(8%) Problem 1: When you dop an object, it accelerates downward at 32.2 fis2. à

Question

(8%) Problem 1: When you dop an object, it accelerates downward at 32.2 fis2. à Consider what happens if a ball is thrown upward at an angle above the horizon. What is the acceleration, in ft/s?, in the vertical direction as it falls back down at an angle? Cannot determine unless both the speed and angle of the throw are known. Grade Summary Deductions 0% 32.2 ft/s Less than 32.2 ft/s2 Greater than 32.2 ft/s2 Cannot determine unless the angle of the throw is known. Cannot determine unless the speed of the throw is known Submissions Attempts remaining: 5 (20% per attempt) detailed view Submit Hint Hints: 0% deduction per hint. Hints rem aining:-1 Feedback: 0%-deduction per feedback.

Explanation / Answer

1.

When a ball is thrown at some angle from horizon, In the vertical direction there will be only gravitational force which will attract the ball downward, So acceleration of ball in vertical direction will always be equal to gravitational acceleration.

Which is g = 32.2 ft/sec^2

Correct option is B.

2A.

Since ball is dropped, So Vi = 0 m/sec

2B.

from Q1 when ball is dropped there is only gravitational acceleration which will be downward

g = -32.2 ft/sec^2 = -9.81 m/sec^2

Since we need magnitude in SI unit, So

|a| = 9.81 m/sec^2

2C.

Vf = Vi + a*dt

Vf = 0 - (9.81 m/sec^2)*3.2 sec

Vf = -31.39

Magnitude will be

|Vf| = 31.39 m/sec

2E.

dy = Vi*dt + 0.5*a*dt^2

2F.

dy = 0*3.2 + 0.5*(-9.81)*3.2^2

dy = -50.23 m

Magnitude will be

dy = 50.23 m = height of buliding

4A.

a = g, initial velocity = V0, final velocity = Vf

We know that

Vf = V0 + g*t

Vf^2 = V0^2 + 2*g*h

from above equation

Vf = sqrt (V0^2 + 2*g*h)

Use this value of Vf in 1st equation

Vf = V0 + g*t

t = (Vf - V0)/g

t = (sqrt (V0^2 + 2gh) - V0)/g

Correct option is C. (3rd one in upper options)

4B.

Using given values

h = 324 m

V0 = 12 m/sec

g = 9.81 m/sec^2

So,

t = [sqrt (12^2 + 2*9.81*324) - 12]/9.81

t = 6.9957 = 7.00 sec

4C.

We know that

Vf = sqrt (V0^2 + 2gh)

So,

Vf = sqrt (12^2 + 2*9.81*324)

Vf = 80.63 m/sec

Please Upvote.

Comment below if you have any doubt in solved parts.

Ask rest of the questions as a new question, I have already answered 3 different questions.

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