Another question about projectile motion

In summary, a stunt man jumps from one building to another building 4.9m away, with an angle of 16 degrees and a speed of 5.1 m/s. The second building is 1.9m shorter than the first building. To find his vertical displacement upon reaching the front edge of the lower building with respect to the taller building, you can use the initial velocity's x and y components. The 1.9m difference in building height is relevant to this problem.
  • #1
physics=headache
A stunt man jumps from the top of one building to the top of another building 4.9 m away. after a running start, he leaps at an angle of 16 degrees with respect to the flat roof while traveling at a speed of 5.1 m/s. the other roof is 1.9 shorter than the building from which he jumped. i have to find out his vertical displacement upon reaching the front edge of the lower building with respect to the taller building.

heres my thoughts on what to do: i can use 16 degrees and 5.1 m/s to find the x and y component of the initial velocity. that's all I've got so far.

any help would be appreciated
 
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  • #2
i can use 16 degrees and 5.1 m/s to find the x and y component of the initial velocity
Right. So what's the problem? Once you've done that, how long does it take him to travel 4.9m horizontally? Then, given his initial VERTICAL velocity, what is his vertical displacement after that length of time?
 
  • #3
still can't get it

ok i got that, but where does the 1.9 m come in?
 
  • #4
Presumably it's there to help you learn to distinguish between relevant and extraneous information. :smile:
 
  • #5
Originally posted by gnome
Right. So what's the problem? Once you've done that, how long does it take him to travel 4.9m horizontally? Then, given his initial VERTICAL velocity, what is his vertical displacement after that length of time?

y(t) = -9.81*t^2 + Voy*t + 1.9m

The jumpers initial height is 1.9m.
 
  • #6
Nope,

the height you need to find is with respect to the taller building.

The 1.9m is there because either:

1) The jump isn't enough to clear the gap.

or

2) It's there to trip you up with extraneous information.
 
  • #7
Presumably it's there to help you learn to distinguish between relevant and extraneous information.
When I fire from the hip, I tend to shoot myself in the foot.

Working out the actual numbers, it seems that when he reaches the second building, his vertical displacement
is -3.49m; i.e. his feet hit the wall 1.59m (3.49-1.9) below the roof. That's where the 1.9m height difference comes in.
 
  • #8
you could find the solution in the Haliday and Resnick book (plane motion). It is solved there.

hhegab
 

1. What is projectile motion?

Projectile motion refers to the curved path that an object takes when it is thrown or launched into the air. It is a combination of horizontal and vertical motion due to the force of gravity.

2. What factors affect projectile motion?

The factors that affect projectile motion include the initial velocity, the angle of projection, and the force of gravity. Air resistance and wind can also have an impact on the path of the projectile.

3. How does the angle of projection affect projectile motion?

The angle of projection determines the height and distance that the projectile will travel. A higher angle will result in a longer flight time and a higher peak height, while a lower angle will result in a shorter flight time and a lower peak height.

4. What is the difference between horizontal and vertical motion in projectile motion?

Horizontal motion refers to the movement of the projectile along the x-axis, while vertical motion refers to the movement along the y-axis. In projectile motion, the horizontal velocity remains constant, while the vertical velocity is affected by the force of gravity.

5. How can projectile motion be calculated?

Projectile motion can be calculated using the equations of motion, which take into account the initial velocity, angle of projection, and time. These equations can be solved for variables such as time, distance, and velocity to determine the path of the projectile.

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