Problems Based On Free Fall

1. A ball is thrown up in the air with an initial velocity of 40 m/s. What is the ball's velocity after 2 seconds?

0 m/s

20 m/s traveling upward

20 m/s traveling downward

40 m/s traveling downward

When a ball is thrown up in the air, its velocity decreases due to the force of gravity acting against it. After 2 seconds, the ball's velocity would have decreased to 20 m/s. The direction of the velocity is upward because the ball is still moving in the opposite direction of gravity. Therefore, the correct answer is 20 m/s traveling upward.

Explanation

When a ball is thrown up in the air, its velocity decreases due to the force of gravity acting against it. After 2 seconds, the ball's velocity would have decreased to 20 m/s. The direction of the velocity is upward because the ball is still moving in the opposite direction of gravity. Therefore, the correct answer is 20 m/s traveling upward.

2. A ball is thrown up in the air with an initial velocity of 40 m/s. What is the ball's velocity after 6 seconds?

20 m/s traveling upward.

10 m/s traveling downward.

20 m/s traveling downward.

30 m/s traveling downward.

When a ball is thrown up in the air, its velocity decreases due to the force of gravity. After 6 seconds, the ball would have reached its maximum height and started to fall back down. Since the initial velocity was upward, the ball's velocity after 6 seconds would be downward. The velocity would be 20 m/s, as the ball is now falling due to gravity.

Explanation

When a ball is thrown up in the air, its velocity decreases due to the force of gravity. After 6 seconds, the ball would have reached its maximum height and started to fall back down. Since the initial velocity was upward, the ball's velocity after 6 seconds would be downward. The velocity would be 20 m/s, as the ball is now falling due to gravity.

3. In a normal environment, why does a bowling ball and feather hit the ground at different times when dropped from the same height?

They don't; they hit the ground at the same time.

One is more dense than the other.

One is heavier than the other.

Air resistance

The reason a bowling ball and feather hit the ground at different times when dropped from the same height in a normal environment is due to air resistance. Air resistance affects objects differently based on their shape and surface area. The feather experiences more air resistance than the bowling ball due to its larger surface area and lighter weight. This causes the feather to fall slower and take more time to reach the ground compared to the bowling ball.

Explanation

The reason a bowling ball and feather hit the ground at different times when dropped from the same height in a normal environment is due to air resistance. Air resistance affects objects differently based on their shape and surface area. The feather experiences more air resistance than the bowling ball due to its larger surface area and lighter weight. This causes the feather to fall slower and take more time to reach the ground compared to the bowling ball.

4. A ball is thrown in the air with an initial velocity of 40 m/s. How long does it take to reach back to the point it was thrown from?

4 seconds

2 seconds

6 seconds

8 seconds

The ball takes 8 seconds to reach back to the point it was thrown from because the time it takes for an object to reach its initial position after being thrown vertically upwards is equal to twice the time it takes for the object to reach its highest point. In this case, the ball reaches its highest point in 4 seconds, so it will take another 4 seconds for it to reach back to its initial position, resulting in a total time of 8 seconds.

Explanation

The ball takes 8 seconds to reach back to the point it was thrown from because the time it takes for an object to reach its initial position after being thrown vertically upwards is equal to twice the time it takes for the object to reach its highest point. In this case, the ball reaches its highest point in 4 seconds, so it will take another 4 seconds for it to reach back to its initial position, resulting in a total time of 8 seconds.

5. What happens to the total distance that a ball travels as it falls off the side of a cliff?

The distance remains constant

The distance increases at a uniform rate

The distance increases at a nonuniform rate

The distance decreases at a uniform rate

As the ball falls off the side of a cliff, the distance it travels increases at a nonuniform rate. This means that the ball covers more distance in each subsequent unit of time. This is because the ball accelerates due to the force of gravity acting on it. Initially, the ball falls slowly, but as it gains speed, it covers larger distances in the same amount of time. Therefore, the total distance traveled by the ball increases at a nonuniform rate.

Explanation

As the ball falls off the side of a cliff, the distance it travels increases at a nonuniform rate. This means that the ball covers more distance in each subsequent unit of time. This is because the ball accelerates due to the force of gravity acting on it. Initially, the ball falls slowly, but as it gains speed, it covers larger distances in the same amount of time. Therefore, the total distance traveled by the ball increases at a nonuniform rate.