Hanging Mass and Car Lab

 

How do the predicted velocity and the measured velocity compare in each case? Did your measurements agree with your initial prediction? If not, why?

Our calculated values were slightly different than our experimental values with the average of 0.027 uncertainty value. The uncertainty varied through different masses. When we did our calculations, our system was ideal. We didn’t account for friction in the track, friction between the string and the pulley, air resistance and stretching of the string were unaccounted. There is also human errors such as not releasing the car in an ideal way, we might have pushed when we release it.

Does the launch velocity of the car depend on the mass? The mass of the block? The distance the black falls? Is there a choice of distance and block mass for which the mass of the car does not make much difference to its launch velocity?

Yes, the launch velocity of the car depends on the mass of the block, the distance the block falls, and the mass of the car. Heavier block and a grater fall distance would increase the velocity, but a heavier car would decrease the velocity. In some scenarios where the block weighs a lot and the distance is great, the mass of the car wouldn’t make a lot of difference in the launch velocity.

If the same mass block falls through the same distance but the car’s mass changes, does the force that string exerts on the car change? Is the force exerted by the string always equal to the weight of the hanging abject?

Yes, the force that the string exerts on the car changes when the mass of the cart changes even if the block’s mass and the distance doesn’t change. The tension is not always equal to the weight of the block since it also depends on the acceleration which is affected by the car’s mass.

Was the frictional force the same whether or not the string exerted a force on it? Does this agree with your initial prediction? In not, why?

No, the frictional force is not the same when the string exerted a force on the system which doesn’t agree with the prediction. The frictional force depends on the system’s different conditions such as masses and the falling distance. While the string pulls the car, friction is the opposite of the motion but when the mass hits the ground the friction slows down since the car keeps moving without the block’s mass’ effects. This means that the frictional force can vary at different conditions of the system.