# Solving Projectile Motion: A Building 70.0 m High

• ScienceGirl90
In summary: He mentions that his teacher briefly explained projectile motion but he is still confused. The expert suggests using the SUVAT equations to solve the problem and provides step-by-step instructions on how to use them to calculate the fall time, vertical impact speed, and horizontal impact speed. By combining these values, Jared can find the impact speed and angle.
ScienceGirl90

## Homework Statement

A ball is thrown horizontally from the top of a building 70.0 m high. The ball strikes the ground 90.0 m from the base of the building (Neglecting air resistance). How fast and at what angle (relative to horizontal) does the ball strike the ground?

I'm not sure!

## The Attempt at a Solution

You should use the SUVAT equations.

First, calculate the time taking to fall the 70m from the top of the building using s= u*t + 0.5*a*(t^2).

Where s = distance, u = initial speed, v = final speed, a = acceleration and t = time.

(Can you see why they're called SUVAT equations?)

You know u = 0m/s, a = 9.8m/s^2, t = ? and s = 70m. Plug them in and rearrange to get the fall time t.

Then, using v = u + at with the values from above, you can get vertical impact speed v.

Because fall time vertically = flight time horizontally, you now know how long it took to travel the 90m horizontally. Because you are neglecting air resistance, for the horizontal flight u = v and a = 0.

So using s = u*t + 0.5*a*(t^2), where a = 0, s = 90 and t = answer from first section, you can plug in your values and get u = v.

You now have both vertical impact speed and horizontal impact speed. Combine the two using basic trigonometry and you get your impact speed and angle.

Jared

## What is projectile motion?

Projectile motion is the motion of an object that is projected into the air at an angle. It follows a curved path due to the influence of both horizontal and vertical forces.

## What factors affect projectile motion?

The factors that affect projectile motion include the initial velocity, angle of projection, air resistance, and gravity.

## How do you solve projectile motion problems?

To solve projectile motion problems, you can use the equations of motion, which take into account the initial velocity, angle of projection, and acceleration due to gravity. You can also use vector analysis to break down the initial velocity into its horizontal and vertical components.

## What is the equation for finding the maximum height of a projectile?

The equation for finding the maximum height of a projectile is h = (v02 * sin2θ) / 2g, where h is the maximum height, v0 is the initial velocity, θ is the angle of projection, and g is the acceleration due to gravity.

## How do you find the range of a projectile?

To find the range of a projectile, you can use the equation R = (v02 * sin2θ) / g, where R is the range, v0 is the initial velocity, θ is the angle of projection, and g is the acceleration due to gravity. Alternatively, you can use the equation R = (v02 * sinθ * cosθ) / g.

• Introductory Physics Homework Help
Replies
2
Views
924
• Introductory Physics Homework Help
Replies
7
Views
2K
• Introductory Physics Homework Help
Replies
1
Views
1K
• Introductory Physics Homework Help
Replies
11
Views
911
• Introductory Physics Homework Help
Replies
1
Views
1K
• Introductory Physics Homework Help
Replies
3
Views
514
• Introductory Physics Homework Help
Replies
9
Views
1K
• Introductory Physics Homework Help
Replies
3
Views
3K
• Introductory Physics Homework Help
Replies
4
Views
1K
• Introductory Physics Homework Help
Replies
4
Views
899