# Projectile motion (1 question)

1. Feb 17, 2006

### rachael

A stone is prjected with a velocity of 100m/s at an elevation of 30 degrees form a tower 150m high. Find:
a. the time of flight
ans:12.(4) secs
b. the horizontal distance from the tower at which the stone strikes the ground
ans: 1.0(8) x 10 3
c. the magnitude and the direction of the velocity of the stone striking the ground.
Ans: 114m/s at 40(5) degrees below horizontal

THANKS

2. Feb 17, 2006

### finchie_88

1. $$y = 30tsin30 - 4.9t^2 + 150$$
solve that, when y = 0.
2. $$x = 30tcos30$$ use the value for t that you just worked out.
3. $$v_y = 30sin30 - 9.8t$$
$$v_x = 30cos30$$
Solve these two, using the value of t you got in part 1, and then use pythagoras