A stone is thrown straight downward with a speed of 20 m/s from the top of a tall building. If the stone strikes
the ground 3.0 s later, about how tall is the building? Assume air resistance is negligible.
(A) 45 m
(B) 60 m
(C) 90 m
(D) 105 m
(E) 120 m
A coyote can run at a speed of 20 m/s while a prairie dog can manage only 5.5 m/s. If a prairie dog is 45 m in
front of a coyote, what is the maximum time it has to reach its hole without being caught?
(A) 2.3 s
(B) 3.1 s
(C) 5.4 s
(D) 5.9 s
(E) 8.2 s
A model rocket accelerates from rest upwards at 50 m/s2
(A) 100 m
(B) 510 m
(C) 610 m
(D) 1020 m
(E) 1220 m
for 2.0 s before its engine burns out. The rocket then coasts upward. What is the maximum height that the rocket reaches?
You may assume air resistance is negligible.
A hunter in a forest walks 800 m west. He then turns south and walks 400 m before turning west again and walking a final 300 m. At the end of the walk, what is the magnitude of the hunter's displacement from the beginning?
(A) 640 m
(B) 890 m
(C) 1170 m
(D) 1390 m
(E) 1500 m