Notes

ACT 1
1. I am a gymnast. I need to (bend) my knees when landing from a certain height to (increase) the time of contact with the floor thus (reducing) the force of impact.

2. Cars are designed with (airbags) because it can lessen or prevent injuries in the event of crash or collision. The inflation of the airbag is initiated by crash sensors. This (decreases) the impact force by (increasing) the time of contact.

3. Car manufacturers design (crumple zones) into cars so that car will likely be crumpled rather than rebounded in a collision. When the car crumples, the change in the car’s momentum happens over a (long) time. This (decreases) the force of impact on the passengers and thereby increasing chances of survival.

4. Baseball players need to use ( padded gloves). Its padding is slightly compressible thus (reducing) the impact force on the player’s hand by (increasing) the time of contact.

5. When catching a baseball, the catcher pulls his hand (backwards) with the moving ball. This (decreases)
the impact of catching the fast-moving ball to your hand because by doing so, time of contact was been (increased).


ACT 3

1. In a collision, an object experiences a force for a given amount of time that results in its mass undergoing a change in velocity (i.e., that results in a momentum change).

There are four physical quantities mentioned in the above statement - force, time, mass, and velocity change. The force multiplied by the time is known as the impulse and the mass multiplied by the velocity change is known as the change in momentum. The impulse experienced by an object is always equal to the change in its momentum.

2. Yes, in order for a bullet to have the same momentum as a truck, it must have a higher velocity because the two masses are not the same.

3. A seatbelt expands the stopping force required to decelerate the rider across their body. This stops the body from hitting the steering column or windshield of a high-speed car, which could easily result in injury or even death.