Question

An object is thrown upward with a speed of 15 m/s on the surface of planet X where the acceleration due to gravity is 2.5 m/s2. How long does it take for the object to return to where it is thrown?

Answer 1

Answer:

12s

Explanation:

the formula is

s = u×t + 0.5×a×t²

where:

s is the displacement of the object at this time (so it's equal to 0)

u is the initial speed

t is the time you have to find

a is the acceleration due to gravity

$0 = 15 \frac{m}{s} \times t + 0.5 \times 2.5 \frac{m}{{s}^{2} } \times {t}^{2}$

$15 \frac{m}{s} \times t = 0.5 \times 2.5 \frac{m}{ {s}^{2} } \times {t}^{2}$

$15 \frac{m}{s} = 1.25 \frac{m}{{s}^{2} } \times {t}$

$t = \frac{15 \frac{m}{ {s}^{} } }{1.25 \frac{m}{ {s}^{2} } }$

$t = 12s$