Answer:
5.0 m
Explanation:
The velocity of the object at time t is given by
[tex]v=at[/tex]
where a=9.8 m/s^2 is the acceleration of gravity and t is the time. If we substitute v=7 m/s, we can find the time t at which the velocity became 7 m/s:
[tex]t=\frac{v}{a}=\frac{7 m/s}{9.8 m/s^2}=0.71 s[/tex]
The height of the object at time t, h(t), is given by the equation
[tex]h(t)=h_0 -\frac{1}{2}at^2[/tex]
where [tex]h_0 = 7.5 m[/tex] is the initial height. By substituting t=0.71 s inside the equation, we find the height h(t) at which the velocity is 7 m/s:
[tex]h(0.71 s)=7.5 m- \frac{1}{2}(9.8 m/s^2)(0.71 s)^2=5.0 m[/tex]
