Question

A pencil is rolled off a table of height .92 m. If it has a horizontal speed of 1.4 m/s how long does it take the pencil to reach the ground?

A. 1.52 s
B. .43 s
C. .85 s
D. .66 s

Answer 1

Please help😩

Answer 2

ok notice that horizontal velocity doesn't have anything to do with this question

Answer 3

All you need is acceleration due to gravity of 9.8m/s^2. Since the distance is 0.92m you would calculate the time it takes for the pencil to fall and travel that distance by acceleration due to gravity which is 9.8m/^2

Answer 4

Your best bet is using DeltaD=viDelta(t)*1/2(a)deltat^2

Answer 5

Then apply the quadratic formula to solve for the t, and take the positive value. Not the negative one

Answer 6

Let me know if you'd like me to show that for you

Answer 7

Oh also note that vertical velocity is the only thing required in trying to answer this question you can ignore the horizontal velocity.

Answer 8

Horizontal velocity has absolutely no effect on the vertical velocity unless it has an angle of direction other than 90 degrees. In this case you would use the cosine law to account for the vertical velocity as well as horizontal velocity and manipulate the formulas to get the final answer. However for this particular question you don't need to even think about the horizontal velocity because in this question it is clearly revealed that the object has a "horizontal velocity" and not anything else.