Worksheet Freefall #3 (Honors)

Refer to the following information for the next three questions.

While holding his rifle at shoulder-level, a 1.8 meter-tall hunter accidentally discharges it straight up into the air.
 If the bullet exits the barrel of the rifle at 200 m/sec how many seconds does the hunter have to "step aside" to avoid being hit by the descending bullet?

 How high did the bullet rise in the air before it starting falling back down to earth?

 If he does not move fast enough, at what velocity would the descending bullet strike his shoulder?

Refer to the following information for the next two questions.

When rising to spike a ball in a volleyball game, a player jumps vertically 1.5 meters off the floor.
 How much total time does he spend in the air, assuming he lands in the same position from which he left the ground.

 At what velocity did he hit the ground at the end of the jump?

Refer to the following information for the next three questions.

Two students are tossing a set of keys from one to the other. The first student (who initially has the keys) is 1.8 meters tall and is standing on the ground 4 meters below the second student who is on a catwalk.

The student on the ground tosses the keys upward, releasing them exactly as his hand reaches the top of his head, with just the right velocity so that their apex coincides with the second student's outreached hand.
Which kinematics variables are stated in this problem?
 How fast were the keys tossed?

 How much time did the keys spend in the air?

Refer to the following information for the next three questions.

Suppose that the student on the balcony was distracted and failed to catch the keys and they fall back down to the ground.
 With what velocity will they strike the grass at the feet of the first student?

True or False. The keys spent the same amount of time falling to the ground as they spent rising towards the balcony.
True or False. The keys struck the ground at the same speed as they were originally tossed upwards by the first student.
Refer to the following information for the next four questions.

Three students are standing side-by-side next to the railing on a fifth floor balcony. Simultaneously, the three students release their pennies.
• One student proceeds to drop a penny to the ground below.
• The second student tosses his penny straight downwards at 15 m/sec, while
• The third student tosses his penny straight upwards at 15 m/sec.

Which penny or pennies strike(s) the ground first?

Which penny or pennies strike(s) the ground last?

Which penny or pennies strike(s) the ground with the greatest final velocity?

 As the pennies are falling, a person on the 3rd floor times one of the pennies as it passes her 1.5-meter tall bedroom window. If the penny took 0.15 seconds to clear her window, how fast was the penny traveling just as it entered the top of her window frame?

Refer to the following information for the next five questions.

A student, while packing up his book bag that islocated near the edge of a lab table 95-cm tall, accidentally drops his pencil on the floor.
Which kinematics variables are stated in this problem?
 With what velocity with the pencil hit the floor?

 How much time does it take the pencil to fall and strike the floor?

 If the room temperature is 25 ºC, how much total time passed between when he lost his grip on the pencil and when he hears the sound of it hitting the floor?

 Modeling this situation, how deep is a well if the sound of a penny striking the water is heard 4 seconds after the penny is released? You may assume that the temperature remains 25 ºC.