# 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...

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)

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### 1 Answer

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