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kirill115 [55]
2 years ago
6

A body is dropped from a height of 30m. What is the velocity of the body after it has covered a distance of 20 m? (Given g= 10 m

/s 2)
please fast
Physics
2 answers:
Veronika [31]2 years ago
7 0

Answer:

approximately 19.8  m/s

If using g = 10 m/s^2, the answer rounds to 20 m/s

Explanation:

You can use the kinematic formula that relates distance covered, velocities and acceleration (without time dependence) given by:

v_f^2-v_i^2=2\,*\,a\,*displacement

which in our case becomes:

v_f^2-0=2\,*\,(9.8\,\frac{m}{s^2}) \,*(20\,m)\\v_f^2=392\\v_f\approx 19.8\,\frac{m}{s}

If using g = 10 m/s^2, the answer is 20 m/s

den301095 [7]2 years ago
7 0

Answer:

the velocity is 20m/s

Explanation:

data given

  1. Height (h)=20m
  2. Gravity (g)=10m/s2
  3. velocity v = 0
  4. velocity u =?

v2 = u2 - 2gh

0 = u2 - 2 (10)(20)

0 = u2 - 400

400 = u2

20m/s = u

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A block of mass 4 kilograms is initially moving at 5m/s on a horizontal surface. There is friction between the block and the sur
Dmitriy789 [7]

Answer:

d = 2.54 [m]

Explanation:

Through the theorem of work and energy conservation, we can find the work that is done. Considering that the energy in the initial state is only kinetic energy, while the energy in the final state is also kinetic, however, this is zero since the body stops.

E_{k1}+W=E_{k2}\\

where:

W = work [J]

Ek1 = kinetic energy at initial state [J]

Ek2 = kinetic energy at the final state = 0.

We must remember that kinetic energy can be calculated by means of the following expression.

\frac{1}{2} *m*v^{2}-W=0\\W= \frac{1}{2} *4*(5)^{2}\\W= 50 [J]

We know that work is defined as the product of force by distance.

W=F*d

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F = force [N]

d = distance [m]

But the friction force is equal to the product of the normal force (body weight) by the coefficient of friction.

f=m*g*0.5\\f = 4*9.81*0.5\\f = 19.62 [N]

Now solving the equation for the work.

d=W/F\\d = 50/19.62\\d = 2.54[m]

4 0
3 years ago
When you throw a ball up in the air, it travels up and then stops instantaneously before falling back down. At the point where i
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The forces that resist the motion of the ball in the upward direction are the force of gravity and air resistance. The ball will instantaneously come to rest when the velocity of the ball reduces to zero.

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3 0
3 years ago
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4
tensa zangetsu [6.8K]

Answer:

C. amount of charge on the source charge.

Explanation:

Electric field lines can be defined as a graphical representation of the vector field or electric field.

Basically, it was first introduced by Michael Faraday and it is typically a curve drawn to the tangent of a point is in the direction of the net field acting on each point.

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