# Speed, Angle, Distance Homework HELP

## Homework Statement

After a golf ball is hit it takes off with an initial speed of 20.9 m/s and at an angle of 43.5° with respect to the horizontal. The golf field is flat and horizontal.

Neglecting air resistance how far will the golf ball fly?

How high will the golf ball rise?

How far would the ball fly if the initial speed was doubled?

How much time would the ball spend in the air in this second case?

## Homework Equations

Professor posted this,

Once the ball leaves the shooter's hand it is in free-fall. Objects in free-fall have constant acceleration of 9.81 m/s2 DOWNWARD at all times while they are in free-fall. In addition, they have CONSTANT velocity in the horizontal direction (remember, constant velocity means acceleration in this direction is zero). Therefore, the larger the magnitude of the vertical component of the velocity, the higher the speed.

Also, speed and velocity are not synonymous. Speed (a scalar) is the magnitude of the velocity vector. Speed only has a magnitude/size, it has no direction and cannot be negative. Velocity has both a magnitude AND a direction. When references are made to the vertical component of the velocity vector in this problem, upwards is defined as the positive y direction; therefore 10 m/s upward is greater than 10 m/s downward (but the speeds associated with these two vertical velocities are equal)!

## The Attempt at a Solution

Having trouble and don't know what to do.