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Dima020 [189]
2 years ago
15

A child is stationary on a swing. The child is given a push by his brother to start him swinging. His brother applies a steady f

orce of 84 N over a distance of 0.25 m. Calculate the work done by this force.
Physics
1 answer:
torisob [31]2 years ago
3 0
The formula is M=Fd
so we have F=84N and d=0.25m
Now we just replace F and d into the formula M=84N×0.25m
And the last thing we do is calculate it
M=21Nm
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3 0
2 years ago
Calculate the minimum average power output necessary for a person to run up a 12.0 m long hillside, which is inclined at 25.0° a
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Answer:

Power, P = 924.15 watts

Explanation:

Given that,

Length of the ramp, l = 12 m

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Time, t = 3 s

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h=l\ sin\theta

h=12\times \ sin(25)

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Let P is the power output necessary for a person to run up long hill side as :

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P=\dfrac{55.8\times 9.8\times 5.07}{3}

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2 years ago
Two small diameter, 10gm dielectric balls can slide freely on a vertical channel each carry a negative charge of 1microcoulomb.
dimulka [17.4K]

Answer:

The distance of separation is d = 0.092 \ m

Explanation:

The mass of the each ball is  m= 10 g  =  0.01 \ kg

 The negative charge on each ball is q_1 =q_2=q =  1 \mu C  =  1 *10^{-6} \ C

Now we are told that the lower ball is  restrained from moving this implies that the net force acting on it is  zero

Hence the gravitational force acting on the lower ball is equivalent to the electrostatic force i.e

          F =  \frac{kq_1 * q_2}{d}

=>       m* g  =  \frac{kq_1 * q_2}{d}

here k the the coulomb's  constant with a value  k = 9*10^{9} \ kg\cdot m^3\cdot s^{-4}\cdot A^2.

So  

      0.01 * 9.8  =  \frac{ 9*10^9 *[1*10^{-6} * 1*10^{-6}]}{d}

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2 years ago
A 35 g steel ball is held by a ceiling-mounted electromagnet 4.0 m above the floor. A compressed-air cannon sits on the floor, 4
HACTEHA [7]

Answer:

7.9 m/s

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When both balls collide, they have spent the same time for their motions.

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Motion of plastic ball

This has two components: a vertical and a horizontal.

The vertical motion is under gravity.

Considering the vertical motion,

Initial velocity, <em>u </em>= ?

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