Question

Show that there are two values of
time for which a projectile is at the same height. Also
show that the sum of these two times is equal to the time
of flight.​

Answer 1

Explanation:

ANSWER

From figure, u

y

=u sinθ a

y

=−g

y-direction : S

y

=u

y

t+

2

1

a

y

t

2

∴ h=(usinθ)t−

2

gt

2

⟹ t

2

−(

g

2u

sinθ)t+

g

2h

=0 ...............(1)

Equation (1) has two roots t

1

and t

2

, thus there are two values of time for which a projectile is at the same height.

Sum of roots of (1) t

1

+t

2

=

a

−b

=

g

2usinθ

=T (Time of flight)

solution