A boy on the edge of a vertical cliff 20-m high throws a stone horizontally outwards with a speed of 20 m/s. It strikes the ground at what horizontal distance from the foot of the cliff? (Use g = 10 m/s2.)

Respuesta :

Answer:

Horizontal distance from the foot of the cliff is 40 m

Explanation:

Given :

Speed of stone [tex]v = 20\frac{m}{s}[/tex]

Vertical distance [tex]d = 20[/tex] m

Gravitational acceleration [tex]g = 10[/tex] [tex]\frac{m}{s^{2} }[/tex]

From the kinematics equation,

  [tex]d = v_{o} t + \frac{1}{2} at^{2}[/tex]

Where [tex]v_{o} =[/tex] initial velocity ( [tex]v_{o} = 0[/tex] )

So time take to fall down,

  [tex]t = \sqrt{\frac{2d}{a} }[/tex]

  [tex]t = \sqrt{4}[/tex]

  [tex]t = 2[/tex] sec

Now find horizontal distance travel by stone,

 [tex]x = vt[/tex]

 [tex]x = 20 \times 2[/tex]

 [tex]x = 40[/tex] m

Therefore, the horizontal distance travel by stone is 40 m

Lanuel

The horizontal distance at which the stone strikes the ground from the foot of the cliff is 40 meters.

Given the following data:

  • Displacement = 20 meters
  • Horizontal speed = 20 m/s.
  • Acceleration due to gravity = 10 [tex]m/s^2[/tex]

To find the horizontal distance at which the stone strikes the ground from the foot of the cliff:

First of all, we would calculate the time it took the stone to reach the ground by using the second equation of motion:

Mathematically, the second equation of motion is given by the formula;

[tex]S =ut +\frac{1}{2} at^2[/tex]

Where:

  • S is the displacement.
  • u is the initial velocity.
  • a is the acceleration.
  • t is the time measured in seconds.

Substituting the given parameters into the formula, we have;

[tex]20 = 0(t) + \frac{1}{2} 10t^2\\\\20 = 5t^2\\\\t^2=\frac{20}{5} \\\\t^2=4\\\\t=\sqrt{4}[/tex]

Time, t = 2 seconds

Now, we can find the horizontal distance:

[tex]Horizontal \;distance = horizontal \;speed \times time\\\\Horizontal \;distance =20 \times 2[/tex]

Horizontal distance = 40 meters

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