Patrick D. answered • 04/25/17

Tutor

5
(10)
Patrick the Math Doctor

We need to know how fast he was falling at the instant he pulled the cord.

That is initial velocity.

acceleration = final velocity - initial velocity

-------------------------------------

time

10 = ( final velocity - initial velocity)/4

40 = final velocity - initial velocity

40 + initial velocity = final velocity

When you find that number add it to 40 to get your answer.

We can also get the answer if we know how far he fell during the 4 seconds

between the time he pulled the cord to when the parachute opens.