Question

5. You are on a 5 m high rook and throw a ball upwards at 10 m/s. It lands on the ground below the roof.

a. How long was the rock in the air?
b. What was the final velocity?

Answer 1

The rock was in the air for approximately 2.04 seconds and its final velocity was approximately -19.99 m/s.

Step-by-step explanation:

To calculate how long the rock was in the air, we can use the equation:

time = 2 * initial velocity / acceleration

Since the rock was thrown upwards, the acceleration is -9.8 m/s^2 (negative due to gravity). The initial velocity is 10 m/s. Plugging in these values, we get:

time = 2 * 10 m/s / 9.8 m/s^2 = 2.04 seconds

Therefore, the rock was in the air for approximately 2.04 seconds.

To find the final velocity, we can use the equation:

final velocity = initial velocity + acceleration * time

Since the rock was thrown upwards, the acceleration is -9.8 m/s^2. Plugging in the values of initial velocity (10 m/s) and time (2.04 seconds), we get:

final velocity = 10 m/s + (-9.8 m/s^2) * 2.04 s = -19.99 m/s

The negative sign indicates that the final velocity is directed downwards. Therefore, the final velocity of the rock is approximately -19.99 m/s.