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Harrizon [31]
3 years ago
8

Need help with science questions!

Physics
1 answer:
natta225 [31]3 years ago
3 0

Answer:

A.  Moving the mass from Point C to B, although it involves a greater distance, requires less force to do the same amount of work.

Explanation:

The amount of work will be the same either way.  By going from C to B, the mover will exert less force over a greater distance, which is easier than exerting a greater force over a shorter distance.

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vA 61.2-kg circus performer is fired from a cannon that is elevated at an angle of 57.8 ° above the horizontal. The cannon uses
dsp73

Answer:

The effective spring constant of the firing mechanism is 1808N/m.

Explanation:

First, we can use kinematics to obtain the initial velocity of the performer. Since we know the angle at which he was launched, the horizontal distance and the time in which it's traveled, we can calculate the speed by:

v_0_x=\frac{x}{t}\\ \\v_0\cos\theta=\frac{x}{t}\\\\v_0=\frac{x}{t\cos\theta}

(This is correct because the horizontal motion has acceleration zero). Then:

v_0=\frac{20.8m}{(2.60s)\cos57.8\°}\\\\v_0=15.0m/s

Now, we can use energy to obtain the spring constant of the firing mechanism. By the conservation of mechanical energy, considering the instant in which the elastic band is at its maximum stretch as t=0, and the instant in which the performer flies free of the bands as final time, we have:

E_0=E_f\\\\U_e=K\\\\\frac{1}{2}kx^2=\frac{1}{2}mv^2\\\\\implies k=\frac{mv^2}{x^2}

Then, plugging in the given values, we obtain:

k=\frac{(61.2kg)(15.0m/s)^2}{(2.76m)^2}\\\\k=1808N/m

Finally, the effective spring constant of the firing mechanism is 1808N/m.

3 0
3 years ago
To meet a U.S. Postal Service requirement, employees' footwear must have a coefficient of static friction of 0.5 or more on a sp
motikmotik

Answer:

0.79 s

Explanation:

We have to calculate the employee acceleration, in order to know the minimum time. According to Newton's second law:

\sum F_x:f_{max}=ma_x\\\sum F_y:N-mg=0

The frictional force is maximum since the employee has to apply a maximum force to spend the minimum time. In y axis the employee's acceleration is zero, so the net force is zero. Recall that f_{max}=\mu N

Now, we find the acceleration:

\mu N=ma_x\\\mu mg=ma_x\\a_x=\mu g\\a_x=0.83(9.8\frac{m}{s^2})\\a_x=8.134\frac{m}{s^2}

Finally, using an uniformly accelerated motion formula, we can calculate the minimum time. The employee starts at rest, thus his initial speed is zero:

x=v_0t+\frac{1}{2}a_xt^2\\2x=a_xt^2\\t=\sqrt{\frac{2x}{a}}\\t=\sqrt{\frac{2(3.2m)}{8.134\frac{m}{s^2}}}\\t=0.79 s

8 0
4 years ago
A ball is thrown upward with an initial velocity of +9.8 m/s. How high does it reach before it starts descending?
aksik [14]
Hope this helps you.

3 0
3 years ago
If the moon is a full moon tonight what will be the moon one week later waxing or waning
tatiyna

-- Starting from nothing (New Moon), the moon's shape grows ('waxes')
for half of the cycle, until it's full, and then it shrinks ('wanes') for the next
half of the cycle.

-- The moon's complete cycle of phases runs 29.53 days . . . roughly
four weeks.

-- So, beginning from New Moon, it spends about two weeks waxing until
it's full, and then another two weeks waning until it's all gone again.
 
-- After a Full Moon, the moon is waning for the next two weeks.  So it's
definitely <em>waning</em> at <em><u>one week</u></em> after Full.


5 0
3 years ago
According to the Can Manufacturers Institute, the energy used to make an aluminum can from recycled aluminum is 5% of the energy
ololo11 [35]

Answer:

H = 109.2 TJ.

Explanation:

Please see the attachment below.

4 0
3 years ago
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