• Support PF! Buy your school textbooks, materials and every day products Here!

Kinematics. cannonball was dropped- how far from the wall does it hit ground?

  • Thread starter aurorabrv
  • Start date
  • #1
4
0

Homework Statement


King Arthur's knights fire a cannon from the top of the castle wall. The cannonball is fired at a speed of 45m/s and an angle of 32degrees . A cannonball that was accidentally dropped hits the moat below in 1.4s .

a) How far from the castle wall does the cannonball hit the ground?

b) What is the ball's maximum height above the ground?


Homework Equations



Unsure what to use.

The Attempt at a Solution



xi = ti = 0
vi = 45 m/s
vix = 45cos32 = 38.16
viy = 45sin32 = 23.85
ax = 0
ay = -9.8 m/s
yf = 0
yi = 1/2 (-9.8m/s^2)(1.4s)^2 = 9.6 m

horizontal v 45cos32 = 38.16
initial v 45sin32 = 23.85

time of fall 2.43 seconds

57.86/9.8 = root of 5.9
= 2.43 + 2.43
= 4.86
= 185.4576m


max height
1/2(9.8) x 2.43^2 = 28.93 m
 

Answers and Replies

Related Threads on Kinematics. cannonball was dropped- how far from the wall does it hit ground?

Replies
2
Views
1K
Replies
2
Views
2K
Replies
3
Views
1K
Replies
1
Views
5K
Replies
1
Views
1K
Replies
25
Views
7K
Replies
8
Views
1K
Replies
2
Views
2K
Top