Question

a football is kicked with a velocity of 20m/s at an angle of 45 degree ....find the time taken by the ball to hit the ground

Answer 1

This tests the time of flight of a horizontal projection.

Time of flight = 2 U sin 45° / g

U = 20 m/s

g = 10

Sin 45 = 0.7071

(2 × 20 × 0.7071) / 10 = 2.8284 Seconds

Answer 2

Answer:

${\bold{\therefore Time\:taken=2\sqrt{2}\:sec}}$

Explanation:

${\bold{\huge{\underline{SOLUTION-}}}}$

• In the given question information given about a football which is kicked with a velocity at an angle of 45°.

• We have to find time of flight or time taken the football to reach ground.

$\underline \bold{Given : } \\ \implies Initial \: velocity(u) = 20 \: m/s \\ \\ \implies Angle \: of \: projection = 45 \degree \\ \\ \implies Gravity(g )=10 \: m {s}^{2} \\ \\ \underline\bold{to \: find :} \\ \implies Time \: of \: flight = ?$

• According to given question :

$\bold{By \: formula \: time \: of \: flight : } \\ \implies t = \frac{2usin \theta}{g} \\ \\ \implies t = \frac{2 \times 20 \times sin 45\degree}{10} \\ \\ \implies t = 2 \times 2 \times \frac{1}{ \sqrt{2} } \\ \\ \bold{\implies t = 2 \sqrt{2} \: sec}$