# Projectile Motion Question #2 help?

• J89
In summary, the challenge involves tossing a quarter with a velocity of 6.4 m/s at an angle of 60 degrees above the horizontal, in order to land it in a dish located on a shelf 2.1 m away from the point where the quarter leaves your hand. While the height of the shelf can be calculated using the equations x=(V0cosa0)t and y=(V0sina0)t - 1/2gt^2, the vertical component of the velocity of the quarter just before it lands in the dish can be found using Vy=V0sina0-gt. However, for accurate results, it is important to use at least 3 digits in calculations, as rounding to 2
J89

## Homework Statement

In a carnival booth, you win a stuffed giraffe if you toss a quarter over a small dish. The dish is on a shelf above the point where the quarter leaves your hand and is a horizontal distance of 2.1 m from this point. If you toss the coin with a velocity of 6.4 m/s at an angle of 60 degrees above the horizontal, the coin lands in the dish. You can ignore air resistance.

a) What is the height of the shelf above the point where the quarter leaves your hand?
b) What is the vertical component of the velocity of the quarter just before it lands the dish?

## Homework Equations

x=(V0cosa0)t
y=(V0sina0)t - 1/2gt^2
Vx=V0cosa0
Vy=V0sina0-gt

## The Attempt at a Solution

I figured part A and the answer is 1.5 m, but for Part B I got -0.93 m/s when I attempted, but the actual answer is -0.89 m/s. I used Vy=V0sina0-gt, where t is .66 s which you get from doing Part A. Help!

Rounding t to .66 is inadequate. If you wish to have 2 digit accuracy in the final answer you need at least 3 digits in calculations.

Oh, I get -0.895 m/s which I would round to .90 so I disagree with the -.89, too!

I would first note that the equations used in the attempt at solving this problem are correct. However, there may have been a mistake in the calculations that led to the incorrect answer. It is important to double check all calculations and make sure the correct values are being plugged into the equations.

Additionally, it would be helpful to draw a diagram of the situation to better visualize the problem and understand the components of the velocity. The vertical component of velocity can also be calculated using the formula Vy=V0sina0, which in this case would give a value of -0.89 m/s.

It is also important to note that the answer may vary slightly due to rounding errors, so the difference between the attempted answer and the actual answer may not be significant. It is always good practice to include units in calculations to avoid errors and ensure accuracy.

In conclusion, double checking calculations and using a diagram to visualize the problem can help in solving projectile motion problems accurately.

## 1. What is projectile motion?

Projectile motion is the motion of an object through the air under the force of gravity. It follows a curved path called a parabola.

## 2. What factors affect projectile motion?

The factors that affect projectile motion include the initial velocity, angle of launch, air resistance, and the force of gravity. These factors can change the distance, height, and time of flight of the projectile.

## 3. How is the range of a projectile calculated?

The range of a projectile can be calculated using the formula: R = (v² * sin(2θ)) / g, where R is the range, v is the initial velocity, θ is the angle of launch, and g is the acceleration due to gravity.

## 4. Is projectile motion affected by air resistance?

Yes, air resistance can affect the trajectory of a projectile by slowing it down and altering its path. However, this effect is usually small and can be ignored in most cases.

## 5. How is projectile motion used in real life?

Projectile motion is used in various real-life applications such as sports (e.g. throwing a baseball or shooting a basketball), launching objects into space, and calculating the trajectory of a bullet. It is also used in physics experiments and simulations to study the effects of gravity and air resistance on moving objects.

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