Question

need help on all parts

Due Date: 21112019 11:59:00 PM End Date: 12/30/2019 12:00:00 AM (10%) Problem 9: A block falls from rest off a building that is y = 188 m tall. A 25% Part (a) At what time in seconds, does the block hit the ground? A 25% Part (b) How long, in seconds, does it take for the block to be y'= 48 m off the ground? A 25% Part (C) How much time, in seconds, does it take for the block to fall the additional y'distance? 25% Part (d) What is the speed, in meters per second, of the block right before it hits the ground? v=1 cos() tano 7 8 9 HOME

Answer 1

here,

the initial height of ball , y1 = 188 m

a)

let the time taken by ball to hit the ground be t1

using second equation of motion

y1 = 0 + 0.5 * g * t1^2

188 = 0 + 0.5 * 9.81 * t1^2

t1 = 6.2 s

the time taken is 6.2 s

b)

y2 = 48 m

let the time taken by ball to reach y2 be t2

using second equation of motion

y1 - y2 = 0 + 0.5 * g * t2^2

188 - 48 = 0 + 0.5 * 9.81 * t2^2

t2 = 5.34 s

the time taken is 5.34 s

c)

the additional time taken , t3 = t1 - t2

t3 = 6.2 - 5.34 s = 0.86 s

d)

the speed when it hits the ground , v = 0 + g * t1

v = 9.81 * 6.2 m/s = 60.8 m/s