A water bottle is shot upward with an initial velocity of 45 feet per second from a roof 18 feet high. Create an equation to model this.

Answer 1

y=18+45x

Since 18' is constant (always starting position of water bottle), the end units will be in feet (y=position). The 45 ft/s should be multiplied by X-seconds to obtain feet. Also, the (+) and NOT (-) is because the water bottle is shot upward (assume up is positive). So position equals original position plus speed/rate multiplied by time/seconds. For example, at 0 seconds, the water bottle doesn't move, hence 18' is its position. At 2 seconds, 18+45(2)=108, the water bottle will have traveled 90' plus the original 18' so 108' is the position at 2 seconds.