Durable apparatus to study velocity, acceleration, and projectile motion. Marbles can be launched from five different speeds at any angle between 0 and 90?. Velocity of the marble can range from 3 m/s to 9 m/s. Easy-to-read protractor allows for precise measurements and calculations. Sturdy hardwood construction is built to last. Includes a detailed instruction guide and two marbles. 16 L x 10 W x 12 H.