Homework Help: physics

Posted by qwertzuiop on Saturday, January 28, 2012 at 7:56pm.

Marie shoots an arrow vertically upward at a sandhill crane. If the arrow travels to a maximum height of 99.5 meters, calculate how fast it was shot.
And, for how much time was Marie's arrow in the air?

physics - Damon, Saturday, January 28, 2012 at 8:36pm
v = Vi - 9.8 t
0 = Vi - 9.8 t
Vi = 9.8 t

99.5 = Vi t -4.9 t^2
99.5 = 9.8 t^2 - 4.9 t^2 = 4.9 t^2
t = 4.5 seconds to top
so
Vi = 9.8 * 4.5 = 44.2 m/s

You could also do this by conservation of energy
(1/2) m Vi^2 = m g h
so
Vi = sqrt (2*9.8*99.5)
= 44.2 m/s

Answer this Question

Related Questions

physics - Marie shoots an arrow vertically upward at a sandhill crane (she ...
physics - Marie shoots an arrow vertically upward at a sandhill crane. If the ...
Physics (Mechanics) - Marie shoots an arrow vertically upward at a sandhill ...
physics - An arrow is short vertically upward with an initial speed of 25m/s. ...
Physics 11 - Mark Ji shoots a 40gram arrow straight up in the air at 30m/s ...
physics - An arrow is shot from the top of a building (height of 30 meters). The...
Physics - An archer shoots an arrow that leaves the bow at an angle of 42 ...
Physics - An archer shoots an arrow that leaves the bow at an angle of 42 ...
Physics - An arrow is shot from the top of a building (height of 30 meters). The...
physics - An archer shoots an arrow horizontally with an initial velocity of 100...

For Further Reading

First Name:
School Subject:
Answer: