In this experiment the impulse on a cart is determined in two ways, by measuring the change in velocity and by finding the area under a force versus time curve.
A Smart Cart runs down a slightly inclined track with its Force Sensor equipped with either a clay bumper, spring bumper or magnetic bumper before colliding with an endstop. To determine the change in momentum (impulse), the speeds before and after the collision are recorded using the Smart Cart’s encoder. To confirm the impulse, the force versus time is plotted and the impulse is determined by finding the area under the curve.
Different shaped curves of force versus time are obtained for the different bumpers. The spring and magnetic bumpers result in nearly elastic collisions while the clay produces a completely inelastic collision. The area under the clay force curve is half the area under the spring or magnetic force curves because the cart does not rebound in the clay collision.
Since the the Smart Cart is capable of measuring both force and velocity, it eliminates the need for any external sensor. No interface is required and no wires interfere with the motion because the Smart Cart transmits data wirelessly over Bluetooth® 4.0.