You throw a glob of putty straight up toward the ceiling, which is 3.60m above t

Question

You throw a glob of putty straight up toward the ceiling, which is 3.60m above the point where the putty leaves your hand. The initial speed of the putty is 9.50m/s. (i) What is the speed of the putty just before it strikes the ceiling? (ii) How much time when it leaves your hand docs it take the putty to reach the ceiling? A jet fighter wishes to accelerate at 5.9 (g=9.8m/s^2) to escape a dogfight as quickly as possible. Experimental evidence shows that this acceleratignjwill black out the pilot if it lasts for longer than 5.0s. (i) What is the greatest speed the pilot can reach before blacking out? (ii) How far will the pilot travel? A basketball player jumping towards the basket seems to 'hang' in the air. Even the best athletes spend at most 1.00s in the air. Let y_nuix be the maximum height of the athlete off the ground. To see why they appear to hang in the air, calculate the ratio of the time he is above y_max/2 to the total time the athlete is off the ground. Ignore air resistance. Explain your answer.

Explanation / Answer

a)
i)
vi = 9.5 m/s
a = -9.8 m/s^2
d = 3.6 m

use:
vf^2 = vi^2 + 2*a*d
=9.5^2 + 2*(-9.8)*3.6
= 90.25 - 70.56
=19.69
vf = 4.44 m/s
Answer: 4.44 m/s

ii)
vf = vi + a*t
4.44 =9.5 - 9.8*t
t=0.52 s

b)
vi = 0 m/s
a = 5*g = 5*9.8 = 49 m/s^2
t = 5s
i)
vf = vi + a*t
= 0 + 49*5
= 245 m/s
Answer: 245 m/s
ii)
d = vi*t + 0.5*a*t^2
= 0 + 0.5*49*5^2
= 612.5 m
Answer: 612.5 m

We are allowed to answer only 4 parts at a time.

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