# 3 Projectile Problems!

1. Sep 25, 2007

### Lorelyn

1. The problem statement, all variables and given/known data

Volcanoes eject rocks at speeds of 100 m/s. Consider a 1250 m high volcano which ejects rocks in all directions. What is the maximum horizontal distance at sea level reached by the rocks?

2. Relevant equations

basic kinematics ones

3. The attempt at a solution

Well; I found the max height using initial and final velocity, and setting a as -g. That didn't help a whole lot though... So then I tried finding the initial velocity in the x-direction using trig (and assumed the angle was 45deg, because that is the best angle?). I got 70.716m/s. Which still didn't help me!
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1. The problem statement, all variables and given/known data

A basketball player throws the ball at a 35.0 deg angle above the horizontal to a hoop which is located a horizontal distance L = 4.80 m from the point of release and at a height h = 0.80 m above it. What is the required speed if the basketball is to reach the hoop?

2. Relevant equations

basic kinematics ones

3. The attempt at a solution

I actually don't know where to start with this one. I tried finding the veolcity for it to have a max. height > 0.8 and then used a triangle and trig to get the initial velocity but that failed...

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1. The problem statement, all variables and given/known data

At the National Physics Laboratory in England a measurement of the gravitational acceleration g was made by throwing a glass ball straight up in an evacuated tube and letting it return, as shown here The time interval between the two passages across the lower level is equal to DTL = 2.47 s. The time interval between the two passages across the upper level is equal to DTH = 1.20 s. The distance between the two levels is equal to H = 5.42 m. Calculate the magnitude of g.

2. Relevant equations

basic kinematics ones

3. The attempt at a solution

Well I know that in theory g should equal 9.8m/s^2. However to get that number I am very lost.

Last edited: Sep 25, 2007
2. Sep 25, 2007

### Astronuc

Staff Emeritus