Problem 12Q

A baseball player hits a ball straight up into the air. It leaves the bat with a speed of120 km/h. In the absence of air resistance, how fast would the ball be traveling when it is caught at the same height above the ground as it left the bat? Explain.

Solution 12Q

A baseball is thrown upward with a velocity of 120km/h. We will find its speed when it comes back to level as it is hit.

It makes the solution of free fall problems easier, if we choose the initial point as origin and the initial velocity direction to be positive.

Step 1 of 2

(initial velocity of baseball)

(gravitational acceleration is negative because we chose the downward to be negative)

(the object is passing back to the point it is thrown. Where the velocity is asked. The initial and final points are the same points. So displacement is zero)

(final velocity of baseball)