Rock Thrown from 32m Building: Vertical Velocity at 6m Question

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In summary, the conversation was about a rock being thrown off a 32 m high building with a horizontal velocity of 5 m/s. The question asked for the vertical velocity when the rock reaches 6 m from the ground, using g = 10 m/s^2. The options for the answer were 11 m/s, 120 m/s, 23 m/s, 520 m/s, and 16 m/s. The student thought the correct answer was 23 m/s, but did not show any work.
  • #1
Jud Rice
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Homework Statement


A rock is thrown off of a 32 m high building with a horizontal velocity of 5 m/s. What is the vertical velocity when it reaches 6 m from the ground? Use g = 10 m/s^2

A) 11 m/s
B) 120 m/s
C) 23 m/s
D) 520 m/s
E) 16 m/s

Homework Equations


Kinematics I think

The Attempt at a Solution


I think it is 23 m/s but not sure
 
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  • #2
Jud Rice said:

Homework Statement


A rock is thrown off of a 32 m high building with a horizontal velocity of 5 m/s. What is the vertical velocity when it reaches 6 m from the ground? Use g = 10 m/s^2

A) 11 m/s
B) 120 m/s
C) 23 m/s
D) 520 m/s
E) 16 m/s

Homework Equations


Kinematics I think

The Attempt at a Solution


I think it is 23 m/s but not sure
Please show your work.
 
  • #3
berkeman said:
Please show your work.
No.
 
  • #4
Whelp, then maybe a 10-day vacation from the very helpful PF will adjust your attitude. We require that students show effort on their schoolwork here.
 
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  • #5
He created a sockpuppet to try to get around his temp ban, so he's not coming back. Unbelievable bad attitude.
 
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1. How do you calculate the vertical velocity of a rock thrown from a 32m building at a height of 6m?

The vertical velocity of a projectile can be calculated using the equation v = u + at, where v is the final velocity, u is the initial velocity (in this case, 0 m/s), a is the acceleration due to gravity (-9.8 m/s^2), and t is the time the rock takes to reach the ground. In this scenario, the rock will take approximately 1.6 seconds to reach the ground, and therefore, the vertical velocity will be -15.68 m/s.

2. How does the height of the building affect the vertical velocity of the rock?

The height of the building does not affect the vertical velocity of the rock, as long as the initial height (32m) and the final height (6m) are constant. The only factors that affect the vertical velocity are the acceleration due to gravity and the time it takes for the rock to reach the ground.

3. Why is the initial velocity of the rock considered to be 0 m/s?

The initial velocity of the rock is considered to be 0 m/s because it is thrown from a stationary position (i.e. it is not already moving at the time of release). In other words, the rock starts with no initial velocity, and the only force acting on it is the force of gravity.

4. Can the vertical velocity of the rock be positive?

Yes, the vertical velocity of the rock can be positive if it is thrown upwards with enough initial velocity to overcome the acceleration due to gravity. However, in this scenario, the rock is thrown downwards, and therefore, the vertical velocity is negative.

5. How accurate is this calculation of the vertical velocity?

This calculation is relatively accurate, assuming that the initial height, final height, and acceleration due to gravity are all constant. However, it is important to note that factors such as air resistance and variations in the acceleration due to gravity (due to location or altitude) may affect the accuracy of the calculation.

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