Homework Help: Physics

Posted by Krystal on Sunday, February 5, 2012 at 12:58pm.

A projectile is fired from ground level with a speed of 40 m/s at an angle of 30 degrees and hits a building 100m away.
What is the time of flight of the projectile?
How high above ground does the projectile hit the building?
What is the speed of the projectile just before it strikes the building?

Physics - Henry, Tuesday, February 7, 2012 at 7:20am
Vo = 40 m/s @ 30 Deg.
Xo = 40*cos30 = 34.6 m/s.
Yo = 40*sin30 = 20 m/s.

a. Tr = (Yf-Yo)/g,
Tr = (0-20) / -9.8 = 2.04 s. = Time to
rise to max ht.
Tf = Tr = 2.04 s. = Fall time.
Tr + Tf = 2.04 + 2.04 = 4.08 s. = Time of flight.

b. hmax = Yo*t + 0.5g*t^2,
hmax = 20*2.04 - 4.9(2.04)^2=20.4 m.

Yf = Yo + gt,
Yf = 0 + 9.8*2.04 = 20 m/s.= Final velocity before striking gnd.

Answer this Question

Related Questions

physics - a projectile is fired from the surface of the earth with a speed of ...
PHYSICS - A projectile is fired from the surface of the Earth with a speed of ...
AP PYHSICS - A projectile is fired from the surface of the Earth with a speed of...
physics - if a ball, fired as a projectile, travels 30 meters when it leaves the...
physics - if a ball, fired as a projectile, travels 30 meters when it leaves the...
Physics - A projectile is fired with an initial speed of 28.0 m/s at an angle of...
Physics - In the absence of air resistance, a projectile is launched from and ...
college physics - a toy cannon fires a projectile from ground level with a speed...
physics - A projectile is fired at an upward angle of 45 degrees from the top of...
College Physics - A projectile is fired at an upward angle of 55.0 degrees from ...

For Further Reading

First Name:
School Subject:
Answer: