aon th rof of s 4 m all bulding and deows a rock with a vlocth of magltad 40 m\'
ID: 1773670 • Letter: A
Question
aon th rof of s 4 m all bulding and deows a rock with a vlocth of magltad 40 m's an anglk ofs ne the horizontal. (a) What are the horizontal and the vertical components of the initial velocity briontal ed the verialcmpnents of th niial 30 m Is 25 H- 45m (b) What are the velocity and acceleration when the rock is at its highest point. (e) Find the time taken by the rock to reach the highest polint and its height at the highest point. (d) How long does it tuke the rock to hit the ground after launch and how far from the starting point it hits the ground. (e) Calculate the velocity (magnitude and the angle) of the rock just before it sarikes the ground.Explanation / Answer
(a) ux = 36.3 m/s
uy = 16.9 m/s
----------------------------------------------------------------------------------------------------------
(b) At the highest point,
vx = ux = 36.3 m/s
vy = 0
Therefore, velocity at highest point is 36.3 m/s
------------------------------------------------------------------------------------------------------
(c)
vy = uy + gt
=> 0 = 16.9 + (-9.81)(t)
=> t = 1.72 s
sy = uyt + (1/2)gt2
=> sy = (16.9)(1.72) +(1/2)(-9.81)(1.72)2
=> sy = 14.6 m
Height from ground = 14.6 + 45 = 59.6 m
Therefore, the highest point is 59.6 m above the ground
---------------------------------------------------------------------------------------------------------
(d) When the rock hits the ground,
sy = -45 m
-45 = (16.9)(t) + (1/2)gt2
=> -45 = (16.9)(t) + (1/2)(-9.81)t2
=> 4.9t2 - 16.9t - 45 = 0
=> t = 5.21 s
sx = uxt
=> sx= (36.3)(5.21) = 189.12 m
-----------------------------------------------------------------------------------------------------------------
(e) when the rock hits the ground,
vx = 36.3 m/s
vy = uy + gt
=> vy = 16.9 + (-9.81)(5.21)
=> vy = -34.21 m/s
= Tan-1(vy/vx)
=> = -43.30
----------------------------------------------------------------------------------------------------------
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.