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A 250.0 kg mass is fired horizontally off a 40.0 cliff with a velocity of 30.0m/s. a....

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l70295100 | Student, Grade 12 | Honors

Posted July 12, 2013 at 3:12 AM via web

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A 250.0 kg mass is fired horizontally off a 40.0 cliff with a velocity of 30.0m/s.

a. Determine the time in the air before it hits the ground. (in s)

b. Dtermine the distance from the bottom of the cliff it lands. (in m)

Tagged with kinematic, physics, science

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justaguide | College Teacher | (Level 2) Distinguished Educator

Posted July 12, 2013 at 3:34 AM (Answer #1)

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The velocity of the object when it is fired horizontally off the cliff is 30 m/s. The mass of the object is 250 kg and the height of the cliff is 40 m.

As the mass leaves the edge of the cliff there is a downward acceleration of 9.8 m/s^2 due to the gravitational pull of the Earth. If the time taken by the object to hit the ground is t, use the formula s = u*t + (1/2)*a*t^2, here u = 0, a = 9.8

40 = (1/2)*9.8*t^2

=> t = `sqrt(80/9.8)`

=> `t ~~ 20/7` s

The horizontal distance from the cliff where the object lands is given by `30*(20/7)` = `600/7` m

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