A place kicker must kick a 36.0 m (40 yd) to win the football game as time expir

Question

A place kicker must kick a 36.0 m (40 yd) to win the football game as time expires. The crossbar of the uprights is 3.05 m high. The ball is kicked at 21.0 m/s at an angle 54.0 degree to the horizontal. (a) By how much does the ball clear or fall short of the crossbar? If there are 4 s left on the game clock and game clock is started 1 s before the kicker kicks the ball, (b) does time for the game expire by the time the ball passes the goalposts? (c) Does time expire by the time the ball hits the ground?

Explanation / Answer

here,

x = 36 m

initial speed , u = 21 m/s

theta = 54 degree

a)

the ball height at cross bar , H = x * tan(theta) - g * x^2 /(2 * u^2 * cos^2(theta))

H = 36 * tan(54) - 9.81 * 36^2 /( 2 * 21^2 * cos^2(54)) m

H = 7.82 m

so the ball is ( 7.82 - 3.05 = 4.78 m) above the cross bar

b)

at t = 3 s

the horizontal distance , x = u * cos(theta) * t

x = 21 * cos(54) * 3 = 37.03 m

so the ball passes the goal posts before the time expires

c)

when the time expires , the ball does not hit the ground

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.