Question

A ball is in the air for 5.1s and it goes a distance of 70m. What is the highest point it reaches in the air?

Answer 1

@Brandonleu Is any other information given?

Answer 2

No thats all that is given in the problem.

Answer 3

This sounds like 1D motion but it seems like there's not enough information...

@wolfe8

Answer 4

Tom Brady throws a touchdown pass to Randy Moss in a football game. The pass follows a perfect projectile and is timed at 5.1s in the air. The distances that pass goes for is an astounding 70m! Figure out the highest point of the football as it is thrown down the field. Be sure to include all formulas and proper units while solving the problem.
Thats the full question.

Answer 5

ah, so projectile motion
this is going to need 2 equations and 2 unknowns

Answer 6

Assuming perfect parabolic path with no air resistance, the horizontal velocity is 70m / 5.1s = 9.8 m/s. It would reach its highest point half-way along the path (i.e. t = 2.55s). This is the same amount of time it would take to fall from its highest point. The distance an object can free fall in 2.55s is given by y=0.5g*t^2, g~9.8 m/s^2

Answer 7

@CliffSedge Hmm I didn't consider that; I was thinking along the lines of using the Range and Height equations to find the angle but that works too. Don't you usually stay in the math group?

@Brandonleu
@CliffSedge 's solution also works. What I was thinking was a bit too complicated.

Answer 8

I thought both directions would be needed too at first, that's why I started with the horizontal velocity, but it turns out it's not needed if you know the total hang time.

Answer 9

"@CliffSedge . . . Don't you usually stay in the math group?" - I suppose, but probably because it is more densely populated. Physics is actually my specialty.

Answer 10

A 2 pound rock is kicked off a ledge by a five year old boy. The height of the ledge to the ground is 75m. How long does it take the rock to hit the ground? Be sure to include all formulas and proper units while solving the problem.
How about this one?

Answer 11

Ask as new question.

Answer 12

\[\Delta y=75\]\[m=2~lb\times 0.453592~kg=0.907185~kg\]\[g=9.8m/s^2\]If you know kinematics you should be able to solve for the answer.

Answer 13

\[Correction:~\Delta y=75~m\]\[v_0=0m/s\]\[\Delta y={v_0}^2-\frac{1}{2}at\]a is g. Replace variables with the respective values shown above.

Answer 14

Correction- the squared is on the t, NOT the Vo

Answer 15

use the free-fall time as @cliffsedge suggests to find the vertical height

Answer 16

*brandonleu
u look like someone i know.... where r u from?

Answer 17

btw... why don't u go outside and test ur question?

Answer 18

I think he would wear himself out trying to throw a football 70m!

Answer 19

lol