1. The problem statement, all variables and given/known data A catapult (slingshot) is used to fire a ball of mass 0.2kg vertically into the air. The elastic is stretched so that there is a tension of 40N in both 'sides' of the slingshot, ie on the elastic on either side of the mass (I am trying to describe a diagram here, so please bear with me...). The angle between the mass and each side of the elastic is 50 degrees. The mass is drawn back a distance of 0.1m. The question asks me to find how high the ball will travel after being released, assuming the tension in the elastic remains constant. 2. Relevant equations F=ma Equations of motion? Kinetic/potential energy equations? 3. The attempt at a solution I have drawn a right-angled triangle with a side of 0.1m opposite to the hypotenuse. From this I have reasoned that the force used to draw back the mass equals the sum of the vertical components of the two tensions, ie 2 times 40cos(50 degrees). This is therefore the force used to fire the mass. From this I can figure out the vertical acceleration using F=ma. Although I am unsure if I should subtract gravity from F in this calculation. I know that the ball will cease to rise when the vertical acceleration equals the force downwards due to gravity. But I am unsure of how to get this value. Thanks for any help given.