Thursday, 15 November 2007 - 5:30 PM EST

1. An air bag reduces the risk of injury because it "gives" when it is struck by an object, such as a human head. The air bag allows for your head to change its speed over a longer period of time so that your head does not stop moving in a split second, which is when injuries occur.

 2. I think that the rubber ball will cause the door to close because all of the momentum is conserved, no momentum is lost.

Thursday, 15 November 2007 - 5:34 PM EST

what are the questions i dont have my lab packet

Thursday, 15 November 2007 - 5:54 PM EST

2. The clay will close the door better than the rubber ball because it applies more force. The ball does not stop when it hits the door therefore it has less force when it hits the door, but the clay stops when it hits the door.

Thursday, 15 November 2007 - 6:33 PM EST

I can't answer this blog because I do not have the lab packet with me.

Thursday, 15 November 2007 - 6:54 PM EST

I believe that the clay will close the door because there will be a greater change in momentum because the same amount of force is applied for a greater amount of time. The rubber ball will hit the door for a fraction of a second while the clay sticks to the door and applies the same force for a greater period of time, resulting in a greater impulse, meaning more momentum, implying that the door will have a higher velocity because the mass is the same, meaning the door is more likely to close.

Thursday, 15 November 2007 - 6:58 PM EST

To Derek and anyone else without a packet, the question is: "You want to close an open door by throwing either a 400-g lump of clay or a 400-g rubber ball toward it. You can throw either object with the same speed, but they are different in that the rubber ball bounces off the door while the clay just sticks to the door. Which projectile will apply the larger impulse to the door and be more likely to close it?"

Thursday, 15 November 2007 - 7:05 PM EST

I think the clay will close the door better than the ball would. This is because if they are both thrown with the same force you would want to go with the one that would affect the door for the longer amount of time thus causing a greater change in momentum. The clay sticks to the door giving it more time but the ball would bounce off, giving it less time to impact the door.

Thursday, 15 November 2007 - 7:15 PM EST

I think that the clay will close the door with a greater impulse.  Since the ball bounces off the door when it is thrown, the door only experiences contact with the ball for a brief amount of time.  The clay will stick to the door, allowing for it to make contact with the door for a longer period of time.  Since they are thrown with the same force, the greater the time, the greater the impulse will be.  The clay has a greater chance to close the door.

Thursday, 15 November 2007 - 7:48 PM EST

I think that the clay would be more effective in trying to close the door. All of the momentum would be transfered to the door, since the clay will stick. It seems like that will do more than throwing a ball at the door, which will take momentum away when it bounces off the door.

Thursday, 15 November 2007 - 8:14 PM EST

I think that the clay will shut the door better. Since the ball just bounces off, all of the force isn't going directly to the door unlike when the clay hits the door and its force is applied longer and therefore it is able to close the door better.

Thursday, 15 November 2007 - 8:48 PM EST

The clay would have a larger impulse and be better for closing the door. The rubber ball would put force on the door for a very short amount of time because it would quickly bounce off. The clay would stick to the door increasing the time the force is applied which would increase the impulse.

Thursday, 15 November 2007 - 9:30 PM EST

I believe that the clay will close the door rather than rubber ball because the amount of time the ball is in contact with the door. The longer it is in contact with the door, the greater momentum. Because the rubber ball is an elastic collision, the kinetic energy stays mostly within the ball as it bounces back, applying only a small velocity to the door. However, when the clay sticks to the door as as inelastic collision, the energy is transfered into the movement of the door.

Thursday, 15 November 2007 - 9:34 PM EST

I think the clay would make the door close better than if you threw a rubber ball. I think this b/c the clay will stick to the door making more force act on the door and making the door close more. The rubber ball would bounce off the door and wouldn't apply as much force to the door. The clay would be in contact with the door for a longer time than the rubber ball which would be in contact with the door for only a split second before bouncing off. The longer time the clay and door are in contact will make the clay close the door more then the rubber ball.

Thursday, 15 November 2007 - 9:49 PM EST

The clay would probably more affective while closing the door rather than the ball. This is because the clay would have more time forcing itself against the door while the ball would simply just bounce right back off. Factoring all of this the momentum would be much greater with the clay.

Thursday, 15 November 2007 - 10:05 PM EST

I think the clay ball will apply the larger impulse to the door because it will apply a stronger force to the door because it will stick to the door unlike the rubberball, which will only hit it at a split second. The clay ball will cause the door to have a greater change of momentum, thus giving it a greater impulse.

Thursday, 15 November 2007 - 11:03 PM EST

I think that the clay would be best to close the door.  The reason for this is that the clay will stick to the door, transfering all its energy and force onto the door causing it to close.  I think that the rubber ball will bounce right off the door, not transfering as much force or energy as the clay ball would.