Question

HELP

Answer 1

Here the acceleration is g=-9.81 m/s^2.
Let initial location be y=0.
Final location is y=-10.
The kinematics equation is:
initial velocity, v0=20 m/s upwards
\(y(t)=v0(t)+(1/2)gt^2=-10\)
Substitute v0=20, g=-9.81 and solve for t.
Reject negative roots.