How to Derive Initial Velocity in Projectile Motion Using Lab Measurements?

In summary, the conversation is about deriving a formula for calculating the initial velocity of a ball released from a turntable using only measurable quantities from an angular momentum lab. The formula is v=d(g/2h)^{1/2}. The participants discuss using motion with constant acceleration and knowing the ball's vertical and horizontal distances to calculate the time it took to fall and the distance it traveled horizontally.
  • #1
J_o_S
18
0
Hi

I'm having trouble figuring this one out..based on an angular momentum lab.

In the lab we had a turntable with a ball on it, when the ball was released, the intial velocity could be calculated using the formula


[itex]v=d(g/2h)^{1/2}[/itex]

I need to be able to derive the same formula

[itex]v=d(g/2h)^{1/2}[/itex]

using only measureable quantites from my lab.

measure quantities are

height (ball to table top)
mass of the ball
distance between axis of rotation and ball
distance horizontal distance

I have to derive this equation using horizontal and vertical coordinates.

any ideas?
 
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  • #2
J_o_S said:
Hi

I'm having trouble figuring this one out..based on an angular momentum lab.

In the lab we had a turntable with a ball on it, when the ball was released, the intial velocity could be calculated using the formula


[itex]v=d(g/2h)^{1/2}[/itex]

I need to be able to derive the same formula

[itex]v=d(g/2h)^{1/2}[/itex]

using only measureable quantites from my lab.

measure quantities are

height (ball to table top)
mass of the ball
distance between axis of rotation and ball
distance horizontal distance

I have to derive this equation using horizontal and vertical coordinates.

any ideas?

Well, it's motion with constant acceleration. You know how far it fell (vertically) so you should be able to calculate the time it took to fall. Then you know it moved horizontally with constant speed, and you know how far it went and (from the vertical equation) how long it was in the air.

-Dan
 

FAQ: How to Derive Initial Velocity in Projectile Motion Using Lab Measurements?

What is the equation for calculating the horizontal velocity of a projectile?

The equation for calculating the horizontal velocity of a projectile is Vx = V0 * cos(θ), where Vx is the horizontal velocity, V0 is the initial velocity, and θ is the launch angle.

How do you find the vertical distance of a projectile at a certain time?

The equation for calculating the vertical distance of a projectile at a certain time is y = V0 * sin(θ) * t - 1/2 * g * t^2, where y is the vertical distance, V0 is the initial velocity, θ is the launch angle, t is the time, and g is the acceleration due to gravity.

Can you determine the maximum height reached by a projectile using equations?

Yes, the equation for calculating the maximum height reached by a projectile is Hmax = (V0 * sin(θ))^2 / 2g, where Hmax is the maximum height, V0 is the initial velocity, θ is the launch angle, and g is the acceleration due to gravity.

What is the range equation for projectile motion?

The range equation for projectile motion is R = (V0^2 * sin(2θ)) / g, where R is the range, V0 is the initial velocity, θ is the launch angle, and g is the acceleration due to gravity.

How do you account for air resistance in projectile motion equations?

To account for air resistance in projectile motion equations, you can use the drag force equation, Fdrag = 1/2 * ρ * v^2 * Cd * A, where ρ is the air density, v is the velocity, Cd is the drag coefficient, and A is the cross-sectional area. This force can be factored into the equations for horizontal and vertical motion to adjust for the effects of air resistance.

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