Question

Suppose that a stone is thrown straight downward from a high cliff. If its speed at the time it is released is 2 m/s, what is its speed after 4 seconds?

A. 2 m/s
B. More than 2 m/s
C. Less than 2 m/s
D. The exact speed cannot be determined from the given information.

Answer 1

The speed of the stone after 4 seconds is -37.2 m/s, moving downwards.

Step-by-step explanation:

When a stone is thrown straight downward from a high cliff, it experiences a downward acceleration due to gravity. This means that its speed will increase as it falls. The speed after 4 seconds can be calculated using the equation:

final speed = initial speed + (acceleration * time)

Since the stone is thrown downwards, the initial speed is already in the downward direction and positive. The acceleration due to gravity is always downward and negative. Plugging in the values:

final speed = 2 m/s + (-9.8 m/s^2) * 4 s

final speed = 2 m/s - 39.2 m/s

final speed = -37.2 m/s

So the speed after 4 seconds is -37.2 m/s, which means it is moving downwards at a speed of 37.2 m/s.