- #1

- 3

- 0

1)A place kicker must kick a football from a point 33.5 m from the goal, and the ball must clear the crossbar, which is 3.05 m high. When kicked, the ball leaves the ground with a speed of 19.5 m/s at an angle of 38.0° to the horizontal.

a)By how much does the ball clear or fall short of clearing the crossbar? (Enter a positive value for clearance and a negative value for falling short.)

Do I use the equation Ymax=Voy^2/2a ? Because the correct answer should be

*-0.19 m*

b)What is the y-component of the ball's velocity as it reaches the crossbar?

I figure I use Vf = Vi +a(2*distance)/(Vf +Vi) but I don’t know how to get distance from the first part to do this. The correct answer should be

*-9.38 m/s*

2) A ball is projected horizontally from the edge of a table that is 1.08 m high, and it strikes the floor at a point 1.24 m from the base of the table.

a)What is the initial speed of the ball?

*2.64 m/s*

b)How high is the ball above the floor when its velocity vector makes a 47.6° angle with the horizontal?

*6.53×10-1 m*

I got part a) right by using t=sqRoot(2h/g) and d/t=v but I have no idea what to do with part b!

3) One of the fastest recorded pitches in major-league baseball, thrown by Nolan Ryan in 1974, was clocked at 100.8 mi/hr. If a pitch were thrown horizontally with this velocity, how far would the ball fall vertically by the time it reached a horizontal distance of 65.0 ft? (Neglect air resistance.)

*9.49×10-1 m*

I found time using the Kinematics equations then plugged it into y=.5at^2 but that doesn’t seem to work.