Question

A projectile is shot from the edge of a cliff h = 145 m above ground level with an initial speed of v0 = 135 m/s at an angle of 37.0° with the horizontal, as shown in Fig. 3-39.

(a) Determine the time taken by the projectile to hit point P at ground level.


- s
(b) Determine the range X of the projectile as measured from the base of the cliff.
- km
(c) At the instant just before the projectile hits point P, find the horizontal and the vertical components of its velocity (take up and to the right as positive directions).
- m/s (horizontal component)
- m/s (vertical component)

Answer 1

resolve vertical and horizontal forces

Answer 2

\[v_{0_{x}}=v _{0}\cos \theta _{0}=135\cos(37.0^{o})= 107.82\]

Answer 3

\[v _{0 _{y}}=v _{0}\sin \theta _{0}= 135\sin(37.0)=81.23\]

Answer 4

^_^

Answer 5

a. time to hit the ground

Answer 6

\[t=2v _{0_{y}}/g\]

Answer 7

\[therfore , t=2(81.23)/9.81=16.6s \]

Answer 8

b. The range X

Answer 9

\[R=v^2\div g * \sin(2\theta) = (107.82)^2/9.81 * \sin(2(37) = 1139m\]

Answer 10

hence, 1.2km

Answer 11

c. the horizontal and vertical components

Answer 12

c. v\[v _{0_{x}}=107.82ms ^{-1}, v _{0_{y}}=81.23ms ^{-1}\]

Answer 13

Take a look at this problem. It is similar and I present all the relevant equations used in projectile motion towards the end. http://openstudy.com/#/updates/4efa9261e4b01ad20b51d179

Answer 14

I believe the values found by @EarthCitizen may not be correct. Look at the work presented by @eashmore or look here for similar examples (including ability to feed in your data and get the results you want): http://hyperphysics.phy-astr.gsu.edu/hbase/traj.html