A pencil rolls off the edge of a desk with a horizontal velocity of 10m/s. The height of the desk is 2.5m. 1.How far away from the desk does the pencil hit theg

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Answer 1

Hi Tiara.

 

The pencil is a height of 2.5m off the ground and will immediately be effected by gravity on its fall. We can use this fact to determine how long the pencil was in the air.

 

h = 1/2*g*t^2

 

2.5 = 1/2*9.8*t^2

 

5 = 9.8*t^2

 

t^2 = 0.51

 

t = 0.71 seconds

 

The horizontal component of travel is constant. We know it was traveling 10m/s initially from the question, and based on the height from which it fell and gravity, we determined it was in the air for 0.71 seconds.

 

distance = rate*time

 

= 10m/s * 0.71 seconds = 7.1 meters.

 

That is a speedy pencil.