A ball thrown vertically upward with a speed of 19.6 m / s from the top of a tower returns to the earth in 6 second. What is the height of the tower?

Question

A ball thrown vertically upward with a speed of 19.6 m / s from the top of a tower returns to the earth in 6 second. What is the height of the tower? (A) 40 m (B) 58.8 m (C) 50 m (D) 70 m

Tardigrade Admin · Accepted Answer

u =-19.6 ms -1 a =9.8 ms -2 t =6 s S = ut +(1/2) at 2 S =-19.6 × 6+(1/2) × 9.8 × 62 =-19.6 × 6+4.9 × 36 S =58.8 m

Q. A ball thrown vertically upward with a speed of $19.6 m / s$ from the top of a tower returns to the earth in $6$ second. What is the height of the tower?

$40 m$

$58.8 m$

$50 m$

$70 m$

$u = - 19.6 m s^{- 1} a = 9.8 m s^{- 2} t = 6 s$
$S = u t + \frac{1}{2} a t^{2}$
$S = - 19.6 \times 6 + \frac{1}{2} \times 9.8 \times 6^{2}$
$= - 19.6 \times 6 + 4.9 \times 36$
$S = 58.8 m$

Q. A ball thrown vertically upward with a speed of 19.6m/s from the top of a tower returns to the earth in 6 second. What is the height of the tower?

40m

58.8m

50m

70m