4th Quarter MIDTERM ASSESSMENT

Figure 1 below demonstrates the positions of the ball thrown upward. Which of the following is TRUE about the direction of the ball's velocity and acceleration between points A and B?

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In Newtonian mechanics, linear momentum, translational momentum, or simply momentum is the product of the mass and velocity of an object. How can you increase the linear momentum of something?

• Increase its mass and velocity.

• Decrease its mass and velocity.

• Increase its mass, decrease its velocity.

• Decrease its mass, increase its velocity.

In certain martial arts, people practice breaking a piece of wood with the side of their bare hands. Given the same change in momentum, which of the following statements below explains how this can be done without injury to the hand?

• When the time interval is bigger, the impact force is bigger.

• When the time interval is bigger, the impact force is smaller.

• When the time interval is smaller, the impact force is bigger.

• When the time interval is smaller, the impact force is smaller.

Airbags inflate upon impact and provide a barrier between the driver and the steering wheel. Which of the following explains why airbags can reduce injuries in a vehicle collision?

• They will catch your body as the vehicle moves forward, reducing your inertia.

• When a vehicle is in motion, all of its passengers are moving at the same velocity as the vehicle.

• They increase the amount of time it takes for the second collision to occur, which decreases the force and severity of injuries

• They decrease the amount of time it takes for the second collision to occur, which decreases the force and severity of injuries.

Two billiard balls approach each other at equal speeds. If they collide in a perfectly elastic collision, what would happen to their velocities after collision?

• Zero

• Same in magnitude and direction

• Same in magnitude but opposite in direction

• Different in magnitude and opposite in direction

To apply the concept of momentum, you were challenged to drop a raw egg from a 10-m high building to the ground without breaking. Which of the following is the BEST tactic for this egg-drop activity?

• . Wrap the egg with a handkerchief or with wet paper towels

• . Look for a grassy area where the egg be possible dropped without breaking.

• Before dropping, position the egg so that it lands with the strongest part of its shell

• . Construct a landing craft to cushion it against the impact of landing and to slow down its descent speed

Two skaters are in a position to push away from each other. If they are initially at rest before pushing, what can be said of their momentum?

• Zero

• Equal to the sum of their masses

• Equal to the sum of their weights

• Equal to the sum of their masses and velocities

A 0.30 kg cart moving on an air track at 1.2 m/s collides and sticks to another cart of mass 0.50 kg which was stationary before the collision. What is the velocity of the combined carts after collision?

• 0.45 m/s
• 0.35 m/s     

• 0.55 m/s

• 0.65 m/s

When energy changes from one form to another, the amount of energy stays the same. This principle is held by which of the following laws?

• . Law of Energy

• Law of Conservation of Mass

• Law of Conservation of Energy

• Law of Chemical Combination

Anything that is moving has kinetic energy. The following sources possess kinetic energy that can be converted into electrical energy EXCEPT:

• Coal
• Wind

• Tidal current

• Falling water