I NEED HELP PLEASE, THANKS! :) A discus is thrown from a height of 4 feet with an initial velocity of 65 ft/s at an angle of 44° with the horizontal. How long will it take for the discus to reach the ground? (Show work)

  2.908 s

Step-by-step explanation:

The "work" is most easily done by a graphing calculator. We only need to tell it the equation of motion.

For speeds in feet per second, the appropriate equation for vertical ballistic motion is ...

  h(t) = -16t² +v₀t +s₀

where v₀ is the initial vertical velocity in ft/s and s₀ is the initial height in feet. The vertical velocity is the vertical component of the initial velocity vector, so is (65 ft/s)(sin(44°)). We want to find t for h=0.

  0 = -16t² +65sin(44°) +4

Dividing by -16 gives ...

  0 = t^2 -2.82205t -0.2500

Using the quadratic formula, we find ...

  t ≈ (2.82205 ±√(2.82205² -4(1)(-0.25))/2 ≈ 1.41103 +√2.24099

  t ≈ 2.90802

It will take about 2.908 seconds for the discus to reach the ground.

_____

Comment on the question

You're apparently supposed to use the equation for ballistic motion even though we know a discus has a shape that allows it to "fly". It doesn't drop like a rock would.

the first one, all those points on the line just make a strait line.

x/3-10=8

x/3=18

x=48