1644519293 184 PHYS 100 - Tutorial 4 2022 - solution.pdf -...

Tutorial 4
February 8-10, 2022
Question 1 – A golfer hits a shot to a green that is elevated 3 m above the point where the ball
is struck. The ball leaves the club with a speed of 14.0 m/s at an angle of 40° above the
horizontal. The ball rises to its maximum height and then falls to the green. Find the speed of
the ball just before it lands. (Do you expect this to be greater than, less than, or equal to the
initial speed?)
We want final speed. We know total displacement in the y is +3.0 m. We know horizontal
speed will stay constant if we ignore air resistance. We know acceleration in the y
direction is g. We need to stick a minus sign in since the initial y velocity is up or positive,
and the final is down so we will call it negative. So, we find the final x and y components
of velocity and then add them as perpendicular vectors using Pythagorean theorem.
Horizontally, we get
For the vertical we do not know time, but we know y, so we use equation

So final speed is gotten from