posted by Maggie on .
1)A fire hose held near the ground shoots water at a speed of6.5 mps
At what angle should the nozzle point in order that the water land 2.5 meters away?
Answers: 18 degrees and 72 degrees
2) A long jumper leaves the ground at 45 degrees above the horizontal and lands 8 meters away.
a)What is her "takeoff" speed?
b) Now she is out on a hike and comes to the left bank of a river. There is no bridge and the right bank is 10 meters away horizontally, and 2.5 meters vertically below. If she jumps from the edge of the left bank at a 45 degree angle with the speed calculated in question a)how long or short from the opposite bank will she land?
Answers: a) 8.9 meters per second
b) short by 0.1 m
3) A baseball is hit with a speed of 27 meters per second at an angle of 45 degrees. It lands on the flat roof of a 13 meter tall building. If the ball was hit when it was 1 meter above the ground, what horizontal distance does it travel before it lands on the building? Answer: 57.8 meters
Range = 2.5 = (Vo^2/g)sin(2A)
where A is the angle from horizontal.
sin(2A) = 9.8*2.5/(6.5)^2 = 0.580
2A = 35.4 or 144.6 degrees
A= 17.7 or 72.3 degrees
Try doing the others yourself; someone will critique your effort.