Projectile Motion: Time and Impact Velocity Comparison - Homework Question

In summary, the conversation discusses the comparison between the time it takes and impact velocity of a ball when it is tossed up and dropped to the ground, and when it is simply allowed to fall. It is mentioned that the heights from which the ball starts falling are different, which means that the time taken should also be different. However, in projectile motion problems with an original vertical velocity, the same answer is obtained without calculating the two separate paths. It is also noted that air resistance is usually ignored in these calculations, which is a good assumption but not entirely accurate. When considering air resistance, the times may be affected differently.
  • #1
phizics09
38
1

Homework Statement



When you toss a ball up and let it drop to the ground, compared to when you just let it fall, will the time it takes to reach the ground and impact velocity be equal?

Homework Equations





The Attempt at a Solution


For the time, they shouldn't be equal, since the height from which the ball starts falling is different right? But how come when you solve projectile motion problems with an original velocity in the vertical direction, you don't need to calculate the separate two paths--one up and one down--separately, but you still get the same answer?
 
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  • #2
An assumption (physics is full of 'good' assumptions) is that air resistance can be ignored.
This is good in the first instance but it is obviously untrue and must be taken into account in a full analysis. But, you have to start some where
 
  • #3
What do you mean?
 
  • #4
Think about the two trajectories. In the case where the ball is thrown straight up, it will eventually reach a highest point at which its height from the ground is h. What is the velocity of the ball at that point? How is the similar or different to the velocity of the ball if you were to simply drop it from that same height?
 
  • #5
If there is no air resistance then there will be no difference at all
 
  • #6
technician said:
If there is no air resistance then there will be no difference at all

Now if you throw in air resistance, and assume the balls are identical, think about what would happen to the times then.
 

FAQ: Projectile Motion: Time and Impact Velocity Comparison - Homework Question

What is projectile motion?

Projectile motion is the motion of an object through the air or space, under the influence of gravity. It follows a curved path known as a parabola.

What factors affect projectile motion?

The factors that affect projectile motion are initial velocity, angle of launch, air resistance, and gravity. These factors determine the trajectory, distance, and time of flight of the projectile.

How do you calculate the range of a projectile?

The range of a projectile can be calculated using the formula R = (V^2 * sin2θ) / 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.

What is the difference between horizontal and vertical components of projectile motion?

The horizontal component of projectile motion refers to the motion in the x-direction, while the vertical component refers to the motion in the y-direction. The horizontal component remains constant, while the vertical component is affected by gravity.

How does projectile motion apply to real-life situations?

Projectile motion can be seen in many real-life situations, such as throwing a ball, shooting a basketball, or launching a rocket. It is also used in sports, engineering, and physics to calculate the trajectory and predict the motion of objects.

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