\frac{14}{4.9}$

t = 2.86

It takes 2.86 seconds for the pumpkin to hit the ground.

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The gravitational force between the two spheres is 0.006 N

Explanation:

The magnitude of the gravitational force between two objects is given by

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For the two spheres in this problem, we have

$m_1 = 38,500 kg$

$m_2 = 15,400 kg$

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4 years ago

A stone is thrown from the top of a building with an initial velocity of 20 m/s downward. The top of the building is 60 m above

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Answer:

t = 2 s

Explanation:

In order to find the time taken by the stone to fall from the top of the building to the ground we can use 2nd equation of motion. 2nd equation of motion is as follows:

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s = height of building = 60 m

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Therefore,

60 m = (20 m/s)t + (0.5)(9.8 m/s²)t²

4.9t² + 20t - 60 = 0

solving this quadratic equation we get:

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Since, the time cannot be negative in magnitude.

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Answer:

a) 0.00996 m

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$E = 200GPa = 200\times10^9 Pa$

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If the 2.2m rod cannot stretch more than 0.0012 m, its maximum strain is

$\epsilon = \frac{\Delta L}{L} = \frac{0.0012}{2.2} = 0.000545455$

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