Homework Clinic
Science Clinic => Physics => Topic started by: Millan on Jun 22, 2013
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Need help on homework; I can't find the answer anywhere. Please help!
If the y component of the initial velocity for a projectile is 10m/s, how long will the projectile stay in the air before coming back to the original level?
A.) 10s
B.) 20s
C.) 2s
D.) 1s
Thank you!
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Answer C
When the projectile reaches the maximal height Vy = 0
Vy = V°y - gt if Vy = 0 ---- V°y = g t and t = V°y /g = 10 / 9.8 = 1.02041 s
Y = V°y t - 1/2 g t^2 --- 10 * 1.02041 - 0.5 * 9.8 * 1.04123= 10.2041 - 5.10204 = 5.1020 m
The duration of the free fall is identical in the time of rise = 1.02041
Time total = 1.02041 * 2 = 2.0408 s
Goodbye