Projectile problem w/ unkown velocity/time

  • Thread starter Thread starter bmyer
  • Start date Start date
  • Tags Tags
    Projectile
AI Thread Summary
An athlete's long jump problem involves calculating the take-off speed given a launch angle of 25° and a landing distance of 6.30 m. The relevant equations include components of projectile motion, specifically relating horizontal distance to velocity and time. The solution approach involves breaking down the motion into horizontal and vertical components, using trigonometric relationships to express time in terms of initial velocity. The final calculation leads to a take-off speed of approximately 8.98 m/s. Understanding these principles is crucial for mastering projectile motion in physics.
bmyer
Messages
2
Reaction score
0

Homework Statement


An athlete executing a long jump leaves the ground at a 25° angle and lands 6.30 m away.
What was his take off speed?

Homework Equations


(In all equations, X can be substituted for Y in entire equation)
Vy= Voy + AyT
Vy^2 = Voy + 2AyY
Y=VoyT + (1/2)AyT^2

The Attempt at a Solution


The answer is 8.98 m/s. I can't figure out how to do this problem, and need to understand this for an upcoming final. I have worked several other similar problems, but none without a known velocity and/or time.
Any insight into how to even begin would be greatly appreciated.
 
Last edited:
Physics news on Phys.org
Sorry I edited this because I think i made a mistake don't worry I didn't give up on you.

I'm sorry again I keep getting an answer very close and is probably just off because of my rounding. Though it's been a while since I have done projectile motion and I would hate to show you the wrong way with a final coming up.
 
Last edited:
The x component of velocity is Vo*Cosθ

His total distance would be given by Vo*Cosθ*t

So ...

X = 6.3m = Vo*Cos25*t

Now you still need time so ... look to the skies.

Vo*Sinθ = g*t and t to max height = Vo*Sinθ/g

But total time = 2*t

Now we can solve. t = 2*Vo*Sin25/g = 6.3/Vo*Cos25

Rearranging Vo2*2*Sin25*Cos25 = 6.3*g

Recognizing that 2*Sinθ*Cosθ = Sin2θ

Vo2 = 6.3*g/Sin50
 

Thread 'Struggling to understand the concept of this question (ice cube in water optics question)'

TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
View full post »
Thread 'Variable mass system : water sprayed into a moving container'

Thread 'Variable mass system : water sprayed into a moving container'

Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
View full post »

Similar threads

Projectile Motion Problem Involving Initial Velocity and Gravity Only
Replies
11
Views
1K
Uniform Circular Motion and Projectile Motion Help
Replies
14
Views
2K
What is the total distance traveled by a bullet fragment after an explosion?
Replies
13
Views
2K
Velocity Formulas for Projectile Motion
Replies
10
Views
3K
Supposedly easy physics problem =( [projectile]
Replies
44
Views
5K
Projectile Motion: Finding the Maximum Height of a Football
Replies
5
Views
6K
Projectile Motion velocity vector Problem
Replies
2
Views
2K
Projectile Problem: Find y, vy0, vy Impact, & Velocity Mag/Dir
Replies
1
Views
1K
Is the y-component of projectile motion acceleration equal to gravity?
Replies
8
Views
2K
Projectile motion related problem
Replies
3
Views
3K

Hot Threads

Recent Insights

Back
Top