Final answer:
The rock takes 3.47 seconds to strike the ground and has a velocity of 52.8 m/s just before it strikes the ground.
Step-by-step explanation:
To calculate the time it takes for a rock to strike the ground when thrown vertically upward, we can use the equation:
t = 2v/g
where t is the time, v is the initial velocity, and g is the acceleration due to gravity (which is approximately 9.8 m/s^2). In this problem, v = 17.0 m/s. Substituting these values into the equation, we get:
t = 2(17.0)/9.8 = 3.47 seconds
To calculate the speed of the rock just before it strikes the ground, we can use the equation:
v = u + gt
where v is the final velocity, u is the initial velocity, g is the acceleration due to gravity, and t is the time. In this case, u = 17.0 m/s and g = 9.8 m/s^2. Substituting these values into the equation, we get:
v = 17.0 + (9.8)(3.47) = 52.8 m/s