A placekicker must kick a football from a point 36.0 m (about 40 yards) from the goal. Half the crowd hopes the ball will clear the crossbar, which is 3.05 m high. When kicked, the ball leaves the ground with a speed of 21.6 m/s at an angle of 45.0° to the horizontal.
(a) By how much does the ball clear or fall short of clearing the crossbar? (Enter a negative answer if it falls short.)

Question

A placekicker must kick a football from a point 36.0 m (about 40 yards) from the goal. Half the crowd hopes the ball will clear the crossbar, which is 3.05 m high. When kicked, the ball leaves the ground with a speed of 21.6 m/s at an angle of 45.0° to the horizontal.
(a) By how much does the ball clear or fall short of clearing the crossbar? (Enter a negative answer if it falls short.)

mani_jha · Answer

The height attained by the ball will be:
$$v ^{2}\sin ^{2}\theta/2g$$
v=21.6 theta =45 g=9.8

mani_jha · Answer

The height comes out to be 11.89 m

anonymous · Answer

for x = 36 m
x = v cos(45)  t
36= 21.6/sqrt 2 t
find t and then substitute in the equation
y = v sin45 t - 1/2 gt^2
based on the y u get u could the answer the question